diff --git a/compiler/base/contact.py b/compiler/base/contact.py
index c3fa810d..5c300033 100644
--- a/compiler/base/contact.py
+++ b/compiler/base/contact.py
@@ -1,11 +1,11 @@
-import design
+import hierarchy_design
 import debug
 import utils
 from tech import drc
 from vector import vector
 
 
-class contact(design.design):
+class contact(hierarchy_design.hierarchy_design):
     """
     Object for a contact shape with its conductor enclosures.
     Creates a contact array minimum active or poly enclosure and metal1 enclosure.
@@ -31,7 +31,7 @@ class contact(design.design):
                                                        dimensions[0],
                                                        dimensions[1])
                                        
-        design.design.__init__(self, name)
+        hierarchy_design.hierarchy_design.__init__(self, name)
         debug.info(4, "create contact object {0}".format(name))
 
         self.layer_stack = layer_stack
@@ -158,6 +158,9 @@ class contact(design.design):
                       width=well_width,
                       height=well_height)
         
+    def analytical_power(self, proc, vdd, temp, load):
+        """ Get total power of a module  """
+        return self.return_power()
 
 
 # This is not instantiated and used for calculations only.
@@ -167,4 +170,5 @@ active = contact(layer_stack=("active", "contact", "poly"))
 poly = contact(layer_stack=("poly", "contact", "metal1"))
 m1m2 = contact(layer_stack=("metal1", "via1", "metal2"))
 m2m3 = contact(layer_stack=("metal2", "via2", "metal3"))
+#m3m4 = contact(layer_stack=("metal3", "via3", "metal4"))
 
diff --git a/compiler/base/design.py b/compiler/base/design.py
index 794bb79a..09522f35 100644
--- a/compiler/base/design.py
+++ b/compiler/base/design.py
@@ -1,5 +1,5 @@
-import hierarchy_layout
-import hierarchy_spice
+from hierarchy_design import hierarchy_design
+import contact
 import globals
 import verify
 import debug
@@ -7,46 +7,24 @@ import os
 from globals import OPTS
 
 
-class design(hierarchy_spice.spice, hierarchy_layout.layout):
+class design(hierarchy_design):
     """
-    Design Class for all modules to inherit the base features.
-    Class consisting of a set of modules and instances of these modules
+    This is the same as the hierarchy_design class except it contains
+    some DRC constants and analytical models for other modules to reuse.
+
     """
-    name_map = []
-    
 
     def __init__(self, name):
-        self.gds_file = OPTS.openram_tech + "gds_lib/" + name + ".gds"
-        self.sp_file = OPTS.openram_tech + "sp_lib/" + name + ".sp"
-
-        self.name = name
-        hierarchy_layout.layout.__init__(self, name)
-        hierarchy_spice.spice.__init__(self, name)
-
+        hierarchy_design.__init__(self,name)
+        
         self.setup_drc_constants()
-        
-        # Check if the name already exists, if so, give an error
-        # because each reference must be a unique name.
-        # These modules ensure unique names or have no changes if they
-        # aren't unique
-        ok_list = ['ms_flop',
-                   'dff',
-                   'dff_buf',
-                   'bitcell',
-                   'contact',
-                   'ptx',
-                   'sram',
-                   'hierarchical_predecode2x4',
-                   'hierarchical_predecode3x8']
-        if name not in design.name_map:
-            design.name_map.append(name)
-        else:
-            for ok_names in ok_list:
-                if ok_names in self.__class__.__name__:
-                    break
-            else:
-                debug.error("Duplicate layout reference name {0} of class {1}. GDS2 requires names be unique.".format(name,self.__class__),-1)
-        
+
+        self.m1_pitch = max(contact.m1m2.width,contact.m1m2.height) + max(self.m1_space, self.m2_space)
+        self.m2_pitch = max(contact.m2m3.width,contact.m2m3.height) + max(self.m2_space, self.m3_space)
+        # SCMOS doesn't have m4...
+        #self.m3_pitch = max(contact.m3m4.width,contact.m3m4.height) + max(self.m3_space, self.m4_space)
+        self.m3_pitch = self.m2_pitch
+
     def setup_drc_constants(self):
         """ These are some DRC constants used in many places in the compiler."""
         from tech import drc
@@ -61,70 +39,14 @@ class design(hierarchy_spice.spice, hierarchy_layout.layout):
         self.m3_space = drc["metal3_to_metal3"]
         self.active_width = drc["minwidth_active"]
         self.contact_width = drc["minwidth_contact"]
-        
+
         self.poly_to_active = drc["poly_to_active"]
         self.poly_extend_active = drc["poly_extend_active"]
         self.contact_to_gate = drc["contact_to_gate"]
         self.well_enclose_active = drc["well_enclosure_active"]
         self.implant_enclose_active = drc["implant_enclosure_active"]
         self.implant_space = drc["implant_to_implant"]   
-        
-    def get_layout_pins(self,inst):
-        """ Return a map of pin locations of the instance offset """
-        # find the instance
-        for i in self.insts:
-            if i.name == inst.name:
-                break
-        else:
-            debug.error("Couldn't find instance {0}".format(inst_name),-1)
-        inst_map = inst.mod.pin_map
-        return inst_map
-        
 
-    def DRC_LVS(self, final_verification=False):
-        """Checks both DRC and LVS for a module"""
-        if OPTS.check_lvsdrc:
-            tempspice = OPTS.openram_temp + "/temp.sp"
-            tempgds = OPTS.openram_temp + "/temp.gds"
-            self.sp_write(tempspice)
-            self.gds_write(tempgds)
-            debug.check(verify.run_drc(self.name, tempgds) == 0,"DRC failed for {0}".format(self.name))
-            debug.check(verify.run_lvs(self.name, tempgds, tempspice, final_verification) == 0,"LVS failed for {0}".format(self.name))
-            os.remove(tempspice)
-            os.remove(tempgds)
-
-    def DRC(self):
-        """Checks DRC for a module"""
-        if OPTS.check_lvsdrc:
-            tempgds = OPTS.openram_temp + "/temp.gds"
-            self.gds_write(tempgds)
-            debug.check(verify.run_drc(self.name, tempgds) == 0,"DRC failed for {0}".format(self.name))
-            os.remove(tempgds)
-
-    def LVS(self, final_verification=False):
-        """Checks LVS for a module"""
-        if OPTS.check_lvsdrc:
-            tempspice = OPTS.openram_temp + "/temp.sp"
-            tempgds = OPTS.openram_temp + "/temp.gds"
-            self.sp_write(tempspice)
-            self.gds_write(tempgds)
-            debug.check(verify.run_lvs(self.name, tempgds, tempspice, final_verification) == 0,"LVS failed for {0}".format(self.name))
-            os.remove(tempspice)
-            os.remove(tempgds)
-
-    def __str__(self):
-        """ override print function output """
-        return "design: " + self.name
-
-    def __repr__(self):
-        """ override print function output """
-        text="( design: " + self.name + " pins=" + str(self.pins) + " " + str(self.width) + "x" + str(self.height) + " )\n"
-        for i in self.objs:
-            text+=str(i)+",\n"
-        for i in self.insts:
-            text+=str(i)+",\n"
-        return text
-     
     def analytical_power(self, proc, vdd, temp, load):
         """ Get total power of a module  """
         total_module_power = self.return_power()
diff --git a/compiler/base/hierarchy_design.py b/compiler/base/hierarchy_design.py
new file mode 100644
index 00000000..87659bd7
--- /dev/null
+++ b/compiler/base/hierarchy_design.py
@@ -0,0 +1,111 @@
+import hierarchy_layout
+import hierarchy_spice
+import globals
+import verify
+import debug
+import os
+from globals import OPTS
+
+
+class hierarchy_design(hierarchy_spice.spice, hierarchy_layout.layout):
+    """
+    Design Class for all modules to inherit the base features.
+    Class consisting of a set of modules and instances of these modules
+    """
+    name_map = []
+    
+
+    def __init__(self, name):
+        self.gds_file = OPTS.openram_tech + "gds_lib/" + name + ".gds"
+        self.sp_file = OPTS.openram_tech + "sp_lib/" + name + ".sp"
+
+        self.name = name
+        hierarchy_layout.layout.__init__(self, name)
+        hierarchy_spice.spice.__init__(self, name)
+
+        
+        # Check if the name already exists, if so, give an error
+        # because each reference must be a unique name.
+        # These modules ensure unique names or have no changes if they
+        # aren't unique
+        ok_list = ['ms_flop',
+                   'dff',
+                   'dff_buf',
+                   'bitcell',
+                   'contact',
+                   'ptx',
+                   'sram',
+                   'hierarchical_predecode2x4',
+                   'hierarchical_predecode3x8']
+        if name not in hierarchy_design.name_map:
+            hierarchy_design.name_map.append(name)
+        else:
+            for ok_names in ok_list:
+                if ok_names in self.__class__.__name__:
+                    break
+            else:
+                debug.error("Duplicate layout reference name {0} of class {1}. GDS2 requires names be unique.".format(name,self.__class__),-1)
+        
+        
+    def get_layout_pins(self,inst):
+        """ Return a map of pin locations of the instance offset """
+        # find the instance
+        for i in self.insts:
+            if i.name == inst.name:
+                break
+        else:
+            debug.error("Couldn't find instance {0}".format(inst_name),-1)
+        inst_map = inst.mod.pin_map
+        return inst_map
+        
+
+    def DRC_LVS(self, final_verification=False):
+        """Checks both DRC and LVS for a module"""
+        # Unit tests will check themselves.
+        # Do not run if disabled in options.
+        if not OPTS.is_unit_test and OPTS.check_lvsdrc:
+            tempspice = OPTS.openram_temp + "/temp.sp"
+            tempgds = OPTS.openram_temp + "/temp.gds"
+            self.sp_write(tempspice)
+            self.gds_write(tempgds)
+            debug.check(verify.run_drc(self.name, tempgds) == 0,"DRC failed for {0}".format(self.name))
+            debug.check(verify.run_lvs(self.name, tempgds, tempspice, final_verification) == 0,"LVS failed for {0}".format(self.name))
+            os.remove(tempspice)
+            os.remove(tempgds)
+
+    def DRC(self):
+        """Checks DRC for a module"""
+        # Unit tests will check themselves.
+        # Do not run if disabled in options.
+        if not OPTS.is_unit_test and OPTS.check_lvsdrc:
+            tempgds = OPTS.openram_temp + "/temp.gds"
+            self.gds_write(tempgds)
+            debug.check(verify.run_drc(self.name, tempgds) == 0,"DRC failed for {0}".format(self.name))
+            os.remove(tempgds)
+
+    def LVS(self, final_verification=False):
+        """Checks LVS for a module"""
+        # Unit tests will check themselves.
+        # Do not run if disabled in options.
+        if not OPTS.is_unit_test and OPTS.check_lvsdrc:
+            tempspice = OPTS.openram_temp + "/temp.sp"
+            tempgds = OPTS.openram_temp + "/temp.gds"
+            self.sp_write(tempspice)
+            self.gds_write(tempgds)
+            debug.check(verify.run_lvs(self.name, tempgds, tempspice, final_verification) == 0,"LVS failed for {0}".format(self.name))
+            os.remove(tempspice)
+            os.remove(tempgds)
+
+    def __str__(self):
+        """ override print function output """
+        return "design: " + self.name
+
+    def __repr__(self):
+        """ override print function output """
+        text="( design: " + self.name + " pins=" + str(self.pins) + " " + str(self.width) + "x" + str(self.height) + " )\n"
+        for i in self.objs:
+            text+=str(i)+",\n"
+        for i in self.insts:
+            text+=str(i)+",\n"
+        return text
+     
diff --git a/compiler/base/hierarchy_layout.py b/compiler/base/hierarchy_layout.py
index 010680d6..58a3d1fe 100644
--- a/compiler/base/hierarchy_layout.py
+++ b/compiler/base/hierarchy_layout.py
@@ -524,6 +524,62 @@ class layout(lef.lef):
 
         return blockages
 
+    def create_horizontal_pin_bus(self, layer, pitch, offset, names, length):
+        """ Create a horizontal bus of pins. """
+        self.create_bus(layer,pitch,offset,names,length,vertical=False,make_pins=True)
+
+    def create_vertical_pin_bus(self, layer, pitch, offset, names, length):
+        """ Create a horizontal bus of pins. """
+        self.create_bus(layer,pitch,offset,names,length,vertical=True,make_pins=True)
+
+    def create_vertical_bus(self, layer, pitch, offset, names, length):
+        """ Create a horizontal bus. """
+        self.create_bus(layer,pitch,offset,names,length,vertical=True,make_pins=False)
+
+    def create_horiontal_bus(self, layer, pitch, offset, names, length):
+        """ Create a horizontal bus. """
+        self.create_bus(layer,pitch,offset,names,length,vertical=False,make_pins=False)
+
+
+    def create_bus(self, layer, pitch, offset, names, length, vertical, make_pins):
+        """ 
+        Create a horizontal or vertical bus. It can be either just rectangles, or actual
+        layout pins. It returns an map of line center line positions indexed by name.  
+        """
+
+        # half minwidth so we can return the center line offsets
+        half_minwidth = 0.5*drc["minwidth_{}".format(layer)]
+        
+        line_positions = {}
+        if vertical:
+            for i in range(len(names)):
+                line_offset = offset + vector(i*pitch,0)
+                if make_pins:
+                    self.add_layout_pin(text=names[i],
+                                        layer=layer,
+                                        offset=line_offset,
+                                        height=length)
+                else:
+                    self.add_rect(layer=layer,
+                                  offset=line_offset,
+                                  height=length)
+                line_positions[names[i]]=line_offset+vector(half_minwidth,0)
+        else:
+            for i in range(len(names)):
+                line_offset = offset + vector(0,i*pitch + half_minwidth)
+                if make_pins:
+                    self.add_layout_pin(text=names[i],
+                                        layer=layer,
+                                        offset=line_offset,
+                                        width=length)
+                else:
+                    self.add_rect(layer=layer,
+                                  offset=line_offset,
+                                  width=length)
+                line_positions[names[i]]=line_offset+vector(0,half_minwidth)
+
+        return line_positions
+    
     def add_enclosure(self, insts, layer="nwell"):
         """ Add a layer that surrounds the given instances. Useful
         for creating wells, for example. Doesn't check for minimum widths or
diff --git a/compiler/characterizer/__init__.py b/compiler/characterizer/__init__.py
index 6930a112..dc9398d0 100644
--- a/compiler/characterizer/__init__.py
+++ b/compiler/characterizer/__init__.py
@@ -1,16 +1,18 @@
 import os
 import debug
+import globals
 from globals import OPTS,find_exe,get_tool
 from .lib import *
 from .delay import *
 from .setup_hold import *
 
 
-debug.info(2,"Initializing characterizer...")
-
+debug.info(1,"Initializing characterizer...")
 OPTS.spice_exe = ""
 
 if not OPTS.analytical_delay:
+    debug.info(1, "Finding spice simulator.")
+
     if OPTS.spice_name != "":
         OPTS.spice_exe=find_exe(OPTS.spice_name)
         if OPTS.spice_exe=="":
@@ -24,6 +26,7 @@ if not OPTS.analytical_delay:
     
     if OPTS.spice_exe == "":
         debug.error("No recognizable spice version found. Unable to perform characterization.",1)
-
+else:
+    debug.info(1,"Analytical model enabled.")
 
 
diff --git a/compiler/debug.py b/compiler/debug.py
index 7001373e..1bf46db0 100644
--- a/compiler/debug.py
+++ b/compiler/debug.py
@@ -13,19 +13,19 @@ def check(check,str):
     (frame, filename, line_number, function_name, lines,
      index) = inspect.getouterframes(inspect.currentframe())[1]
     if not check:
-        print("ERROR: file {0}: line {1}: {2}".format(os.path.basename(filename),line_number,str))
+        sys.stderr.write("ERROR: file {0}: line {1}: {2}\n".format(os.path.basename(filename),line_number,str))
         assert 0
 
 def error(str,return_value=0):
     (frame, filename, line_number, function_name, lines,
      index) = inspect.getouterframes(inspect.currentframe())[1]
-    print("ERROR: file {0}: line {1}: {2}".format(os.path.basename(filename),line_number,str))
+    sys.stderr.write("ERROR: file {0}: line {1}: {2}\n".format(os.path.basename(filename),line_number,str))
     assert return_value==0
 
 def warning(str):
     (frame, filename, line_number, function_name, lines,
      index) = inspect.getouterframes(inspect.currentframe())[1]
-    print("WARNING: file {0}: line {1}: {2}".format(os.path.basename(filename),line_number,str))
+    sys.stderr.write("WARNING: file {0}: line {1}: {2}\n".format(os.path.basename(filename),line_number,str))
 
 
 def info(lev, str):
diff --git a/compiler/globals.py b/compiler/globals.py
index 86d091b1..34cfbe08 100644
--- a/compiler/globals.py
+++ b/compiler/globals.py
@@ -9,12 +9,14 @@ import optparse
 import options
 import sys
 import re
+import copy
 import importlib
 
 USAGE = "Usage: openram.py [options] <config file>\nUse -h for help.\n"
 
 # Anonymous object that will be the options
 OPTS = options.options()
+CHECKPOINT_OPTS=None
 
 def parse_args():
     """ Parse the optional arguments for OpenRAM """
@@ -102,6 +104,8 @@ def check_versions():
 
 def init_openram(config_file, is_unit_test=True):
     """Initialize the technology, paths, simulators, etc."""
+
+    
     check_versions()
 
     debug.info(1,"Initializing OpenRAM...")
@@ -112,6 +116,30 @@ def init_openram(config_file, is_unit_test=True):
 
     import_tech()
 
+    # Reset the static duplicate name checker for unit tests.
+    import hierarchy_design
+    hierarchy_design.hierarchy_design.name_map=[]
+    
+    global OPTS
+    global CHECKPOINT_OPTS
+
+    # This is a hack. If we are running a unit test and have checkpointed
+    # the options, load them rather than reading the config file.
+    # This way, the configuration is reloaded at the start of every unit test.
+    # If a unit test fails, we don't have to worry about restoring the old config values
+    # that may have been tested.
+    if is_unit_test and CHECKPOINT_OPTS:
+        OPTS.__dict__ = CHECKPOINT_OPTS.__dict__.copy() 
+        return
+    
+    # Import these to find the executables for checkpointing
+    import characterizer
+    import verify
+    # Make a checkpoint of the options so we can restore
+    # after each unit test
+    if not CHECKPOINT_OPTS:
+        CHECKPOINT_OPTS = copy.copy(OPTS)
+    
 
 
 def get_tool(tool_type, preferences):
@@ -132,15 +160,15 @@ def get_tool(tool_type, preferences):
         return(None,"")
 
     
-
 def read_config(config_file, is_unit_test=True):
     """ 
     Read the configuration file that defines a few parameters. The
     config file is just a Python file that defines some config
-    options. 
+    options. This will only actually get read the first time. Subsequent
+    reads will just restore the previous copy (ask mrg)
     """
     global OPTS
-    
+        
     # Create a full path relative to current dir unless it is already an abs path
     if not os.path.isabs(config_file):
         config_file = os.getcwd() + "/" +  config_file
@@ -164,6 +192,7 @@ def read_config(config_file, is_unit_test=True):
         # The command line will over-ride the config file
         # except in the case of the tech name! This is because the tech name
         # is sometimes used to specify the config file itself (e.g. unit tests)
+        # Note that if we re-read a config file, nothing will get read again!
         if not k in OPTS.__dict__ or k=="tech_name":
             OPTS.__dict__[k]=v
     
@@ -192,12 +221,16 @@ def read_config(config_file, is_unit_test=True):
             os.chmod(OPTS.output_path, 0o750)
     except:
         debug.error("Unable to make output directory.",-1)
-    
-        
+
         
 def end_openram():
     """ Clean up openram for a proper exit """
     cleanup_paths()
+
+    import verify
+    verify.print_drc_stats()
+    verify.print_lvs_stats()
+    verify.print_pex_stats()        
     
 
     
@@ -206,6 +239,7 @@ def cleanup_paths():
     """
     We should clean up the temp directory after execution.
     """
+    global OPTS
     if not OPTS.purge_temp:
         debug.info(0,"Preserving temp directory: {}".format(OPTS.openram_temp))
         return
@@ -275,9 +309,6 @@ def import_tech():
 
     debug.info(2,"Importing technology: " + OPTS.tech_name)
 
-    # Set the tech to the config file we read in instead of the command line value.
-    OPTS.tech_name = OPTS.tech_name
-        
     # environment variable should point to the technology dir
     try:
         OPENRAM_TECH = os.path.abspath(os.environ.get("OPENRAM_TECH"))
@@ -323,6 +354,8 @@ def print_time(name, now_time, last_time=None):
 
 def report_status():
     """ Check for valid arguments and report the info about the SRAM being generated """
+    global OPTS
+    
     # Check if all arguments are integers for bits, size, banks
     if type(OPTS.word_size)!=int:
         debug.error("{0} is not an integer in config file.".format(OPTS.word_size))
diff --git a/compiler/modules/bank.py b/compiler/modules/bank.py
index 3ed6c222..db58441a 100644
--- a/compiler/modules/bank.py
+++ b/compiler/modules/bank.py
@@ -161,10 +161,6 @@ class bank(design.design):
         else:
             self.num_col_addr_lines = 0            
 
-        # M1/M2 routing pitch is based on contacted pitch
-        self.m1_pitch = contact.m1m2.height + max(self.m1_space,self.m2_space)
-        self.m2_pitch = contact.m2m3.height + max(self.m2_space,self.m3_space)
-
         # The width of this bus is needed to place other modules (e.g. decoder)
         # A width on each side too
         self.central_bus_width = self.m2_pitch * self.num_control_lines + 2*self.m2_width
diff --git a/compiler/modules/bank_select.py b/compiler/modules/bank_select.py
index d0b3070a..2abfb3c6 100644
--- a/compiler/modules/bank_select.py
+++ b/compiler/modules/bank_select.py
@@ -56,10 +56,6 @@ class bank_select(design.design):
 
     def calculate_module_offsets(self):
         
-        # M1/M2 routing pitch is based on contacted pitch
-        self.m1_pitch = contact.m1m2.height + max(self.m1_space,self.m2_space)
-        self.m2_pitch = contact.m2m3.height + max(self.m2_space,self.m3_space)
-
         self.xoffset_nand =  self.inv4x.width + 2*self.m2_pitch + drc["pwell_to_nwell"]
         self.xoffset_nor =  self.inv4x.width + 2*self.m2_pitch + drc["pwell_to_nwell"]
         self.xoffset_inv = max(self.xoffset_nand + self.nand2.width, self.xoffset_nor + self.nor2.width) 
diff --git a/compiler/modules/control_logic.py b/compiler/modules/control_logic.py
index 33501158..8526cb43 100644
--- a/compiler/modules/control_logic.py
+++ b/compiler/modules/control_logic.py
@@ -86,10 +86,6 @@ class control_logic(design.design):
         # These aren't for instantiating, but we use them to get the dimensions
         #self.poly_contact_offset = vector(0.5*contact.poly.width,0.5*contact.poly.height)
 
-        # M1/M2 routing pitch is based on contacted pitch
-        self.m1_pitch = max(contact.m1m2.width,contact.m1m2.height) + max(drc["metal1_to_metal1"],drc["metal2_to_metal2"])
-        self.m2_pitch = max(contact.m2m3.width,contact.m2m3.height) + max(drc["metal2_to_metal2"],drc["metal3_to_metal3"])
-
         # Have the cell gap leave enough room to route an M2 wire.
         # Some cells may have pwell/nwell spacing problems too when the wells are different heights.
         #self.cell_gap = max(self.m2_pitch,drc["pwell_to_nwell"])
diff --git a/compiler/modules/hierarchical_decoder.py b/compiler/modules/hierarchical_decoder.py
index 179cc936..5742cc6c 100644
--- a/compiler/modules/hierarchical_decoder.py
+++ b/compiler/modules/hierarchical_decoder.py
@@ -45,7 +45,8 @@ class hierarchical_decoder(design.design):
         self.add_pins()
         self.create_pre_decoder()
         self.create_row_decoder()
-        self.create_vertical_rail()
+        self.create_input_rail()
+        self.create_predecode_rail()
         self.route_vdd_gnd()
 
     def add_modules(self):
@@ -60,7 +61,6 @@ class hierarchical_decoder(design.design):
 
     def add_decoders(self):
         """ Create the decoders based on the number of pre-decodes """
-        # FIXME: Only add these if needed?
         self.pre2_4 = pre2x4()
         self.add_mod(self.pre2_4)
         
@@ -68,8 +68,8 @@ class hierarchical_decoder(design.design):
         self.add_mod(self.pre3_8)
 
     def determine_predecodes(self,num_inputs):
-        """Determines the number of 2:4 pre-decoder and 3:8 pre-decoder
-        needed based on the number of inputs"""
+        """ Determines the number of 2:4 pre-decoder and 3:8 pre-decoder
+        needed based on the number of inputs """
         if (num_inputs == 2):
             return (1,0)
         elif (num_inputs == 3):
@@ -90,12 +90,6 @@ class hierarchical_decoder(design.design):
             debug.error("Invalid number of inputs for hierarchical decoder",-1)
 
     def setup_layout_constants(self):
-        # Vertical metal rail gap definition
-        self.metal2_extend_contact = (contact.m1m2.second_layer_height - contact.m1m2.contact_width) / 2
-        self.metal2_spacing = self.metal2_extend_contact  + self.m2_space
-        self.metal2_pitch = self.metal2_spacing + self.m2_width
-        self.via_shift = (contact.m1m2.second_layer_width - contact.m1m2.first_layer_width) / 2
-
         self.predec_groups = []  # This array is a 2D array.
 
         # Distributing vertical rails to different groups. One group belongs to one pre-decoder.
@@ -120,7 +114,75 @@ class hierarchical_decoder(design.design):
 
         self.calculate_dimensions()
 
+    def create_input_rail(self):
+        """ Create input rails for the predecoders """
+        # inputs should be as high as the decoders
+        input_height = self.no_of_pre2x4*self.pre2_4.height + self.no_of_pre3x8*self.pre3_8.height
+
+        # Find the left-most predecoder
+        min_x = 0
+        if self.no_of_pre2x4 > 0:
+            min_x = min(min_x, -self.pre2_4.width)
+        if self.no_of_pre3x8 > 0:
+            min_x = min(min_x, -self.pre3_8.width)
+        input_offset=vector(min_x - self.input_routing_width,0)
+
+        input_bus_names = ["A[{0}]".format(i) for i in range(self.num_inputs)]
+        self.create_vertical_pin_bus(layer="metal2",
+                                     pitch=self.m2_pitch,
+                                     offset=input_offset,
+                                     names=input_bus_names,
+                                     length=input_height)
         
+        self.connect_input_to_predecodes()
+
+
+    def connect_input_to_predecodes(self):
+        """ Connect the vertical input rail to the predecoders """
+        for pre_num in range(self.no_of_pre2x4):
+            for i in range(2):
+                index = pre_num * 2 + i
+
+                input_pin = self.get_pin("A[{}]".format(index))
+
+                in_name = "in[{}]".format(i)
+                decoder_pin = self.pre2x4_inst[pre_num].get_pin(in_name)
+
+                # Offset each decoder pin up so they don't conflit
+                decoder_offset = decoder_pin.center() + vector(0,i*self.m2_pitch)
+                input_offset = input_pin.center().scale(1,0) + decoder_offset.scale(0,1)
+                
+                self.connect_input_rail(decoder_offset, input_offset) 
+
+            
+        for pre_num in range(self.no_of_pre3x8):
+            for i in range(3):
+                index = pre_num * 3 + i + self.no_of_pre2x4 * 2
+                
+                input_pin = self.get_pin("A[{}]".format(index))
+
+                in_name = "in[{}]".format(i)
+                decoder_pin = self.pre3x8_inst[pre_num].get_pin(in_name)
+
+                # Offset each decoder pin up so they don't conflit
+                decoder_offset = decoder_pin.center() + vector(0,i*self.m2_pitch)
+                input_offset = input_pin.center().scale(1,0) + decoder_offset.scale(0,1)
+                
+                self.connect_input_rail(decoder_offset, input_offset) 
+    
+
+    def connect_input_rail(self, input_offset, output_offset):
+        """ Connect a vertical M2 coordinate to another vertical M2 coordinate to the predecode inputs """
+        
+        self.add_via_center(layers=("metal2", "via2", "metal3"),
+                            offset=input_offset,
+                            rotate=90)
+        self.add_via_center(layers=("metal2", "via2", "metal3"),
+                            offset=output_offset,
+                            rotate=90)
+        self.add_path(("metal3"), [input_offset, output_offset])
+
+    
     def add_pins(self):
         """ Add the module pins """
         
@@ -143,10 +205,11 @@ class hierarchical_decoder(design.design):
             debug.error("Not enough rows for a hierarchical decoder. Non-hierarchical not supported yet.",-1)
 
         # Calculates height and width of pre-decoder,
-        if(self.no_of_pre3x8 > 0):
+        if self.no_of_pre3x8 > 0:
             self.predecoder_width = self.pre3_8.width 
         else:
             self.predecoder_width = self.pre2_4.width
+            
         self.predecoder_height = self.pre2_4.height*self.no_of_pre2x4 + self.pre3_8.height*self.no_of_pre3x8
 
         # Calculates height and width of row-decoder 
@@ -154,12 +217,14 @@ class hierarchical_decoder(design.design):
             nand_width = self.nand2.width
         else:
             nand_width = self.nand3.width 
-        self.routing_width = self.metal2_pitch*self.total_number_of_predecoder_outputs
+        self.internal_routing_width = self.m2_pitch*self.total_number_of_predecoder_outputs
         self.row_decoder_height = self.inv.height * self.rows
 
+        self.input_routing_width = (self.num_inputs+1) * self.m2_pitch        
         # Calculates height and width of hierarchical decoder 
         self.height = self.row_decoder_height
-        self.width = self.predecoder_width + self.routing_width + nand_width + self.inv.width
+        self.width = self.input_routing_width + self.predecoder_width \
+            + self.internal_routing_width + nand_width + self.inv.width
 
     def create_pre_decoder(self):
         """ Creates pre-decoder and places labels input address [A] """
@@ -171,7 +236,7 @@ class hierarchical_decoder(design.design):
             self.add_pre3x8(i)
 
     def add_pre2x4(self,num):
-        """ Add a 2x4 predecoder """
+        """ Add a 2x4 predecoder to the left of the origin """
         
         if (self.num_inputs == 2):
             base = vector(-self.pre2_4.width,0)
@@ -193,27 +258,9 @@ class hierarchical_decoder(design.design):
                                                  offset=base))
         self.connect_inst(pins)
 
-        self.add_pre2x4_pins(num)
-
-                            
-
-    def add_pre2x4_pins(self,num):
-        """ Add the input pins to the 2x4 predecoder """
-
-        for i in range(2):
-            pin = self.pre2x4_inst[num].get_pin("in[{}]".format(i))
-            pin_offset = pin.ll()
-            
-            pin = self.pre2_4.get_pin("in[{}]".format(i))
-            self.add_layout_pin(text="A[{0}]".format(i + 2*num ),
-                                layer="metal2", 
-                                offset=pin_offset,
-                                width=pin.width(),
-                                height=pin.height())
-
         
     def add_pre3x8(self,num):
-        """ Add 3x8 numbered predecoder """
+        """ Add 3x8 predecoder to the left of the origin and above any 2x4 decoders """
         if (self.num_inputs == 3):
             offset = vector(-self.pre_3_8.width,0)
             mirror ="R0"
@@ -238,20 +285,6 @@ class hierarchical_decoder(design.design):
                                               offset=offset))
         self.connect_inst(pins)
 
-        # The 3x8 predecoders will be stacked, so use yoffset
-        self.add_pre3x8_pins(num,offset)
-
-    def add_pre3x8_pins(self,num,offset):
-        """ Add the input pins to the 3x8 predecoder at the given offset """
-
-        for i in range(3):            
-            pin = self.pre3x8_inst[num].get_pin("in[{}]".format(i))
-            pin_offset = pin.ll()
-            self.add_layout_pin(text="A[{0}]".format(i + 3*num + 2*self.no_of_pre2x4),
-                                layer="metal2", 
-                                offset=pin_offset,
-                                width=pin.width(),
-                                height=pin.height())
 
 
 
@@ -313,7 +346,7 @@ class hierarchical_decoder(design.design):
 
             self.nand_inst.append(self.add_inst(name=name,
                                                 mod=nand_mod,
-                                                offset=[self.routing_width, y_off],
+                                                offset=[self.internal_routing_width, y_off],
                                                 mirror=mirror))
 
             
@@ -325,9 +358,9 @@ class hierarchical_decoder(design.design):
         z_pin = self.inv.get_pin("Z")
         
         if (self.num_inputs == 4 or self.num_inputs == 5):
-            x_off = self.routing_width + self.nand2.width
+            x_off = self.internal_routing_width + self.nand2.width
         else:
-            x_off = self.routing_width + self.nand3.width
+            x_off = self.internal_routing_width + self.nand3.width
 
         self.inv_inst = []
         for row in range(self.rows):
@@ -377,7 +410,7 @@ class hierarchical_decoder(design.design):
         
 
 
-    def create_vertical_rail(self):
+    def create_predecode_rail(self):
         """ Creates vertical metal 2 rails to connect predecoder and decoder stages."""
 
         # This is not needed for inputs <4 since they have no pre/decode stages.
@@ -387,8 +420,8 @@ class hierarchical_decoder(design.design):
             self.rail_x_offsets = []
             for i in range(self.total_number_of_predecoder_outputs):
                 # The offsets go into the negative x direction
-                # assuming the predecodes are placed at (self.routing_width,0)
-                x_offset = self.metal2_pitch * i
+                # assuming the predecodes are placed at (self.internal_routing_width,0)
+                x_offset = self.m2_pitch * i
                 self.rail_x_offsets.append(x_offset+0.5*self.m2_width)
                 self.add_rect(layer="metal2",
                               offset=vector(x_offset,0),
@@ -406,7 +439,7 @@ class hierarchical_decoder(design.design):
                 index = pre_num * 4 + i
                 out_name = "out[{}]".format(i)
                 pin = self.pre2x4_inst[pre_num].get_pin(out_name)
-                self.connect_rail_m3(index, pin) 
+                self.connect_predecode_rail_m3(index, pin) 
 
             
         for pre_num in range(self.no_of_pre3x8):
@@ -414,7 +447,7 @@ class hierarchical_decoder(design.design):
                 index = pre_num * 8 + i + self.no_of_pre2x4 * 4
                 out_name = "out[{}]".format(i)
                 pin = self.pre3x8_inst[pre_num].get_pin(out_name)
-                self.connect_rail_m3(index, pin) 
+                self.connect_predecode_rail_m3(index, pin) 
             
                 
 
@@ -430,17 +463,17 @@ class hierarchical_decoder(design.design):
         if (self.num_inputs == 4 or self.num_inputs == 5):
             for index_A in self.predec_groups[0]:
                 for index_B in self.predec_groups[1]:
-                    self.connect_rail(index_A, self.nand_inst[row_index].get_pin("A"))
-                    self.connect_rail(index_B, self.nand_inst[row_index].get_pin("B"))
+                    self.connect_predecode_rail(index_A, self.nand_inst[row_index].get_pin("A"))
+                    self.connect_predecode_rail(index_B, self.nand_inst[row_index].get_pin("B"))
                     row_index = row_index + 1
 
         elif (self.num_inputs > 5):
             for index_A in self.predec_groups[0]:
                 for index_B in self.predec_groups[1]:
                     for index_C in self.predec_groups[2]:
-                        self.connect_rail(index_A, self.nand_inst[row_index].get_pin("A"))
-                        self.connect_rail(index_B, self.nand_inst[row_index].get_pin("B"))
-                        self.connect_rail(index_C, self.nand_inst[row_index].get_pin("C"))
+                        self.connect_predecode_rail(index_A, self.nand_inst[row_index].get_pin("A"))
+                        self.connect_predecode_rail(index_B, self.nand_inst[row_index].get_pin("B"))
+                        self.connect_predecode_rail(index_C, self.nand_inst[row_index].get_pin("C"))
                         row_index = row_index + 1
 
     def route_vdd_gnd(self):
@@ -476,7 +509,7 @@ class hierarchical_decoder(design.design):
             self.copy_layout_pin(pre, "gnd")
         
 
-    def connect_rail(self, rail_index, pin):
+    def connect_predecode_rail(self, rail_index, pin):
         """ Connect the routing rail to the given metal1 pin  """
         rail_pos = vector(self.rail_x_offsets[rail_index],pin.lc().y)
         self.add_path("metal1", [rail_pos, pin.lc()])
@@ -485,7 +518,7 @@ class hierarchical_decoder(design.design):
                             rotate=90)
 
 
-    def connect_rail_m3(self, rail_index, pin):
+    def connect_predecode_rail_m3(self, rail_index, pin):
         """ Connect the routing rail to the given metal1 pin  """
         mid_point = vector(pin.cx(), pin.cy()+self.inv.height/2)
         rail_pos = vector(self.rail_x_offsets[rail_index],mid_point.y)
diff --git a/compiler/modules/hierarchical_predecode.py b/compiler/modules/hierarchical_predecode.py
index e0d05d92..d111b02b 100644
--- a/compiler/modules/hierarchical_predecode.py
+++ b/compiler/modules/hierarchical_predecode.py
@@ -50,10 +50,6 @@ class hierarchical_predecode(design.design):
             debug.error("Invalid number of predecode inputs.",-1)
             
     def setup_constraints(self):
-        # use a conservative douple spacing just to get rid of annoying via DRCs
-        self.m1_pitch = max(contact.m1m2.width,contact.m1m2.height) + max(self.m1_space, self.m2_space)
-        self.m2_pitch = max(contact.m2m3.width,contact.m2m3.height) + max(self.m2_space,self.m3_space)
-        
         # The rail offsets are indexed by the label
         self.rails = {}
 
diff --git a/compiler/modules/replica_bitline.py b/compiler/modules/replica_bitline.py
index 8d1d6242..f4c8995f 100644
--- a/compiler/modules/replica_bitline.py
+++ b/compiler/modules/replica_bitline.py
@@ -53,11 +53,6 @@ class replica_bitline(design.design):
         # These aren't for instantiating, but we use them to get the dimensions
         self.poly_contact_offset = vector(0.5*contact.poly.width,0.5*contact.poly.height)
 
-        # M1/M2 routing pitch is based on contacted pitch
-        self.m1_pitch = max(contact.m1m2.width,contact.m1m2.height) + max(self.m1_space,self.m2_space)
-        self.m2_pitch = max(contact.m2m3.width,contact.m2m3.height) + max(self.m2_space,self.m3_space)
-
-        
         # Quadrant 1: Replica bitline and such are not rotated, but they must be placed far enough
         # away from the delay chain/inverter with space for three M2 tracks
         self.bitcell_offset = vector(0,self.replica_bitcell.height)
diff --git a/compiler/modules/single_level_column_mux_array.py b/compiler/modules/single_level_column_mux_array.py
index 31614ae1..777958a5 100644
--- a/compiler/modules/single_level_column_mux_array.py
+++ b/compiler/modules/single_level_column_mux_array.py
@@ -57,7 +57,6 @@ class single_level_column_mux_array(design.design):
     def setup_layout_constants(self):
         self.column_addr_size = num_of_inputs = int(self.words_per_row / 2)
         self.width = self.columns * self.mux.width
-        self.m1_pitch = contact.m1m2.width + max(drc["metal1_to_metal1"],drc["metal2_to_metal2"])
         # one set of metal1 routes for select signals and a pair to interconnect the mux outputs bl/br
         # one extra route pitch is to space from the sense amp
         self.route_height = (self.words_per_row + 3)*self.m1_pitch
diff --git a/compiler/regress.sh b/compiler/regress.sh
deleted file mode 100755
index 904ef9d8..00000000
--- a/compiler/regress.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/bin/bash
-python tests/regress.py -t freepdk45 
-python tests/regress.py -t scn3me_subm 
diff --git a/compiler/sram.py b/compiler/sram.py
index 0c144fb7..0296ad02 100644
--- a/compiler/sram.py
+++ b/compiler/sram.py
@@ -1,19 +1,17 @@
 import sys
-from tech import drc, spice
-import debug
-import design
-from math import log,sqrt,ceil
-import contact
-from bank import bank
-from dff_buf_array import dff_buf_array
-from dff_array import dff_array
 import datetime
 import getpass
+import debug
+import design
+from sram_1bank import sram_1bank
+from sram_2bank import sram_2bank
+from sram_4bank import sram_4bank
+from math import log,sqrt,ceil
 from vector import vector
 from globals import OPTS, print_time
 
     
-class sram(design.design):
+class sram(sram_1bank,sram_2bank,sram_4bank):
     """
     Dynamically generated SRAM by connecting banks to control logic. The
     number of banks should be 1 , 2 or 4
@@ -35,8 +33,8 @@ class sram(design.design):
 
         # reset the static duplicate name checker for unit tests
         # in case we create more than one SRAM
-        import design
-        design.design.name_map=[]
+        from design import design
+        design.name_map=[]
 
         self.word_size = word_size
         self.num_words = num_words
@@ -46,18 +44,20 @@ class sram(design.design):
                                                                              self.num_words))
         start_time = datetime.datetime.now()
 
-        design.design.__init__(self, name)
-
-        # M1/M2 routing pitch is based on contacted pitch of the biggest layer
-        self.m1_pitch = max(contact.m1m2.width,contact.m1m2.height) + max(self.m1_space,self.m2_space)
-        self.m2_pitch = max(contact.m2m3.width,contact.m2m3.height) + max(self.m2_space,self.m3_space)
-        self.m3_pitch = max(contact.m2m3.width,contact.m2m3.height) + max(self.m2_space,self.m3_space)
+        self.compute_sizes()
         
+        if self.num_banks == 1:
+            sram_1bank.__init__(self,name)
+        elif self.num_banks == 2:
+            sram_2bank.__init__(self,name)
+        elif self.num_banks == 4:
+            sram_4bank.__init__(self,name)
+        else:
+            debug.error("Invalid number of banks.",-1)
 
         self.control_size = 6
         self.bank_to_bus_distance = 5*self.m3_width
-        
-        self.compute_sizes()
+            
         self.create_modules()
         self.add_pins()
         self.create_layout()
@@ -109,8 +109,10 @@ class sram(design.design):
         debug.info(1,"Words per row: {}".format(self.words_per_row))
 
     def estimate_words_per_row(self,tentative_num_cols, word_size):
-        """This provides a heuristic rounded estimate for the number of words
-        per row."""
+        """
+        This provides a heuristic rounded estimate for the number of words
+        per row.
+        """
 
         if tentative_num_cols < 1.5*word_size:
             return 1
@@ -120,7 +122,8 @@ class sram(design.design):
             return 2
 
     def amend_words_per_row(self,tentative_num_rows, words_per_row):
-        """This picks the number of words per row more accurately by limiting
+        """
+        This picks the number of words per row more accurately by limiting
         it to a minimum and maximum.
         """
         # Recompute the words per row given a hard max
@@ -138,7 +141,7 @@ class sram(design.design):
         """ Add pins for entire SRAM. """
 
         for i in range(self.word_size):
-            self.add_pin("DATA[{0}]".format(i),"INOUT")
+            self.add_pin("DIN[{0}]".format(i),"INPUT")
         for i in range(self.addr_size):
             self.add_pin("ADDR[{0}]".format(i),"INPUT")
 
@@ -147,162 +150,18 @@ class sram(design.design):
         self.control_logic_outputs=self.control_logic.get_outputs()
         
         self.add_pin_list(self.control_logic_inputs,"INPUT")
+
+        for i in range(self.word_size):
+            self.add_pin("DOUT[{0}]".format(i),"OUTPUT")
+        
         self.add_pin("vdd","POWER")
         self.add_pin("gnd","GROUND")
 
+
     def create_layout(self):
-        """ Layout creation """
-        
-        if self.num_banks == 1:
-            self.add_single_bank_modules()
-            self.add_single_bank_pins()
-            self.route_single_bank()
-        elif self.num_banks == 2:
-            self.add_two_bank_modules()
-            self.route_two_banks()
-        elif self.num_banks == 4:
-            self.add_four_bank_modules()
-            self.route_four_banks()
-        else:
-            debug.error("Invalid number of banks.",-1)
-            
-
-    def add_four_bank_modules(self):
-        """ Adds the modules and the buses to the top level """
-
-        self.compute_bus_sizes()
-
-        self.add_four_banks()
-
-        self.compute_four_bank_offsets()
-
-        self.add_busses()
-
-        self.add_four_bank_logic()
-        
-        self.width = self.bank_inst[1].ur().x
-        self.height = max(self.control_logic_inst.uy(),self.msb_decoder_inst.uy())
-
-
-    def add_two_bank_modules(self):
-        """ Adds the modules and the buses to the top level """
-
-        self.compute_bus_sizes()
-
-        self.add_two_banks()
-        
-        self.compute_two_bank_offsets()
-
-        self.add_busses()
-
-        self.add_two_bank_logic()
-
-        self.width = self.bank_inst[1].ur().x
-        self.height = self.control_logic_inst.uy()
-        
-
-    def add_single_bank_modules(self):
-        """ 
-        This adds the moduels for a single bank SRAM with control
-        logic. 
-        """
-        
-        # No orientation or offset
-        self.bank_inst = self.add_bank(0, [0, 0], 1, 1)
-
-        # 3/5/18 MRG: Cannot reference positions inside submodules because boundaries
-        # are not recomputed using instance placement. So, place the control logic such that it aligns
-        # with the top of the SRAM.
-        control_pos = vector(-self.control_logic.width - self.m3_pitch,
-                             3*self.supply_rail_width)
-        self.add_control_logic(position=control_pos)
-
-        # Leave room for the control routes to the left of the flops
-        addr_pos = vector(self.control_logic_inst.lx() + 4*self.m2_pitch,
-                          control_pos.y + self.control_logic.height + self.m1_pitch)
-        self.add_addr_dff(addr_pos)
-
-        # two supply rails are already included in the bank, so just 2 here.
-        self.width = self.bank.width + self.control_logic.width + 2*self.supply_rail_pitch
-        self.height = self.bank.height 
-
-        
-    def route_shared_banks(self):
-        """ Route the shared signals for two and four bank configurations. """
-
-        # create the input control pins
-        for n in self.control_logic_inputs + ["clk"]:
-            self.copy_layout_pin(self.control_logic_inst, n)
-            
-        # connect the control logic to the control bus
-        for n in self.control_logic_outputs + ["vdd", "gnd"]:
-            pins = self.control_logic_inst.get_pins(n)
-            for pin in pins:
-                if pin.layer=="metal2":
-                    pin_pos = pin.bc()
-                    break
-            rail_pos = vector(pin_pos.x,self.horz_control_bus_positions[n].y)
-            self.add_path("metal2",[pin_pos,rail_pos])
-            self.add_via_center(("metal1","via1","metal2"),rail_pos)
-        
-        # connect the control logic cross bar
-        for n in self.control_logic_outputs:
-            cross_pos = vector(self.vert_control_bus_positions[n].x,self.horz_control_bus_positions[n].y)
-            self.add_via_center(("metal1","via1","metal2"),cross_pos)
-
-        # connect the bank select signals to the vertical bus
-        for i in range(self.num_banks):
-            pin = self.bank_inst[i].get_pin("bank_sel")
-            pin_pos = pin.rc() if i==0 else pin.lc()
-            rail_pos = vector(self.vert_control_bus_positions["bank_sel[{}]".format(i)].x,pin_pos.y)
-            self.add_path("metal3",[pin_pos,rail_pos])
-            self.add_via_center(("metal2","via2","metal3"),rail_pos)
-
-            
-    def route_four_banks(self):
-        """ Route all of the signals for the four bank SRAM. """
-        
-        self.route_shared_banks()
-
-        # connect the data output to the data bus
-        for n in self.data_bus_names:
-            for i in [0,1]:
-                pin_pos = self.bank_inst[i].get_pin(n).bc()
-                rail_pos = vector(pin_pos.x,self.data_bus_positions[n].y)
-                self.add_path("metal2",[pin_pos,rail_pos])
-                self.add_via_center(("metal2","via2","metal3"),rail_pos)
-
-            for i in [2,3]:
-                pin_pos = self.bank_inst[i].get_pin(n).uc()
-                rail_pos = vector(pin_pos.x,self.data_bus_positions[n].y)
-                self.add_path("metal2",[pin_pos,rail_pos])
-                self.add_via_center(("metal2","via2","metal3"),rail_pos)
-                
-        # route msb address bits
-        # route 2:4 decoder
-        self.route_double_msb_address()
-
-        # connect the banks to the vertical address bus
-        # connect the banks to the vertical control bus
-        for n in self.addr_bus_names + self.control_bus_names:
-            # Skip these from the horizontal bus
-            if n in ["vdd", "gnd"]: continue
-            # This will be the bank select, so skip it
-            if n in self.msb_bank_sel_addr: continue
-
-            for bank_id in [0,2]:
-                pin0_pos = self.bank_inst[bank_id].get_pin(n).rc()
-                pin1_pos = self.bank_inst[bank_id+1].get_pin(n).lc()
-                rail_pos = vector(self.vert_control_bus_positions[n].x,pin0_pos.y)
-                self.add_path("metal3",[pin0_pos,pin1_pos])
-                self.add_via_center(("metal2","via2","metal3"),rail_pos)
-            
-
-        self.route_bank_supply_rails(left_banks=[0,2], bottom_banks=[2,3])
-
-
-
-        
+        """ Layout creation """    
+        self.add_modules()
+        self.route()
 
     def compute_bus_sizes(self):
         """ Compute the independent bus widths shared between two and four bank SRAMs """
@@ -325,417 +184,70 @@ class sram(design.design):
         self.supply_bus_width = self.data_bus_width
 
         # Sanity check to ensure we can fit the control logic above a single bank (0.9 is a hack really)
-        debug.check(self.bank.width + self.vertical_bus_width > 0.9*self.control_logic.width, "Bank is too small compared to control logic.")
+        debug.check(self.bank.width + self.vertical_bus_width > 0.9*self.control_logic.width,
+                    "Bank is too small compared to control logic.")
         
         
-    def compute_four_bank_offsets(self):
-        """ Compute the overall offsets for a four bank SRAM """
-
-        # The main difference is that the four bank SRAM has the data bus in the middle of the four banks
-        # as opposed to the top of the banks.
-        
-        # In 4 bank SRAM, the height is determined by the bank decoder and address flop
-        self.vertical_bus_height = 2*self.bank.height + 4*self.bank_to_bus_distance + self.data_bus_height \
-                                   + self.supply_bus_height + self.msb_decoder.height + self.msb_address.width 
-        # The address bus extends down through the power rails, but control and bank_sel bus don't
-        self.addr_bus_height = self.vertical_bus_height
-
-        self.vertical_bus_offset = vector(self.bank.width + self.bank_to_bus_distance, 0)
-        self.data_bus_offset = vector(0, self.bank.height + self.bank_to_bus_distance)
-        self.supply_bus_offset = vector(0, self.data_bus_offset.y + self.data_bus_height + self.bank.height + 2*self.bank_to_bus_distance)        
-        self.control_bus_offset = vector(0, self.supply_bus_offset.y + self.supply_bus_height)
-        self.bank_sel_bus_offset = self.vertical_bus_offset + vector(self.m2_pitch*self.control_size,0)
-        self.addr_bus_offset = self.bank_sel_bus_offset.scale(1,0) + vector(self.m2_pitch*self.num_banks,0)
-
-        # Control is placed at the top above the control bus and everything
-        self.control_logic_position = vector(0, self.control_bus_offset.y + self.control_bus_height + self.m1_pitch)
-
-        # Bank select flops get put to the right of control logic above bank1 and the buses
-        # Leave a pitch to get the vdd rails up to M2
-        self.msb_address_position = vector(self.bank_inst[1].lx() + 3*self.supply_rail_pitch,
-                                           self.supply_bus_offset.y + self.supply_bus_height + 2*self.m1_pitch + self.msb_address.width)
-
-        # Decoder goes above the MSB address flops, and is flipped in Y
-        # separate the two by a bank to bus distance for nwell rules, just in case
-        self.msb_decoder_position = self.msb_address_position + vector(self.msb_decoder.width, self.bank_to_bus_distance)
-
-
-    def compute_two_bank_offsets(self):
-        """ Compute the overall offsets for a two bank SRAM """
-
-        # In 2 bank SRAM, the height is determined by the control bus which is higher than the msb address
-        self.vertical_bus_height = self.bank.height + 2*self.bank_to_bus_distance + self.data_bus_height + self.control_bus_height
-        # The address bus extends down through the power rails, but control and bank_sel bus don't
-        self.addr_bus_height = self.vertical_bus_height 
-        
-        self.vertical_bus_offset = vector(self.bank.width + self.bank_to_bus_distance, 0)
-        self.data_bus_offset = vector(0, self.bank.height + self.bank_to_bus_distance)
-        self.supply_bus_offset = vector(0, self.data_bus_offset.y + self.data_bus_height)        
-        self.control_bus_offset = vector(0, self.supply_bus_offset.y + self.supply_bus_height)
-        self.bank_sel_bus_offset = self.vertical_bus_offset + vector(self.m2_pitch*self.control_size,0)
-        self.addr_bus_offset = self.bank_sel_bus_offset.scale(1,0) + vector(self.m2_pitch*self.num_banks,0)
-
-        # Control is placed at the top above the control bus and everything
-        self.control_logic_position = vector(0, self.control_bus_offset.y + self.control_bus_height + self.m1_pitch)
-
-        # Bank select flops get put to the right of control logic above bank1 and the buses
-        # Leave a pitch to get the vdd rails up to M2
-        self.msb_address_position = vector(self.bank_inst[1].lx() + 3*self.supply_rail_pitch,
-                                           self.supply_bus_offset.y+self.supply_bus_height + 2*self.m1_pitch + self.msb_address.width)
         
     def add_busses(self):
         """ Add the horizontal and vertical busses """
         # Vertical bus
         # The order of the control signals on the control bus:
         self.control_bus_names = ["clk_buf", "tri_en_bar", "tri_en", "clk_buf_bar", "w_en", "s_en"]
-        self.vert_control_bus_positions = self.create_bus(layer="metal2",
-                                                          pitch=self.m2_pitch,
-                                                          offset=self.vertical_bus_offset,
-                                                          names=self.control_bus_names,
-                                                          length=self.vertical_bus_height,
-                                                          vertical=True)
+        self.vert_control_bus_positions = self.create_vertical_bus(layer="metal2",
+                                                                   pitch=self.m2_pitch,
+                                                                   offset=self.vertical_bus_offset,
+                                                                   names=self.control_bus_names,
+                                                                   length=self.vertical_bus_height)
 
         self.addr_bus_names=["A[{}]".format(i) for i in range(self.addr_size)]
-        self.vert_control_bus_positions.update(self.create_bus(layer="metal2",
-                                                               pitch=self.m2_pitch,
-                                                               offset=self.addr_bus_offset,
-                                                               names=self.addr_bus_names,
-                                                               length=self.addr_bus_height,
-                                                               vertical=True,
-                                                               make_pins=True))
+        self.vert_control_bus_positions.update(self.create_vertical_pin_bus(layer="metal2",
+                                                                            pitch=self.m2_pitch,
+                                                                            offset=self.addr_bus_offset,
+                                                                            names=self.addr_bus_names,
+                                                                            length=self.addr_bus_height))
 
         
         self.bank_sel_bus_names = ["bank_sel[{}]".format(i) for i in range(self.num_banks)]
-        self.vert_control_bus_positions.update(self.create_bus(layer="metal2",
-                                                               pitch=self.m2_pitch,
-                                                               offset=self.bank_sel_bus_offset,
-                                                               names=self.bank_sel_bus_names,
-                                                               length=self.vertical_bus_height,
-                                                               vertical=True,
-                                                               make_pins=True))
+        self.vert_control_bus_positions.update(self.create_vertical_pin_bus(layer="metal2",
+                                                                            pitch=self.m2_pitch,
+                                                                            offset=self.bank_sel_bus_offset,
+                                                                            names=self.bank_sel_bus_names,
+                                                                            length=self.vertical_bus_height))
         
 
         # Horizontal data bus
         self.data_bus_names = ["DATA[{}]".format(i) for i in range(self.word_size)]
-        self.data_bus_positions = self.create_bus(layer="metal3",
-                                                  pitch=self.m3_pitch,
-                                                  offset=self.data_bus_offset,
-                                                  names=self.data_bus_names,
-                                                  length=self.data_bus_width,
-                                                  vertical=False,
-                                                  make_pins=True)
+        self.data_bus_positions = self.create_horizontal_pin_bus(layer="metal3",
+                                                                 pitch=self.m3_pitch,
+                                                                 offset=self.data_bus_offset,
+                                                                 names=self.data_bus_names,
+                                                                 length=self.data_bus_width)
 
         # Horizontal control logic bus
         # vdd/gnd in bus go along whole SRAM
         # FIXME: Fatten these wires?
-        self.horz_control_bus_positions = self.create_bus(layer="metal1",
-                                                          pitch=self.m1_pitch,
-                                                          offset=self.supply_bus_offset,
-                                                          names=["vdd"],
-                                                          length=self.supply_bus_width,
-                                                          vertical=False)
+        self.horz_control_bus_positions = self.create_horizontal_bus(layer="metal1",
+                                                                     pitch=self.m1_pitch,
+                                                                     offset=self.supply_bus_offset,
+                                                                     names=["vdd"],
+                                                                     length=self.supply_bus_width)
         # The gnd rail must not be the entire width since we protrude the right-most vdd rail up for
         # the decoder in 4-bank SRAMs
-        self.horz_control_bus_positions.update(self.create_bus(layer="metal1",
-                                                               pitch=self.m1_pitch,
-                                                               offset=self.supply_bus_offset+vector(0,self.m1_pitch),
-                                                               names=["gnd"],
-                                                               length=self.supply_bus_width,
-                                                               vertical=False))
-        self.horz_control_bus_positions.update(self.create_bus(layer="metal1",
-                                                               pitch=self.m1_pitch,
-                                                               offset=self.control_bus_offset,
-                                                               names=self.control_bus_names,
-                                                               length=self.control_bus_width,
-                                                               vertical=False))
-        
-    def add_two_bank_logic(self):
-        """ Add the control and MSB logic """
-
-        self.add_control_logic(position=self.control_logic_position)
-
-        self.msb_address_inst = self.add_inst(name="msb_address",
-                                              mod=self.msb_address,
-                                              offset=self.msb_address_position,
-                                              rotate=270)
-        self.msb_bank_sel_addr = "ADDR[{}]".format(self.addr_size-1)
-        self.connect_inst([self.msb_bank_sel_addr,"bank_sel[1]","bank_sel[0]","clk_buf", "vdd", "gnd"])
-
-    def add_four_bank_logic(self):
-        """ Add the control and MSB decode/bank select logic for four banks """
-
-
-        self.add_control_logic(position=self.control_logic_position)
-
-        self.msb_address_inst = self.add_inst(name="msb_address",
-                                              mod=self.msb_address,
-                                              offset=self.msb_address_position,
-                                              rotate=270)
-
-        self.msb_bank_sel_addr = ["ADDR[{}]".format(i) for i in range(self.addr_size-2,self.addr_size,1)]        
-        temp = list(self.msb_bank_sel_addr)
-        temp.extend(["msb{0}[{1}]".format(j,i) for i in range(2) for j in ["","_bar"]])
-        temp.extend(["clk_buf", "vdd", "gnd"])
-        self.connect_inst(temp)
-        
-        self.msb_decoder_inst = self.add_inst(name="msb_decoder",
-                                              mod=self.msb_decoder,
-                                              offset=self.msb_decoder_position,
-                                              mirror="MY")
-        temp = ["msb[{}]".format(i) for i in range(2)]
-        temp.extend(["bank_sel[{}]".format(i) for i in range(4)])
-        temp.extend(["vdd", "gnd"])
-        self.connect_inst(temp)
-        
-        
-    def route_two_banks(self):
-        """ Route all of the signals for the two bank SRAM. """
-
-        self.route_shared_banks()
-            
-        # connect the horizontal control bus to the vertical bus
-        # connect the data output to the data bus
-        for n in self.data_bus_names:
-            for i in [0,1]:
-                pin_pos = self.bank_inst[i].get_pin(n).uc()
-                rail_pos = vector(pin_pos.x,self.data_bus_positions[n].y)
-                self.add_path("metal2",[pin_pos,rail_pos])
-                self.add_via_center(("metal2","via2","metal3"),rail_pos)
-
-        self.route_single_msb_address()
-
-        # connect the banks to the vertical address bus
-        # connect the banks to the vertical control bus
-        for n in self.addr_bus_names + self.control_bus_names:
-            # Skip these from the horizontal bus
-            if n in ["vdd", "gnd"]: continue
-            # This will be the bank select, so skip it
-            if n == self.msb_bank_sel_addr: continue
-            pin0_pos = self.bank_inst[0].get_pin(n).rc()
-            pin1_pos = self.bank_inst[1].get_pin(n).lc()
-            rail_pos = vector(self.vert_control_bus_positions[n].x,pin0_pos.y)
-            self.add_path("metal3",[pin0_pos,pin1_pos])
-            self.add_via_center(("metal2","via2","metal3"),rail_pos)
-
+        self.horz_control_bus_positions.update(self.create_horizontal_bus(layer="metal1",
+                                                                          pitch=self.m1_pitch,
+                                                                          offset=self.supply_bus_offset+vector(0,self.m1_pitch),
+                                                                          names=["gnd"],
+                                                                          length=self.supply_bus_width))
+        self.horz_control_bus_positions.update(self.create_horizontal_bus(layer="metal1",
+                                                                          pitch=self.m1_pitch,
+                                                                          offset=self.control_bus_offset,
+                                                                          names=self.control_bus_names,
+                                                                          length=self.control_bus_width))
 
         
-    def route_double_msb_address(self):
-        """ Route two MSB address bits and the bank decoder for 4-bank SRAM """
 
-        # connect the MSB flops to the address input bus
-        for i in [0,1]:
-            msb_pins = self.msb_address_inst.get_pins("din[{}]".format(i))
-            for msb_pin in msb_pins:
-                if msb_pin.layer == "metal3":
-                    msb_pin_pos = msb_pin.lc()
-                    break
-            rail_pos = vector(self.vert_control_bus_positions[self.msb_bank_sel_addr[i]].x,msb_pin_pos.y)
-            self.add_path("metal3",[msb_pin_pos,rail_pos])
-            self.add_via_center(("metal2","via2","metal3"),rail_pos)
         
-        # Connect clk
-        clk_pin = self.msb_address_inst.get_pin("clk")
-        clk_pos = clk_pin.bc()
-        rail_pos = self.horz_control_bus_positions["clk_buf"]
-        bend_pos = vector(clk_pos.x,self.horz_control_bus_positions["clk_buf"].y)
-        self.add_path("metal1",[clk_pos,bend_pos,rail_pos])
-
-        # Connect bank decoder outputs to the bank select vertical bus wires
-        for i in range(self.num_banks):
-            msb_pin = self.msb_decoder_inst.get_pin("out[{}]".format(i))
-            msb_pin_pos = msb_pin.lc()
-            rail_pos = vector(self.vert_control_bus_positions["bank_sel[{}]".format(i)].x,msb_pin_pos.y)
-            self.add_path("metal1",[msb_pin_pos,rail_pos])
-            self.add_via_center(("metal1","via1","metal2"),rail_pos)
-
-        # connect MSB flop outputs to the bank decoder inputs
-        msb_pin = self.msb_address_inst.get_pin("dout[0]")
-        msb_pin_pos = msb_pin.rc()
-        in_pin = self.msb_decoder_inst.get_pin("in[0]")
-        in_pos = in_pin.bc() + vector(0,1*self.m2_pitch,) # pin is up from bottom
-        out_pos = msb_pin_pos + vector(1*self.m2_pitch,0) # route out to the right
-        up_pos = vector(out_pos.x,in_pos.y) # and route up to the decoer
-        self.add_wire(("metal1","via1","metal2"),[msb_pin_pos,out_pos,up_pos,in_pos])
-        self.add_via_center(("metal1","via1","metal2"),in_pos)
-        self.add_via_center(("metal1","via1","metal2"),msb_pin_pos,rotate=90)
-            
-        msb_pin = self.msb_address_inst.get_pin("dout[1]")
-        msb_pin_pos = msb_pin.rc()
-        in_pin = self.msb_decoder_inst.get_pin("in[1]")
-        in_pos = in_pin.bc() + vector(0,self.bitcell.height+self.m2_pitch) # route the next row up
-        out_pos = msb_pin_pos + vector(2*self.m2_pitch,0) # route out to the right
-        up_pos = vector(out_pos.x,in_pos.y) # and route up to the decoer
-        self.add_wire(("metal1","via1","metal2"),[msb_pin_pos,out_pos,up_pos,in_pos])
-        self.add_via_center(("metal1","via1","metal2"),in_pos)
-        self.add_via_center(("metal1","via1","metal2"),msb_pin_pos,rotate=90)
-
-        self.route_double_msb_address_supplies()
-        
-    def route_double_msb_address_supplies(self):
-        """ Route the vdd/gnd bits of the 2-bit bank decoder. """
-        
-        # Route the right-most vdd/gnd of the right upper bank to the top of the decoder
-        vdd_pins = self.bank_inst[1].get_pins("vdd")
-        left_bank_vdd_pin = None
-        right_bank_vdd_pin = None
-        for vdd_pin in vdd_pins:
-            if vdd_pin.layer != "metal2":
-                continue
-            if left_bank_vdd_pin == None or vdd_pin.lx()<left_bank_vdd_pin.lx():
-                left_bank_vdd_pin = vdd_pin
-            if right_bank_vdd_pin == None or vdd_pin.lx()>right_bank_vdd_pin.lx():
-                right_bank_vdd_pin = vdd_pin
-            # Route to top
-            self.add_rect(layer="metal2",
-                          offset=vdd_pin.ul(),
-                          height=self.height-vdd_pin.uy(),
-                          width=vdd_pin.width())
-
-        gnd_pins = self.bank_inst[1].get_pins("gnd")
-        left_bank_gnd_pin = None
-        right_bank_gnd_pin = None
-        for gnd_pin in gnd_pins:
-            if gnd_pin.layer != "metal2":
-                continue
-            if left_bank_gnd_pin == None or gnd_pin.lx()<left_bank_gnd_pin.lx():
-                left_bank_gnd_pin = gnd_pin
-            if right_bank_gnd_pin == None or gnd_pin.lx()>right_bank_gnd_pin.lx():
-                right_bank_gnd_pin = gnd_pin
-            # Route to top
-            self.add_rect(layer="metal2",
-                          offset=gnd_pin.ul(),
-                          height=self.height-gnd_pin.uy(),
-                          width=gnd_pin.width())
-        
-        # Connect bank decoder vdd/gnd supplies using the previous bank pins
-        vdd_pins = self.msb_decoder_inst.get_pins("vdd")
-        for vdd_pin in vdd_pins:
-            if vdd_pin.layer != "metal1":
-                continue
-            rail1_pos = vector(left_bank_vdd_pin.cx(),vdd_pin.cy())
-            rail2_pos = vector(right_bank_vdd_pin.cx(),vdd_pin.cy())
-            self.add_path("metal1",[rail1_pos,rail2_pos])
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=rail1_pos,
-                                rotate=90,
-                                size=[1,3])
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=rail2_pos,
-                                rotate=90,
-                                size=[1,3])
-        gnd_pins = self.msb_decoder_inst.get_pins("gnd")
-        for gnd_pin in gnd_pins:
-            if gnd_pin.layer != "metal1":
-                continue
-            rail1_pos = vector(left_bank_gnd_pin.cx(),gnd_pin.cy())
-            rail2_pos = vector(right_bank_gnd_pin.cx(),gnd_pin.cy())
-            self.add_path("metal1",[rail1_pos,rail2_pos])
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=rail1_pos,
-                                rotate=90,
-                                size=[1,3])
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=rail2_pos,
-                                rotate=90,
-                                size=[1,3])
-        
-        # connect the bank MSB flop supplies
-        vdd_pins = self.msb_address_inst.get_pins("vdd")
-        # vdd pins go down to the rail
-        for vdd_pin in vdd_pins:
-            if vdd_pin.layer != "metal1":
-                continue
-            vdd_pos = vdd_pin.bc()
-            down_pos = vdd_pos - vector(0,self.m1_pitch)
-            rail_pos = vector(vdd_pos.x,self.horz_control_bus_positions["vdd"].y)
-            self.add_path("metal1",[vdd_pos,down_pos])            
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=down_pos,
-                                rotate=90)   
-            self.add_path("metal2",[down_pos,rail_pos])
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=rail_pos)        
-        # gnd pins go right to the rail
-        gnd_pins = self.msb_address_inst.get_pins("gnd")
-        for gnd_pin in gnd_pins:
-            if gnd_pin.layer != "metal2":
-                continue
-            rail1_pos = vector(left_bank_gnd_pin.cx(),gnd_pin.cy())
-            self.add_path("metal1",[rail1_pos,gnd_pin.lc()])
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=gnd_pin.lc(),
-                                rotate=90)
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                         offset=rail1_pos,
-                         rotate=90,
-                         size=[1,3])            
-        
-    def route_single_msb_address(self):
-        """ Route one MSB address bit for 2-bank SRAM """
-        
-        # connect the bank MSB flop supplies
-        vdd_pins = self.msb_address_inst.get_pins("vdd")
-        for vdd_pin in vdd_pins:
-            if vdd_pin.layer != "metal1": continue
-            vdd_pos = vdd_pin.bc()
-            down_pos = vdd_pos - vector(0,self.m1_pitch)
-            rail_pos = vector(vdd_pos.x,self.horz_control_bus_positions["vdd"].y)
-            self.add_path("metal1",[vdd_pos,down_pos])            
-            self.add_via_center(("metal1","via1","metal2"),down_pos,rotate=90)   
-            self.add_path("metal2",[down_pos,rail_pos])
-            self.add_via_center(("metal1","via1","metal2"),rail_pos)
-        
-        gnd_pins = self.msb_address_inst.get_pins("gnd")
-        # Only add the ground connection to the lowest metal2 rail in the flop array
-        # FIXME: SCMOS doesn't have a vertical rail in the cell, or we could use those
-        lowest_y = None
-        for gnd_pin in gnd_pins:
-            if gnd_pin.layer != "metal2": continue
-            if lowest_y==None or gnd_pin.by()<lowest_y:
-                lowest_y=gnd_pin.by()
-                gnd_pos = gnd_pin.ur()
-        rail_pos = vector(gnd_pos.x,self.horz_control_bus_positions["gnd"].y)
-        self.add_path("metal2",[gnd_pos,rail_pos])
-        self.add_via_center(("metal1","via1","metal2"),rail_pos)            
-        
-        # connect the MSB flop to the address input bus 
-        msb_pins = self.msb_address_inst.get_pins("din[0]")
-        for msb_pin in msb_pins:
-            if msb_pin.layer == "metal3":
-                msb_pin_pos = msb_pin.lc()
-                break
-        rail_pos = vector(self.vert_control_bus_positions[self.msb_bank_sel_addr].x,msb_pin_pos.y)
-        self.add_path("metal3",[msb_pin_pos,rail_pos])
-        self.add_via_center(("metal2","via2","metal3"),rail_pos)
-
-        # Connect the output bar to select 0
-        msb_out_pin = self.msb_address_inst.get_pin("dout_bar[0]")
-        msb_out_pos = msb_out_pin.rc()
-        out_extend_right_pos = msb_out_pos + vector(2*self.m2_pitch,0)
-        out_extend_up_pos = out_extend_right_pos + vector(0,self.m2_width)
-        rail_pos = vector(self.vert_control_bus_positions["bank_sel[0]"].x,out_extend_up_pos.y)
-        self.add_path("metal2",[msb_out_pos,out_extend_right_pos,out_extend_up_pos])
-        self.add_wire(("metal3","via2","metal2"),[out_extend_right_pos,out_extend_up_pos,rail_pos])
-        self.add_via_center(("metal2","via2","metal3"),rail_pos)
-        
-        # Connect the output to select 1
-        msb_out_pin = self.msb_address_inst.get_pin("dout[0]")
-        msb_out_pos = msb_out_pin.rc()
-        out_extend_right_pos = msb_out_pos + vector(2*self.m2_pitch,0)
-        out_extend_down_pos = out_extend_right_pos - vector(0,2*self.m1_pitch)
-        rail_pos = vector(self.vert_control_bus_positions["bank_sel[1]"].x,out_extend_down_pos.y)
-        self.add_path("metal2",[msb_out_pos,out_extend_right_pos,out_extend_down_pos])
-        self.add_wire(("metal3","via2","metal2"),[out_extend_right_pos,out_extend_down_pos,rail_pos])
-        self.add_via_center(("metal2","via2","metal3"),rail_pos)
-        
-        # Connect clk
-        clk_pin = self.msb_address_inst.get_pin("clk")
-        clk_pos = clk_pin.bc()
-        rail_pos = self.horz_control_bus_positions["clk_buf"]
-        bend_pos = vector(clk_pos.x,self.horz_control_bus_positions["clk_buf"].y)
-        self.add_path("metal1",[clk_pos,bend_pos,rail_pos])
-        
-
 
     def route_vdd_gnd(self):
         """ Propagate all vdd/gnd pins up to this level for all modules """
@@ -768,7 +280,7 @@ class sram(design.design):
         
     def create_multi_bank_modules(self):
         """ Create the multibank address flops and bank decoder """
-        
+        from dff_buf_array import dff_buf_array
         self.msb_address = dff_buf_array(name="msb_address",
                                          rows=1,
                                          columns=self.num_banks/2)
@@ -781,16 +293,19 @@ class sram(design.design):
     def create_modules(self):
         """ Create all the modules that will be used """
 
+        from control_logic import control_logic
         # Create the control logic module
         self.control_logic = self.mod_control_logic(num_rows=self.num_rows)
         self.add_mod(self.control_logic)
 
         # Create the address and control flops (but not the clk)
         dff_size = self.addr_size
+        from dff_array import dff_array
         self.addr_dff = dff_array(name="dff_array", rows=dff_size, columns=1)
         self.add_mod(self.addr_dff)
         
         # Create the bank module (up to four are instantiated)
+        from bank import bank
         self.bank = bank(word_size=self.word_size,
                          num_words=self.num_words_per_bank,
                          words_per_row=self.words_per_row,
@@ -854,44 +369,6 @@ class sram(design.design):
 
         return bank_inst
 
-    # FIXME: This should be in geometry.py or it's own class since it is
-    # reusable
-    def create_bus(self, layer, pitch, offset, names, length, vertical=False, make_pins=False):
-        """ Create a horizontal or vertical bus. It can be either just rectangles, or actual
-        layout pins. It returns an map of line center line positions indexed by name.  """
-
-        # half minwidth so we can return the center line offsets
-        half_minwidth = 0.5*drc["minwidth_{}".format(layer)]
-        
-        line_positions = {}
-        if vertical:
-            for i in range(len(names)):
-                line_offset = offset + vector(i*pitch,0)
-                if make_pins:
-                    self.add_layout_pin(text=names[i],
-                                        layer=layer,
-                                        offset=line_offset,
-                                        height=length)
-                else:
-                    self.add_rect(layer=layer,
-                                  offset=line_offset,
-                                  height=length)
-                line_positions[names[i]]=line_offset+vector(half_minwidth,0)
-        else:
-            for i in range(len(names)):
-                line_offset = offset + vector(0,i*pitch + half_minwidth)
-                if make_pins:
-                    self.add_layout_pin(text=names[i],
-                                        layer=layer,
-                                        offset=line_offset,
-                                        width=length)
-                else:
-                    self.add_rect(layer=layer,
-                                  offset=line_offset,
-                                  width=length)
-                line_positions[names[i]]=line_offset+vector(0,half_minwidth)
-
-        return line_positions
 
 
     def add_addr_dff(self, position):
@@ -939,51 +416,9 @@ class sram(design.design):
                            layer="metal2",  
                            offset=self.vert_control_bus_positions[n])
 
-    def add_single_bank_pins(self):
-        """
-        Add the top-level pins for a single bank SRAM with control.
-        """
-
-        for i in range(self.word_size):
-            self.copy_layout_pin(self.bank_inst, "DOUT[{}]".format(i))
-            
-        for i in range(self.addr_size):
-            self.copy_layout_pin(self.addr_dff_inst, "din[{}]".format(i),"ADDR[{}]".format(i))
 
 
-    def add_two_banks(self):
-        # Placement of bank 0 (left)
-        bank_position_0 = vector(self.bank.width,
-                                 self.bank.height)
-        self.bank_inst=[self.add_bank(0, bank_position_0, -1, -1)]
 
-        # Placement of bank 1 (right)
-        x_off = self.bank.width + self.vertical_bus_width + 2*self.bank_to_bus_distance
-        bank_position_1 = vector(x_off, bank_position_0.y)
-        self.bank_inst.append(self.add_bank(1, bank_position_1, -1, 1))
-
-
-    def add_four_banks(self):
-        
-        # Placement of bank 0 (upper left)
-        bank_position_0 = vector(self.bank.width,
-                                 self.bank.height + self.data_bus_height + 2*self.bank_to_bus_distance)
-        self.bank_inst=[self.add_bank(0, bank_position_0, 1, -1)]
-
-        # Placement of bank 1 (upper right)
-        x_off = self.bank.width + self.vertical_bus_width + 2*self.bank_to_bus_distance
-        bank_position_1 = vector(x_off, bank_position_0.y)
-        self.bank_inst.append(self.add_bank(1, bank_position_1, 1, 1))
-
-        # Placement of bank 2 (bottom left)
-        y_off = self.bank.height
-        bank_position_2 = vector(bank_position_0.x, y_off)
-        self.bank_inst.append(self.add_bank(2, bank_position_2, -1, -1))
-
-        # Placement of bank 3 (bottom right)
-        bank_position_3 = vector(bank_position_1.x, bank_position_2.y)
-        self.bank_inst.append(self.add_bank(3, bank_position_3, -1, 1))
-        
 
     def connect_rail_from_left_m2m3(self, src_pin, dest_pin):
         """ Helper routine to connect an unrotated/mirrored oriented instance to the rails """
@@ -1000,49 +435,6 @@ class sram(design.design):
         out_pos = vector(dest_pin.cx(), in_pos.y)
         self.add_wire(("metal2","via1","metal1"),[in_pos, out_pos, out_pos - vector(0,self.m2_pitch)])
 
-    def route_single_bank(self):
-        """ Route a single bank SRAM """
-
-        # Route the outputs from the control logic module
-        for n in self.control_logic_outputs:
-            src_pin = self.control_logic_inst.get_pin(n)
-            dest_pin = self.bank_inst.get_pin(n)                
-            self.connect_rail_from_left_m2m3(src_pin, dest_pin)
-            self.add_via_center(layers=("metal1","via1","metal2"),
-                                offset=src_pin.rc(),
-                                rotate=90)
-            
-
-        # Connect the output of the flops to the bank pins
-        for i in range(self.addr_size):
-            flop_name = "dout[{}]".format(i)
-            bank_name = "A[{}]".format(i)
-            flop_pin = self.addr_dff_inst.get_pin(flop_name)
-            bank_pin = self.bank_inst.get_pin(bank_name)
-            flop_pos = flop_pin.center()
-            bank_pos = vector(bank_pin.cx(),flop_pos.y)
-            self.add_path("metal3",[flop_pos, bank_pos])
-            self.add_via_center(layers=("metal2","via2","metal3"),
-                                offset=flop_pos,
-                                rotate=90)
-            self.add_via_center(layers=("metal2","via2","metal3"),
-                                offset=bank_pos,
-                                rotate=90)
-
-        # Connect the control pins as inputs
-        for n in self.control_logic_inputs + ["clk"]:
-            self.copy_layout_pin(self.control_logic_inst, n)
-
-        # Connect the clock between the flops and control module
-        flop_pin = self.addr_dff_inst.get_pin("clk")
-        ctrl_pin = self.control_logic_inst.get_pin("clk_buf")
-        flop_pos = flop_pin.uc()
-        ctrl_pos = ctrl_pin.bc()
-        mid_ypos = 0.5*(ctrl_pos.y+flop_pos.y)
-        mid1_pos = vector(flop_pos.x, mid_ypos)
-        mid2_pos = vector(ctrl_pos.x, mid_ypos)                
-        self.add_wire(("metal1","via1","metal2"),[flop_pin.uc(), mid1_pos, mid2_pos, ctrl_pin.bc()])  
-
         
 
     def sp_write(self, sp_name):
diff --git a/compiler/sram_1bank.py b/compiler/sram_1bank.py
new file mode 100644
index 00000000..c1ee4c0f
--- /dev/null
+++ b/compiler/sram_1bank.py
@@ -0,0 +1,101 @@
+import sys
+from tech import drc, spice
+import debug
+from math import log,sqrt,ceil
+import datetime
+import getpass
+from vector import vector
+from globals import OPTS, print_time
+
+from design import design
+from bank import bank
+from dff_buf_array import dff_buf_array
+from dff_array import dff_array
+
+
+class sram_1bank(design):
+    """
+    Procedures specific to a two bank SRAM.
+    """
+    def __init__(self, name):
+        design.__init__(self, name)
+
+    def add_modules(self):
+        """ 
+        This adds the moduels for a single bank SRAM with control
+        logic. 
+        """
+        
+        # No orientation or offset
+        self.bank_inst = self.add_bank(0, [0, 0], 1, 1)
+
+        # 3/5/18 MRG: Cannot reference positions inside submodules because boundaries
+        # are not recomputed using instance placement. So, place the control logic such that it aligns
+        # with the top of the SRAM.
+        control_pos = vector(-self.control_logic.width - self.m3_pitch,
+                             3*self.supply_rail_width)
+        self.add_control_logic(position=control_pos)
+
+        # Leave room for the control routes to the left of the flops
+        addr_pos = vector(self.control_logic_inst.lx() + 4*self.m2_pitch,
+                          control_pos.y + self.control_logic.height + self.m1_pitch)
+        self.add_addr_dff(addr_pos)
+
+        # two supply rails are already included in the bank, so just 2 here.
+        self.width = self.bank.width + self.control_logic.width + 2*self.supply_rail_pitch
+        self.height = self.bank.height 
+
+    def add_pins(self):
+        """
+        Add the top-level pins for a single bank SRAM with control.
+        """
+
+        for i in range(self.word_size):
+            self.copy_layout_pin(self.bank_inst, "DOUT[{}]".format(i))
+            
+        for i in range(self.addr_size):
+            self.copy_layout_pin(self.addr_dff_inst, "din[{}]".format(i),"ADDR[{}]".format(i))
+        
+    def route(self):
+        """ Route a single bank SRAM """
+
+        # Route the outputs from the control logic module
+        for n in self.control_logic_outputs:
+            src_pin = self.control_logic_inst.get_pin(n)
+            dest_pin = self.bank_inst.get_pin(n)                
+            self.connect_rail_from_left_m2m3(src_pin, dest_pin)
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=src_pin.rc(),
+                                rotate=90)
+            
+
+        # Connect the output of the flops to the bank pins
+        for i in range(self.addr_size):
+            flop_name = "dout[{}]".format(i)
+            bank_name = "A[{}]".format(i)
+            flop_pin = self.addr_dff_inst.get_pin(flop_name)
+            bank_pin = self.bank_inst.get_pin(bank_name)
+            flop_pos = flop_pin.center()
+            bank_pos = vector(bank_pin.cx(),flop_pos.y)
+            self.add_path("metal3",[flop_pos, bank_pos])
+            self.add_via_center(layers=("metal2","via2","metal3"),
+                                offset=flop_pos,
+                                rotate=90)
+            self.add_via_center(layers=("metal2","via2","metal3"),
+                                offset=bank_pos,
+                                rotate=90)
+
+        # Connect the control pins as inputs
+        for n in self.control_logic_inputs + ["clk"]:
+            self.copy_layout_pin(self.control_logic_inst, n)
+
+        # Connect the clock between the flops and control module
+        flop_pin = self.addr_dff_inst.get_pin("clk")
+        ctrl_pin = self.control_logic_inst.get_pin("clk_buf")
+        flop_pos = flop_pin.uc()
+        ctrl_pos = ctrl_pin.bc()
+        mid_ypos = 0.5*(ctrl_pos.y+flop_pos.y)
+        mid1_pos = vector(flop_pos.x, mid_ypos)
+        mid2_pos = vector(ctrl_pos.x, mid_ypos)                
+        self.add_wire(("metal1","via1","metal2"),[flop_pin.uc(), mid1_pos, mid2_pos, ctrl_pin.bc()])  
+
diff --git a/compiler/sram_2bank.py b/compiler/sram_2bank.py
new file mode 100644
index 00000000..531d9963
--- /dev/null
+++ b/compiler/sram_2bank.py
@@ -0,0 +1,216 @@
+import sys
+from tech import drc, spice
+import debug
+import design
+from math import log,sqrt,ceil
+import contact
+from bank import bank
+from dff_buf_array import dff_buf_array
+from dff_array import dff_array
+import datetime
+import getpass
+from vector import vector
+from globals import OPTS, print_time
+
+class sram_2bank(design.design):
+    """
+    Procedures specific to a two bank SRAM.
+    """
+    def __init__(self, name):
+        design.__init__(self, name)
+
+    def compute_bank_offsets(self):
+        """ Compute the overall offsets for a two bank SRAM """
+
+        # In 2 bank SRAM, the height is determined by the control bus which is higher than the msb address
+        self.vertical_bus_height = self.bank.height + 2*self.bank_to_bus_distance + self.data_bus_height + self.control_bus_height
+        # The address bus extends down through the power rails, but control and bank_sel bus don't
+        self.addr_bus_height = self.vertical_bus_height 
+        
+        self.vertical_bus_offset = vector(self.bank.width + self.bank_to_bus_distance, 0)
+        self.data_bus_offset = vector(0, self.bank.height + self.bank_to_bus_distance)
+        self.supply_bus_offset = vector(0, self.data_bus_offset.y + self.data_bus_height)        
+        self.control_bus_offset = vector(0, self.supply_bus_offset.y + self.supply_bus_height)
+        self.bank_sel_bus_offset = self.vertical_bus_offset + vector(self.m2_pitch*self.control_size,0)
+        self.addr_bus_offset = self.bank_sel_bus_offset.scale(1,0) + vector(self.m2_pitch*self.num_banks,0)
+
+        # Control is placed at the top above the control bus and everything
+        self.control_logic_position = vector(0, self.control_bus_offset.y + self.control_bus_height + self.m1_pitch)
+
+        # Bank select flops get put to the right of control logic above bank1 and the buses
+        # Leave a pitch to get the vdd rails up to M2
+        self.msb_address_position = vector(self.bank_inst[1].lx() + 3*self.supply_rail_pitch,
+                                           self.supply_bus_offset.y + self.supply_bus_height \
+                                           + 2*self.m1_pitch + self.msb_address.width)
+    
+    def add_modules(self):
+        """ Adds the modules and the buses to the top level """
+
+        self.compute_bus_sizes()
+
+        self.add_banks()
+        
+        self.compute_bank_offsets()
+
+        self.add_busses()
+
+        self.add_logic()
+
+        self.width = self.bank_inst[1].ur().x
+        self.height = self.control_logic_inst.uy()
+
+
+
+    def add_banks(self):
+        # Placement of bank 0 (left)
+        bank_position_0 = vector(self.bank.width,
+                                 self.bank.height)
+        self.bank_inst=[self.add_bank(0, bank_position_0, -1, -1)]
+
+        # Placement of bank 1 (right)
+        x_off = self.bank.width + self.vertical_bus_width + 2*self.bank_to_bus_distance
+        bank_position_1 = vector(x_off, bank_position_0.y)
+        self.bank_inst.append(self.add_bank(1, bank_position_1, -1, 1))
+
+    def add_logic(self):
+        """ Add the control and MSB logic """
+
+        self.add_control_logic(position=self.control_logic_position)
+
+        self.msb_address_inst = self.add_inst(name="msb_address",
+                                              mod=self.msb_address,
+                                              offset=self.msb_address_position,
+                                              rotate=270)
+        self.msb_bank_sel_addr = "ADDR[{}]".format(self.addr_size-1)
+        self.connect_inst([self.msb_bank_sel_addr,"bank_sel[1]","bank_sel[0]","clk_buf", "vdd", "gnd"])
+        
+
+    def route_shared_banks(self):
+        """ Route the shared signals for two and four bank configurations. """
+
+        # create the input control pins
+        for n in self.control_logic_inputs + ["clk"]:
+            self.copy_layout_pin(self.control_logic_inst, n)
+            
+        # connect the control logic to the control bus
+        for n in self.control_logic_outputs + ["vdd", "gnd"]:
+            pins = self.control_logic_inst.get_pins(n)
+            for pin in pins:
+                if pin.layer=="metal2":
+                    pin_pos = pin.bc()
+                    break
+            rail_pos = vector(pin_pos.x,self.horz_control_bus_positions[n].y)
+            self.add_path("metal2",[pin_pos,rail_pos])
+            self.add_via_center(("metal1","via1","metal2"),rail_pos)
+        
+        # connect the control logic cross bar
+        for n in self.control_logic_outputs:
+            cross_pos = vector(self.vert_control_bus_positions[n].x,self.horz_control_bus_positions[n].y)
+            self.add_via_center(("metal1","via1","metal2"),cross_pos)
+
+        # connect the bank select signals to the vertical bus
+        for i in range(self.num_banks):
+            pin = self.bank_inst[i].get_pin("bank_sel")
+            pin_pos = pin.rc() if i==0 else pin.lc()
+            rail_pos = vector(self.vert_control_bus_positions["bank_sel[{}]".format(i)].x,pin_pos.y)
+            self.add_path("metal3",[pin_pos,rail_pos])
+            self.add_via_center(("metal2","via2","metal3"),rail_pos)
+
+    def route_single_msb_address(self):
+        """ Route one MSB address bit for 2-bank SRAM """
+        
+        # connect the bank MSB flop supplies
+        vdd_pins = self.msb_address_inst.get_pins("vdd")
+        for vdd_pin in vdd_pins:
+            if vdd_pin.layer != "metal1": continue
+            vdd_pos = vdd_pin.bc()
+            down_pos = vdd_pos - vector(0,self.m1_pitch)
+            rail_pos = vector(vdd_pos.x,self.horz_control_bus_positions["vdd"].y)
+            self.add_path("metal1",[vdd_pos,down_pos])            
+            self.add_via_center(("metal1","via1","metal2"),down_pos,rotate=90)   
+            self.add_path("metal2",[down_pos,rail_pos])
+            self.add_via_center(("metal1","via1","metal2"),rail_pos)
+        
+        gnd_pins = self.msb_address_inst.get_pins("gnd")
+        # Only add the ground connection to the lowest metal2 rail in the flop array
+        # FIXME: SCMOS doesn't have a vertical rail in the cell, or we could use those
+        lowest_y = None
+        for gnd_pin in gnd_pins:
+            if gnd_pin.layer != "metal2": continue
+            if lowest_y==None or gnd_pin.by()<lowest_y:
+                lowest_y=gnd_pin.by()
+                gnd_pos = gnd_pin.ur()
+        rail_pos = vector(gnd_pos.x,self.horz_control_bus_positions["gnd"].y)
+        self.add_path("metal2",[gnd_pos,rail_pos])
+        self.add_via_center(("metal1","via1","metal2"),rail_pos)            
+        
+        # connect the MSB flop to the address input bus 
+        msb_pins = self.msb_address_inst.get_pins("din[0]")
+        for msb_pin in msb_pins:
+            if msb_pin.layer == "metal3":
+                msb_pin_pos = msb_pin.lc()
+                break
+        rail_pos = vector(self.vert_control_bus_positions[self.msb_bank_sel_addr].x,msb_pin_pos.y)
+        self.add_path("metal3",[msb_pin_pos,rail_pos])
+        self.add_via_center(("metal2","via2","metal3"),rail_pos)
+
+        # Connect the output bar to select 0
+        msb_out_pin = self.msb_address_inst.get_pin("dout_bar[0]")
+        msb_out_pos = msb_out_pin.rc()
+        out_extend_right_pos = msb_out_pos + vector(2*self.m2_pitch,0)
+        out_extend_up_pos = out_extend_right_pos + vector(0,self.m2_width)
+        rail_pos = vector(self.vert_control_bus_positions["bank_sel[0]"].x,out_extend_up_pos.y)
+        self.add_path("metal2",[msb_out_pos,out_extend_right_pos,out_extend_up_pos])
+        self.add_wire(("metal3","via2","metal2"),[out_extend_right_pos,out_extend_up_pos,rail_pos])
+        self.add_via_center(("metal2","via2","metal3"),rail_pos)
+        
+        # Connect the output to select 1
+        msb_out_pin = self.msb_address_inst.get_pin("dout[0]")
+        msb_out_pos = msb_out_pin.rc()
+        out_extend_right_pos = msb_out_pos + vector(2*self.m2_pitch,0)
+        out_extend_down_pos = out_extend_right_pos - vector(0,2*self.m1_pitch)
+        rail_pos = vector(self.vert_control_bus_positions["bank_sel[1]"].x,out_extend_down_pos.y)
+        self.add_path("metal2",[msb_out_pos,out_extend_right_pos,out_extend_down_pos])
+        self.add_wire(("metal3","via2","metal2"),[out_extend_right_pos,out_extend_down_pos,rail_pos])
+        self.add_via_center(("metal2","via2","metal3"),rail_pos)
+        
+        # Connect clk
+        clk_pin = self.msb_address_inst.get_pin("clk")
+        clk_pos = clk_pin.bc()
+        rail_pos = self.horz_control_bus_positions["clk_buf"]
+        bend_pos = vector(clk_pos.x,self.horz_control_bus_positions["clk_buf"].y)
+        self.add_path("metal1",[clk_pos,bend_pos,rail_pos])
+        
+
+            
+    def route(self):
+        """ Route all of the signals for the two bank SRAM. """
+
+        self.route_shared_banks()
+            
+        # connect the horizontal control bus to the vertical bus
+        # connect the data output to the data bus
+        for n in self.data_bus_names:
+            for i in [0,1]:
+                pin_pos = self.bank_inst[i].get_pin(n).uc()
+                rail_pos = vector(pin_pos.x,self.data_bus_positions[n].y)
+                self.add_path("metal2",[pin_pos,rail_pos])
+                self.add_via_center(("metal2","via2","metal3"),rail_pos)
+
+        self.route_single_msb_address()
+
+        # connect the banks to the vertical address bus
+        # connect the banks to the vertical control bus
+        for n in self.addr_bus_names + self.control_bus_names:
+            # Skip these from the horizontal bus
+            if n in ["vdd", "gnd"]: continue
+            # This will be the bank select, so skip it
+            if n == self.msb_bank_sel_addr: continue
+            pin0_pos = self.bank_inst[0].get_pin(n).rc()
+            pin1_pos = self.bank_inst[1].get_pin(n).lc()
+            rail_pos = vector(self.vert_control_bus_positions[n].x,pin0_pos.y)
+            self.add_path("metal3",[pin0_pos,pin1_pos])
+            self.add_via_center(("metal2","via2","metal3"),rail_pos)
+
+
+        
diff --git a/compiler/sram_4bank.py b/compiler/sram_4bank.py
new file mode 100644
index 00000000..e0bf48e4
--- /dev/null
+++ b/compiler/sram_4bank.py
@@ -0,0 +1,314 @@
+import sys
+from tech import drc, spice
+import debug
+import design
+from math import log,sqrt,ceil
+import contact
+from bank import bank
+from dff_buf_array import dff_buf_array
+from dff_array import dff_array
+import datetime
+import getpass
+from vector import vector
+from globals import OPTS, print_time
+
+class sram_4bank(design.design):
+    """
+    Procedures specific to a four bank SRAM.
+    """
+    def __init__(self, name):
+        design.__init__(self, name)
+    
+    def compute_bank_offsets(self):
+        """ Compute the overall offsets for a four bank SRAM """
+
+        # The main difference is that the four bank SRAM has the data bus in the middle of the four banks
+        # as opposed to the top of the banks.
+        
+        # In 4 bank SRAM, the height is determined by the bank decoder and address flop
+        self.vertical_bus_height = 2*self.bank.height + 4*self.bank_to_bus_distance + self.data_bus_height \
+                                   + self.supply_bus_height + self.msb_decoder.height + self.msb_address.width 
+        # The address bus extends down through the power rails, but control and bank_sel bus don't
+        self.addr_bus_height = self.vertical_bus_height
+
+        self.vertical_bus_offset = vector(self.bank.width + self.bank_to_bus_distance, 0)
+        self.data_bus_offset = vector(0, self.bank.height + self.bank_to_bus_distance)
+        self.supply_bus_offset = vector(0, self.data_bus_offset.y + self.data_bus_height \
+                                        + self.bank.height + 2*self.bank_to_bus_distance)        
+        self.control_bus_offset = vector(0, self.supply_bus_offset.y + self.supply_bus_height)
+        self.bank_sel_bus_offset = self.vertical_bus_offset + vector(self.m2_pitch*self.control_size,0)
+        self.addr_bus_offset = self.bank_sel_bus_offset.scale(1,0) + vector(self.m2_pitch*self.num_banks,0)
+
+        # Control is placed at the top above the control bus and everything
+        self.control_logic_position = vector(0, self.control_bus_offset.y + self.control_bus_height + self.m1_pitch)
+
+        # Bank select flops get put to the right of control logic above bank1 and the buses
+        # Leave a pitch to get the vdd rails up to M2
+        self.msb_address_position = vector(self.bank_inst[1].lx() + 3*self.supply_rail_pitch,
+                                           self.supply_bus_offset.y + self.supply_bus_height \
+                                           + 2*self.m1_pitch + self.msb_address.width)
+
+        # Decoder goes above the MSB address flops, and is flipped in Y
+        # separate the two by a bank to bus distance for nwell rules, just in case
+        self.msb_decoder_position = self.msb_address_position + vector(self.msb_decoder.width, self.bank_to_bus_distance)
+
+    
+    def add_modules(self):
+        """ Adds the modules and the buses to the top level """
+
+        self.compute_bus_sizes()
+
+        self.add_banks()
+
+        self.compute_bank_offsets()
+
+        self.add_busses()
+
+        self.add_logic()
+        
+        self.width = self.bank_inst[1].ur().x
+        self.height = max(self.control_logic_inst.uy(),self.msb_decoder_inst.uy())
+
+    def add_banks(self):
+        
+        # Placement of bank 0 (upper left)
+        bank_position_0 = vector(self.bank.width,
+                                 self.bank.height + self.data_bus_height + 2*self.bank_to_bus_distance)
+        self.bank_inst=[self.add_bank(0, bank_position_0, 1, -1)]
+
+        # Placement of bank 1 (upper right)
+        x_off = self.bank.width + self.vertical_bus_width + 2*self.bank_to_bus_distance
+        bank_position_1 = vector(x_off, bank_position_0.y)
+        self.bank_inst.append(self.add_bank(1, bank_position_1, 1, 1))
+
+        # Placement of bank 2 (bottom left)
+        y_off = self.bank.height
+        bank_position_2 = vector(bank_position_0.x, y_off)
+        self.bank_inst.append(self.add_bank(2, bank_position_2, -1, -1))
+
+        # Placement of bank 3 (bottom right)
+        bank_position_3 = vector(bank_position_1.x, bank_position_2.y)
+        self.bank_inst.append(self.add_bank(3, bank_position_3, -1, 1))
+        
+
+        
+    def add_logic(self):
+        """ Add the control and MSB decode/bank select logic for four banks """
+
+
+        self.add_control_logic(position=self.control_logic_position)
+
+        self.msb_address_inst = self.add_inst(name="msb_address",
+                                              mod=self.msb_address,
+                                              offset=self.msb_address_position,
+                                              rotate=270)
+
+        self.msb_bank_sel_addr = ["ADDR[{}]".format(i) for i in range(self.addr_size-2,self.addr_size,1)]        
+        temp = list(self.msb_bank_sel_addr)
+        temp.extend(["msb{0}[{1}]".format(j,i) for i in range(2) for j in ["","_bar"]])
+        temp.extend(["clk_buf", "vdd", "gnd"])
+        self.connect_inst(temp)
+        
+        self.msb_decoder_inst = self.add_inst(name="msb_decoder",
+                                              mod=self.msb_decoder,
+                                              offset=self.msb_decoder_position,
+                                              mirror="MY")
+        temp = ["msb[{}]".format(i) for i in range(2)]
+        temp.extend(["bank_sel[{}]".format(i) for i in range(4)])
+        temp.extend(["vdd", "gnd"])
+        self.connect_inst(temp)
+        
+    def route_double_msb_address(self):
+        """ Route two MSB address bits and the bank decoder for 4-bank SRAM """
+
+        # connect the MSB flops to the address input bus
+        for i in [0,1]:
+            msb_pins = self.msb_address_inst.get_pins("din[{}]".format(i))
+            for msb_pin in msb_pins:
+                if msb_pin.layer == "metal3":
+                    msb_pin_pos = msb_pin.lc()
+                    break
+            rail_pos = vector(self.vert_control_bus_positions[self.msb_bank_sel_addr[i]].x,msb_pin_pos.y)
+            self.add_path("metal3",[msb_pin_pos,rail_pos])
+            self.add_via_center(("metal2","via2","metal3"),rail_pos)
+        
+        # Connect clk
+        clk_pin = self.msb_address_inst.get_pin("clk")
+        clk_pos = clk_pin.bc()
+        rail_pos = self.horz_control_bus_positions["clk_buf"]
+        bend_pos = vector(clk_pos.x,self.horz_control_bus_positions["clk_buf"].y)
+        self.add_path("metal1",[clk_pos,bend_pos,rail_pos])
+
+        # Connect bank decoder outputs to the bank select vertical bus wires
+        for i in range(self.num_banks):
+            msb_pin = self.msb_decoder_inst.get_pin("out[{}]".format(i))
+            msb_pin_pos = msb_pin.lc()
+            rail_pos = vector(self.vert_control_bus_positions["bank_sel[{}]".format(i)].x,msb_pin_pos.y)
+            self.add_path("metal1",[msb_pin_pos,rail_pos])
+            self.add_via_center(("metal1","via1","metal2"),rail_pos)
+
+        # connect MSB flop outputs to the bank decoder inputs
+        msb_pin = self.msb_address_inst.get_pin("dout[0]")
+        msb_pin_pos = msb_pin.rc()
+        in_pin = self.msb_decoder_inst.get_pin("in[0]")
+        in_pos = in_pin.bc() + vector(0,1*self.m2_pitch,) # pin is up from bottom
+        out_pos = msb_pin_pos + vector(1*self.m2_pitch,0) # route out to the right
+        up_pos = vector(out_pos.x,in_pos.y) # and route up to the decoer
+        self.add_wire(("metal1","via1","metal2"),[msb_pin_pos,out_pos,up_pos,in_pos])
+        self.add_via_center(("metal1","via1","metal2"),in_pos)
+        self.add_via_center(("metal1","via1","metal2"),msb_pin_pos,rotate=90)
+            
+        msb_pin = self.msb_address_inst.get_pin("dout[1]")
+        msb_pin_pos = msb_pin.rc()
+        in_pin = self.msb_decoder_inst.get_pin("in[1]")
+        in_pos = in_pin.bc() + vector(0,self.bitcell.height+self.m2_pitch) # route the next row up
+        out_pos = msb_pin_pos + vector(2*self.m2_pitch,0) # route out to the right
+        up_pos = vector(out_pos.x,in_pos.y) # and route up to the decoer
+        self.add_wire(("metal1","via1","metal2"),[msb_pin_pos,out_pos,up_pos,in_pos])
+        self.add_via_center(("metal1","via1","metal2"),in_pos)
+        self.add_via_center(("metal1","via1","metal2"),msb_pin_pos,rotate=90)
+
+        self.route_double_msb_address_supplies()
+        
+    def route_double_msb_address_supplies(self):
+        """ Route the vdd/gnd bits of the 2-bit bank decoder. """
+        
+        # Route the right-most vdd/gnd of the right upper bank to the top of the decoder
+        vdd_pins = self.bank_inst[1].get_pins("vdd")
+        left_bank_vdd_pin = None
+        right_bank_vdd_pin = None
+        for vdd_pin in vdd_pins:
+            if vdd_pin.layer != "metal2":
+                continue
+            if left_bank_vdd_pin == None or vdd_pin.lx()<left_bank_vdd_pin.lx():
+                left_bank_vdd_pin = vdd_pin
+            if right_bank_vdd_pin == None or vdd_pin.lx()>right_bank_vdd_pin.lx():
+                right_bank_vdd_pin = vdd_pin
+            # Route to top
+            self.add_rect(layer="metal2",
+                          offset=vdd_pin.ul(),
+                          height=self.height-vdd_pin.uy(),
+                          width=vdd_pin.width())
+
+        gnd_pins = self.bank_inst[1].get_pins("gnd")
+        left_bank_gnd_pin = None
+        right_bank_gnd_pin = None
+        for gnd_pin in gnd_pins:
+            if gnd_pin.layer != "metal2":
+                continue
+            if left_bank_gnd_pin == None or gnd_pin.lx()<left_bank_gnd_pin.lx():
+                left_bank_gnd_pin = gnd_pin
+            if right_bank_gnd_pin == None or gnd_pin.lx()>right_bank_gnd_pin.lx():
+                right_bank_gnd_pin = gnd_pin
+            # Route to top
+            self.add_rect(layer="metal2",
+                          offset=gnd_pin.ul(),
+                          height=self.height-gnd_pin.uy(),
+                          width=gnd_pin.width())
+        
+        # Connect bank decoder vdd/gnd supplies using the previous bank pins
+        vdd_pins = self.msb_decoder_inst.get_pins("vdd")
+        for vdd_pin in vdd_pins:
+            if vdd_pin.layer != "metal1":
+                continue
+            rail1_pos = vector(left_bank_vdd_pin.cx(),vdd_pin.cy())
+            rail2_pos = vector(right_bank_vdd_pin.cx(),vdd_pin.cy())
+            self.add_path("metal1",[rail1_pos,rail2_pos])
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=rail1_pos,
+                                rotate=90,
+                                size=[1,3])
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=rail2_pos,
+                                rotate=90,
+                                size=[1,3])
+        gnd_pins = self.msb_decoder_inst.get_pins("gnd")
+        for gnd_pin in gnd_pins:
+            if gnd_pin.layer != "metal1":
+                continue
+            rail1_pos = vector(left_bank_gnd_pin.cx(),gnd_pin.cy())
+            rail2_pos = vector(right_bank_gnd_pin.cx(),gnd_pin.cy())
+            self.add_path("metal1",[rail1_pos,rail2_pos])
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=rail1_pos,
+                                rotate=90,
+                                size=[1,3])
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=rail2_pos,
+                                rotate=90,
+                                size=[1,3])
+        
+        # connect the bank MSB flop supplies
+        vdd_pins = self.msb_address_inst.get_pins("vdd")
+        # vdd pins go down to the rail
+        for vdd_pin in vdd_pins:
+            if vdd_pin.layer != "metal1":
+                continue
+            vdd_pos = vdd_pin.bc()
+            down_pos = vdd_pos - vector(0,self.m1_pitch)
+            rail_pos = vector(vdd_pos.x,self.horz_control_bus_positions["vdd"].y)
+            self.add_path("metal1",[vdd_pos,down_pos])            
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=down_pos,
+                                rotate=90)   
+            self.add_path("metal2",[down_pos,rail_pos])
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=rail_pos)        
+        # gnd pins go right to the rail
+        gnd_pins = self.msb_address_inst.get_pins("gnd")
+        for gnd_pin in gnd_pins:
+            if gnd_pin.layer != "metal2":
+                continue
+            rail1_pos = vector(left_bank_gnd_pin.cx(),gnd_pin.cy())
+            self.add_path("metal1",[rail1_pos,gnd_pin.lc()])
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                                offset=gnd_pin.lc(),
+                                rotate=90)
+            self.add_via_center(layers=("metal1","via1","metal2"),
+                         offset=rail1_pos,
+                         rotate=90,
+                         size=[1,3])            
+        
+        
+    def route(self):
+        """ Route all of the signals for the four bank SRAM. """
+        
+        self.route_shared_banks()
+
+        # connect the data output to the data bus
+        for n in self.data_bus_names:
+            for i in [0,1]:
+                pin_pos = self.bank_inst[i].get_pin(n).bc()
+                rail_pos = vector(pin_pos.x,self.data_bus_positions[n].y)
+                self.add_path("metal2",[pin_pos,rail_pos])
+                self.add_via_center(("metal2","via2","metal3"),rail_pos)
+
+            for i in [2,3]:
+                pin_pos = self.bank_inst[i].get_pin(n).uc()
+                rail_pos = vector(pin_pos.x,self.data_bus_positions[n].y)
+                self.add_path("metal2",[pin_pos,rail_pos])
+                self.add_via_center(("metal2","via2","metal3"),rail_pos)
+                
+        # route msb address bits
+        # route 2:4 decoder
+        self.route_double_msb_address()
+
+        # connect the banks to the vertical address bus
+        # connect the banks to the vertical control bus
+        for n in self.addr_bus_names + self.control_bus_names:
+            # Skip these from the horizontal bus
+            if n in ["vdd", "gnd"]: continue
+            # This will be the bank select, so skip it
+            if n in self.msb_bank_sel_addr: continue
+
+            for bank_id in [0,2]:
+                pin0_pos = self.bank_inst[bank_id].get_pin(n).rc()
+                pin1_pos = self.bank_inst[bank_id+1].get_pin(n).lc()
+                rail_pos = vector(self.vert_control_bus_positions[n].x,pin0_pos.y)
+                self.add_path("metal3",[pin0_pos,pin1_pos])
+                self.add_via_center(("metal2","via2","metal3"),rail_pos)
+            
+
+        self.route_bank_supply_rails(left_banks=[0,2], bottom_banks=[2,3])
+
+
diff --git a/compiler/tests/01_library_drc_test.py b/compiler/tests/01_library_drc_test.py
index e1f9506a..b809c14d 100755
--- a/compiler/tests/01_library_drc_test.py
+++ b/compiler/tests/01_library_drc_test.py
@@ -13,7 +13,6 @@ class library_drc_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        global verify
         import verify
 
         (gds_dir, gds_files) = setup_files()
@@ -31,11 +30,12 @@ class library_drc_test(openram_test):
         self.assertEqual(drc_errors, 0)
         globals.end_openram()
 
+
 def setup_files():
     gds_dir = OPTS.openram_tech + "/gds_lib"
     files = os.listdir(gds_dir)
     nametest = re.compile("\.gds$", re.IGNORECASE)
-    gds_files = filter(nametest.search, files)
+    gds_files = list(filter(nametest.search, files))
     return (gds_dir, gds_files)
 
 
@@ -45,3 +45,4 @@ if __name__ == "__main__":
     del sys.argv[1:]
     header(__file__, OPTS.tech_name)
     unittest.main()
+
diff --git a/compiler/tests/02_library_lvs_test.py b/compiler/tests/02_library_lvs_test.py
index 22f2d3d7..0b35f159 100755
--- a/compiler/tests/02_library_lvs_test.py
+++ b/compiler/tests/02_library_lvs_test.py
@@ -14,6 +14,7 @@ class library_lvs_test(openram_test):
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         import verify
+
         (gds_dir, sp_dir, allnames) = setup_files()
         lvs_errors = 0
         debug.info(1, "Performing LVS on: " + ", ".join(allnames))
@@ -28,7 +29,7 @@ class library_lvs_test(openram_test):
                 lvs_errors += 1
                 debug.error("Missing SPICE file {}".format(gds_name))
             lvs_errors += verify.run_lvs(f, gds_name, sp_name)
-            self.assertEqual(lvs_errors, 0)
+
         # fail if the error count is not zero
         self.assertEqual(lvs_errors, 0)
         globals.end_openram()
diff --git a/compiler/tests/03_contact_test.py b/compiler/tests/03_contact_test.py
index cf1d5f8c..b5938cec 100755
--- a/compiler/tests/03_contact_test.py
+++ b/compiler/tests/03_contact_test.py
@@ -15,7 +15,6 @@ class contact_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import contact
 
@@ -43,7 +42,6 @@ class contact_test(openram_test):
             c = contact.contact(layer_stack, (3, 3))
             self.local_drc_check(c)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/03_path_test.py b/compiler/tests/03_path_test.py
index 7f8af2d9..88a195c4 100755
--- a/compiler/tests/03_path_test.py
+++ b/compiler/tests/03_path_test.py
@@ -15,8 +15,7 @@ class path_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
-
+        
         import path
         import tech
         import design
@@ -84,8 +83,6 @@ class path_test(openram_test):
         path.path(w, layer_stack, position_list)
         self.local_drc_check(w)
 
-        # return it back to it's normal state
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/03_ptx_1finger_nmos_test.py b/compiler/tests/03_ptx_1finger_nmos_test.py
index af87aa1f..02ef0f2b 100755
--- a/compiler/tests/03_ptx_1finger_nmos_test.py
+++ b/compiler/tests/03_ptx_1finger_nmos_test.py
@@ -15,7 +15,6 @@ class ptx_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import ptx
         import tech
@@ -26,7 +25,6 @@ class ptx_test(openram_test):
                       tx_type="nmos")
         self.local_drc_check(fet)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 
diff --git a/compiler/tests/03_ptx_1finger_pmos_test.py b/compiler/tests/03_ptx_1finger_pmos_test.py
index 6b13b5c4..c00ccb72 100755
--- a/compiler/tests/03_ptx_1finger_pmos_test.py
+++ b/compiler/tests/03_ptx_1finger_pmos_test.py
@@ -15,7 +15,6 @@ class ptx_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import ptx
         import tech
@@ -26,7 +25,6 @@ class ptx_test(openram_test):
                       tx_type="pmos")
         self.local_drc_check(fet)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 
diff --git a/compiler/tests/03_ptx_3finger_nmos_test.py b/compiler/tests/03_ptx_3finger_nmos_test.py
index 1a68bbcf..60293266 100755
--- a/compiler/tests/03_ptx_3finger_nmos_test.py
+++ b/compiler/tests/03_ptx_3finger_nmos_test.py
@@ -15,7 +15,6 @@ class ptx_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import ptx
         import tech
@@ -28,7 +27,6 @@ class ptx_test(openram_test):
                       connect_poly=True)
         self.local_drc_check(fet)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 
diff --git a/compiler/tests/03_ptx_3finger_pmos_test.py b/compiler/tests/03_ptx_3finger_pmos_test.py
index e3570f1a..792de25f 100755
--- a/compiler/tests/03_ptx_3finger_pmos_test.py
+++ b/compiler/tests/03_ptx_3finger_pmos_test.py
@@ -15,7 +15,6 @@ class ptx_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import ptx
         import tech
@@ -28,7 +27,6 @@ class ptx_test(openram_test):
                       connect_poly=True)
         self.local_drc_check(fet)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/03_ptx_4finger_nmos_test.py b/compiler/tests/03_ptx_4finger_nmos_test.py
index 45722501..d4cc0da5 100755
--- a/compiler/tests/03_ptx_4finger_nmos_test.py
+++ b/compiler/tests/03_ptx_4finger_nmos_test.py
@@ -15,7 +15,6 @@ class ptx_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import ptx
         import tech
@@ -28,7 +27,6 @@ class ptx_test(openram_test):
                       connect_poly=True)
         self.local_drc_check(fet)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 
diff --git a/compiler/tests/03_ptx_4finger_pmos_test.py b/compiler/tests/03_ptx_4finger_pmos_test.py
index fb7dfd6c..c35390c9 100755
--- a/compiler/tests/03_ptx_4finger_pmos_test.py
+++ b/compiler/tests/03_ptx_4finger_pmos_test.py
@@ -15,7 +15,6 @@ class ptx_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import ptx
         import tech
@@ -28,7 +27,6 @@ class ptx_test(openram_test):
                       connect_poly=True)
         self.local_drc_check(fet)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/03_wire_test.py b/compiler/tests/03_wire_test.py
index 17abe160..cf50dc10 100755
--- a/compiler/tests/03_wire_test.py
+++ b/compiler/tests/03_wire_test.py
@@ -15,7 +15,6 @@ class wire_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import wire
         import tech
@@ -122,8 +121,6 @@ class wire_test(openram_test):
         wire.wire(w, layer_stack, position_list)
         self.local_drc_check(w)
 
-        # return it back to it's normal state
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/04_pbitcell_test.py b/compiler/tests/04_pbitcell_test.py
index 8a684839..b2eb7fb5 100755
--- a/compiler/tests/04_pbitcell_test.py
+++ b/compiler/tests/04_pbitcell_test.py
@@ -22,7 +22,6 @@ class pbitcell_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pbitcell
         import tech
@@ -67,9 +66,8 @@ class pbitcell_test(openram_test):
         tx = pbitcell.pbitcell(num_readwrite=2,num_write=0,num_read=0)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
-        OPTS.bitcell = "bitcell"
+
 
 
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/04_pinv_10x_test.py b/compiler/tests/04_pinv_10x_test.py
index 4e396b83..09eef9c3 100755
--- a/compiler/tests/04_pinv_10x_test.py
+++ b/compiler/tests/04_pinv_10x_test.py
@@ -17,7 +17,6 @@ class pinv_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pinv
         import tech
@@ -26,7 +25,6 @@ class pinv_test(openram_test):
         tx = pinv.pinv(size=8)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()        
 
 
diff --git a/compiler/tests/04_pinv_1x_beta_test.py b/compiler/tests/04_pinv_1x_beta_test.py
index d8c98ea6..17829e14 100755
--- a/compiler/tests/04_pinv_1x_beta_test.py
+++ b/compiler/tests/04_pinv_1x_beta_test.py
@@ -17,7 +17,6 @@ class pinv_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pinv
         import tech
@@ -26,7 +25,6 @@ class pinv_test(openram_test):
         tx = pinv.pinv(size=1, beta=3)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()        
 
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/04_pinv_1x_test.py b/compiler/tests/04_pinv_1x_test.py
index fa36a280..a0db1100 100755
--- a/compiler/tests/04_pinv_1x_test.py
+++ b/compiler/tests/04_pinv_1x_test.py
@@ -16,7 +16,6 @@ class pinv_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
         
 
         import pinv
@@ -26,7 +25,6 @@ class pinv_test(openram_test):
         tx = pinv.pinv(size=1)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()        
 
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/04_pinv_2x_test.py b/compiler/tests/04_pinv_2x_test.py
index bedb259f..66ea15da 100755
--- a/compiler/tests/04_pinv_2x_test.py
+++ b/compiler/tests/04_pinv_2x_test.py
@@ -17,7 +17,6 @@ class pinv_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pinv
         import tech
@@ -26,7 +25,6 @@ class pinv_test(openram_test):
         tx = pinv.pinv(size=2)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()        
 
 
diff --git a/compiler/tests/04_pinvbuf_test.py b/compiler/tests/04_pinvbuf_test.py
index 3fc5e3c3..ffe6fa33 100755
--- a/compiler/tests/04_pinvbuf_test.py
+++ b/compiler/tests/04_pinvbuf_test.py
@@ -17,7 +17,6 @@ class pinvbuf_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pinvbuf
 
@@ -25,7 +24,6 @@ class pinvbuf_test(openram_test):
         a = pinvbuf.pinvbuf(4,8)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/04_pnand2_test.py b/compiler/tests/04_pnand2_test.py
index adf3a4e8..af35bae8 100755
--- a/compiler/tests/04_pnand2_test.py
+++ b/compiler/tests/04_pnand2_test.py
@@ -19,7 +19,6 @@ class pnand2_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pnand2
         import tech
@@ -28,7 +27,6 @@ class pnand2_test(openram_test):
         tx = pnand2.pnand2(size=1)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/04_pnand3_test.py b/compiler/tests/04_pnand3_test.py
index 594be7ff..6984a0e0 100755
--- a/compiler/tests/04_pnand3_test.py
+++ b/compiler/tests/04_pnand3_test.py
@@ -19,7 +19,6 @@ class pnand3_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pnand3
         import tech
@@ -28,7 +27,6 @@ class pnand3_test(openram_test):
         tx = pnand3.pnand3(size=1)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/04_pnor2_test.py b/compiler/tests/04_pnor2_test.py
index fe18bd4c..a15f6907 100755
--- a/compiler/tests/04_pnor2_test.py
+++ b/compiler/tests/04_pnor2_test.py
@@ -19,7 +19,6 @@ class pnor2_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import pnor2
         import tech
@@ -28,7 +27,6 @@ class pnor2_test(openram_test):
         tx = pnor2.pnor2(size=1)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/04_precharge_test.py b/compiler/tests/04_precharge_test.py
index 018f6ef7..55460289 100755
--- a/compiler/tests/04_precharge_test.py
+++ b/compiler/tests/04_precharge_test.py
@@ -17,7 +17,6 @@ class precharge_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import precharge
         import tech
@@ -26,7 +25,6 @@ class precharge_test(openram_test):
         tx = precharge.precharge(name="precharge_driver", size=1)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/04_single_level_column_mux_test.py b/compiler/tests/04_single_level_column_mux_test.py
index 494fcd84..d282a11a 100755
--- a/compiler/tests/04_single_level_column_mux_test.py
+++ b/compiler/tests/04_single_level_column_mux_test.py
@@ -19,7 +19,6 @@ class single_level_column_mux_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import single_level_column_mux
         import tech
@@ -28,7 +27,6 @@ class single_level_column_mux_test(openram_test):
         tx = single_level_column_mux.single_level_column_mux(tx_size=8)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/05_bitcell_array_test.py b/compiler/tests/05_bitcell_array_test.py
index 849e6666..37649ad5 100755
--- a/compiler/tests/05_bitcell_array_test.py
+++ b/compiler/tests/05_bitcell_array_test.py
@@ -19,7 +19,6 @@ class array_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import bitcell_array
 
@@ -27,7 +26,6 @@ class array_test(openram_test):
         a = bitcell_array.bitcell_array(name="bitcell_array", cols=4, rows=4)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/05_pbitcell_array_test.py b/compiler/tests/05_pbitcell_array_test.py
index c4ad0b32..081c4d51 100644
--- a/compiler/tests/05_pbitcell_array_test.py
+++ b/compiler/tests/05_pbitcell_array_test.py
@@ -11,27 +11,26 @@ import globals
 from globals import OPTS
 import debug
 
-#@unittest.skip("SKIPPING 05_array_multiport_test")
-
-class array_multiport_test(openram_test):
+#@unittest.skip("SKIPPING 05_pbitcell_array_test")
+class pbitcell_array_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import bitcell_array
 
+        debug.info(2, "Testing 4x4 array for multiport bitcell, with read ports at the edge of the bit cell")
         OPTS.bitcell = "pbitcell"
         OPTS.rw_ports = 2
         OPTS.r_ports = 2
         OPTS.w_ports = 2
-        
-        debug.info(2, "Testing 4x4 array for multiport bitcell, with read ports at the edge of the bit cell")
         a = bitcell_array.bitcell_array(name="pbitcell_array", cols=4, rows=4)
         self.local_check(a)
-        
+            
+        debug.info(2, "Testing 4x4 array for multiport bitcell, with read/write ports at the edge of the bit cell")
+        OPTS.bitcell = "pbitcell"
         OPTS.rw_ports = 2
         OPTS.r_ports = 0
         OPTS.w_ports = 2
@@ -47,10 +46,12 @@ class array_multiport_test(openram_test):
         debug.info(2, "Testing 4x4 array for multiport bitcell, with read/write ports at the edge of the bit cell")
         a = bitcell_array.bitcell_array(name="pbitcell_array", cols=4, rows=4)
         self.local_check(a)
+        a = bitcell_array.bitcell_array(name="pbitcell_array", cols=4, rows=4)
+        self.local_check(a)
 
-        OPTS.bitcell = "bitcell"
         OPTS.check_lvsdrc = True
         globals.end_openram()
+        OPTS.bitcell = "bitcell"
 
 # instantiate a copy of the class to actually run the test
 if __name__ == "__main__":
diff --git a/compiler/tests/06_hierarchical_decoder_test.py b/compiler/tests/06_hierarchical_decoder_test.py
index 48cae531..eb0b105a 100755
--- a/compiler/tests/06_hierarchical_decoder_test.py
+++ b/compiler/tests/06_hierarchical_decoder_test.py
@@ -17,7 +17,6 @@ class hierarchical_decoder_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import hierarchical_decoder
         import tech
@@ -48,7 +47,6 @@ class hierarchical_decoder_test(openram_test):
         a = hierarchical_decoder.hierarchical_decoder(rows=512)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/06_hierarchical_predecode2x4_test.py b/compiler/tests/06_hierarchical_predecode2x4_test.py
index 021f53b6..79db3665 100755
--- a/compiler/tests/06_hierarchical_predecode2x4_test.py
+++ b/compiler/tests/06_hierarchical_predecode2x4_test.py
@@ -17,7 +17,6 @@ class hierarchical_predecode2x4_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import hierarchical_predecode2x4 as pre
         import tech
@@ -26,7 +25,6 @@ class hierarchical_predecode2x4_test(openram_test):
         a = pre.hierarchical_predecode2x4()
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/06_hierarchical_predecode3x8_test.py b/compiler/tests/06_hierarchical_predecode3x8_test.py
index e6bcda2d..b6609829 100755
--- a/compiler/tests/06_hierarchical_predecode3x8_test.py
+++ b/compiler/tests/06_hierarchical_predecode3x8_test.py
@@ -17,7 +17,6 @@ class hierarchical_predecode3x8_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import hierarchical_predecode3x8 as pre
         import tech
@@ -26,7 +25,6 @@ class hierarchical_predecode3x8_test(openram_test):
         a = pre.hierarchical_predecode3x8()
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/07_single_level_column_mux_array_test.py b/compiler/tests/07_single_level_column_mux_array_test.py
index 120f1093..1becd179 100755
--- a/compiler/tests/07_single_level_column_mux_array_test.py
+++ b/compiler/tests/07_single_level_column_mux_array_test.py
@@ -16,7 +16,6 @@ class single_level_column_mux_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import single_level_column_mux_array
         
@@ -32,7 +31,6 @@ class single_level_column_mux_test(openram_test):
         a = single_level_column_mux_array.single_level_column_mux_array(columns=32, word_size=4)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True        
         globals.end_openram()
         
 
diff --git a/compiler/tests/08_precharge_array_test.py b/compiler/tests/08_precharge_array_test.py
index 84eaf6ea..d4a3190f 100755
--- a/compiler/tests/08_precharge_array_test.py
+++ b/compiler/tests/08_precharge_array_test.py
@@ -17,7 +17,6 @@ class precharge_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import precharge_array
         import tech
@@ -26,7 +25,6 @@ class precharge_test(openram_test):
         pc = precharge_array.precharge_array(columns=3)
         self.local_check(pc)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 
diff --git a/compiler/tests/08_wordline_driver_test.py b/compiler/tests/08_wordline_driver_test.py
index 1688bb5b..af97f018 100755
--- a/compiler/tests/08_wordline_driver_test.py
+++ b/compiler/tests/08_wordline_driver_test.py
@@ -19,7 +19,6 @@ class wordline_driver_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import wordline_driver
         import tech
@@ -28,7 +27,6 @@ class wordline_driver_test(openram_test):
         tx = wordline_driver.wordline_driver(rows=8)
         self.local_check(tx)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/09_sense_amp_array_test.py b/compiler/tests/09_sense_amp_array_test.py
index db1adf75..ba483218 100755
--- a/compiler/tests/09_sense_amp_array_test.py
+++ b/compiler/tests/09_sense_amp_array_test.py
@@ -17,7 +17,6 @@ class sense_amp_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import sense_amp_array
 
@@ -30,7 +29,6 @@ class sense_amp_test(openram_test):
         a = sense_amp_array.sense_amp_array(word_size=4, words_per_row=4)
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/10_write_driver_array_test.py b/compiler/tests/10_write_driver_array_test.py
index bc47d3ab..d7f1f7ec 100755
--- a/compiler/tests/10_write_driver_array_test.py
+++ b/compiler/tests/10_write_driver_array_test.py
@@ -17,7 +17,6 @@ class write_driver_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import write_driver_array
 
@@ -29,7 +28,6 @@ class write_driver_test(openram_test):
         a = write_driver_array.write_driver_array(columns=16, word_size=8)
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/11_dff_array_test.py b/compiler/tests/11_dff_array_test.py
index a194ddad..e85056e9 100755
--- a/compiler/tests/11_dff_array_test.py
+++ b/compiler/tests/11_dff_array_test.py
@@ -17,7 +17,6 @@ class dff_array_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import dff_array
 
@@ -33,7 +32,6 @@ class dff_array_test(openram_test):
         a = dff_array.dff_array(rows=3, columns=1)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/11_dff_buf_array_test.py b/compiler/tests/11_dff_buf_array_test.py
index dc1af1e7..6c40e447 100755
--- a/compiler/tests/11_dff_buf_array_test.py
+++ b/compiler/tests/11_dff_buf_array_test.py
@@ -17,7 +17,6 @@ class dff_buf_array_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import dff_buf_array
 
@@ -33,7 +32,6 @@ class dff_buf_array_test(openram_test):
         a = dff_buf_array.dff_buf_array(rows=3, columns=1)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/11_dff_buf_test.py b/compiler/tests/11_dff_buf_test.py
index 22d0e3cb..44aca54c 100755
--- a/compiler/tests/11_dff_buf_test.py
+++ b/compiler/tests/11_dff_buf_test.py
@@ -17,7 +17,6 @@ class dff_buf_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import dff_buf
 
@@ -25,7 +24,6 @@ class dff_buf_test(openram_test):
         a = dff_buf.dff_buf(4, 8)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/11_dff_inv_array_test.py b/compiler/tests/11_dff_inv_array_test.py
index 4781d199..3d2b8cac 100755
--- a/compiler/tests/11_dff_inv_array_test.py
+++ b/compiler/tests/11_dff_inv_array_test.py
@@ -17,7 +17,6 @@ class dff_inv_array_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import dff_inv_array
 
@@ -33,7 +32,6 @@ class dff_inv_array_test(openram_test):
         a = dff_inv_array.dff_inv_array(rows=3, columns=1)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/11_dff_inv_test.py b/compiler/tests/11_dff_inv_test.py
index a20f2df5..b09a6591 100755
--- a/compiler/tests/11_dff_inv_test.py
+++ b/compiler/tests/11_dff_inv_test.py
@@ -17,7 +17,6 @@ class dff_inv_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import dff_inv
 
@@ -25,7 +24,6 @@ class dff_inv_test(openram_test):
         a = dff_inv.dff_inv(4)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/11_ms_flop_array_test.py b/compiler/tests/11_ms_flop_array_test.py
index 050afd71..97ef6ece 100755
--- a/compiler/tests/11_ms_flop_array_test.py
+++ b/compiler/tests/11_ms_flop_array_test.py
@@ -17,7 +17,6 @@ class dff_array_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import ms_flop_array
 
@@ -29,7 +28,6 @@ class dff_array_test(openram_test):
         a = ms_flop_array.ms_flop_array(columns=16, word_size=8)
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/12_tri_gate_array_test.py b/compiler/tests/12_tri_gate_array_test.py
index 9f61a5b6..08d1596d 100755
--- a/compiler/tests/12_tri_gate_array_test.py
+++ b/compiler/tests/12_tri_gate_array_test.py
@@ -17,7 +17,6 @@ class tri_gate_array_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import tri_gate_array
 
@@ -29,7 +28,6 @@ class tri_gate_array_test(openram_test):
         a = tri_gate_array.tri_gate_array(columns=16, word_size=8)
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/13_delay_chain_test.py b/compiler/tests/13_delay_chain_test.py
index ef2d1a85..d8a2d67c 100755
--- a/compiler/tests/13_delay_chain_test.py
+++ b/compiler/tests/13_delay_chain_test.py
@@ -17,7 +17,6 @@ class delay_chain_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import delay_chain
 
@@ -25,7 +24,6 @@ class delay_chain_test(openram_test):
         a = delay_chain.delay_chain(fanout_list=[4, 4, 4, 4])
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/14_replica_bitline_test.py b/compiler/tests/14_replica_bitline_test.py
index 97598693..b393c136 100755
--- a/compiler/tests/14_replica_bitline_test.py
+++ b/compiler/tests/14_replica_bitline_test.py
@@ -17,7 +17,6 @@ class replica_bitline_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import replica_bitline
 
@@ -34,7 +33,6 @@ class replica_bitline_test(openram_test):
         a = replica_bitline.replica_bitline(stages,fanout,rows)
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/16_control_logic_test.py b/compiler/tests/16_control_logic_test.py
index 231e2440..7aeb54c1 100755
--- a/compiler/tests/16_control_logic_test.py
+++ b/compiler/tests/16_control_logic_test.py
@@ -17,7 +17,6 @@ class control_logic_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import control_logic
         import tech
@@ -26,7 +25,6 @@ class control_logic_test(openram_test):
         a = control_logic.control_logic(num_rows=128)
         self.local_check(a)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/19_bank_select_test.py b/compiler/tests/19_bank_select_test.py
index 025e4cc4..955c7b4e 100755
--- a/compiler/tests/19_bank_select_test.py
+++ b/compiler/tests/19_bank_select_test.py
@@ -17,7 +17,6 @@ class bank_select_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import bank_select
 
@@ -25,7 +24,6 @@ class bank_select_test(openram_test):
         a = bank_select.bank_select()
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/19_multi_bank_test.py b/compiler/tests/19_multi_bank_test.py
index 088b810b..1a900f4c 100755
--- a/compiler/tests/19_multi_bank_test.py
+++ b/compiler/tests/19_multi_bank_test.py
@@ -17,7 +17,6 @@ class multi_bank_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import bank
 
@@ -37,7 +36,6 @@ class multi_bank_test(openram_test):
         a = bank.bank(word_size=2, num_words=128, words_per_row=8, num_banks=2, name="bank4_multi")
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/19_single_bank_test.py b/compiler/tests/19_single_bank_test.py
index 4b4ba7df..5bbc60ad 100755
--- a/compiler/tests/19_single_bank_test.py
+++ b/compiler/tests/19_single_bank_test.py
@@ -17,7 +17,6 @@ class single_bank_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import bank
 
@@ -38,7 +37,6 @@ class single_bank_test(openram_test):
         a = bank.bank(word_size=2, num_words=128, words_per_row=8, num_banks=1, name="bank4_single")
         self.local_check(a)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/20_sram_1bank_test.py b/compiler/tests/20_sram_1bank_test.py
index 8289191b..6bc738dd 100755
--- a/compiler/tests/20_sram_1bank_test.py
+++ b/compiler/tests/20_sram_1bank_test.py
@@ -17,7 +17,6 @@ class sram_1bank_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import sram
 
@@ -37,7 +36,6 @@ class sram_1bank_test(openram_test):
         # a = sram.sram(word_size=2, num_words=128, num_banks=1, name="sram4")
         # self.local_check(a, final_verification=True)
         
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/20_sram_2bank_test.py b/compiler/tests/20_sram_2bank_test.py
index 9334040a..7ae6bf13 100755
--- a/compiler/tests/20_sram_2bank_test.py
+++ b/compiler/tests/20_sram_2bank_test.py
@@ -18,7 +18,6 @@ class sram_2bank_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import sram
 
@@ -38,7 +37,6 @@ class sram_2bank_test(openram_test):
         # a = sram.sram(word_size=2, num_words=256 num_banks=2, name="sram4")
         # self.local_check(a, final_verification=True)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/20_sram_4bank_test.py b/compiler/tests/20_sram_4bank_test.py
index 2e8bfefc..3fb69dc9 100755
--- a/compiler/tests/20_sram_4bank_test.py
+++ b/compiler/tests/20_sram_4bank_test.py
@@ -18,7 +18,6 @@ class sram_4bank_test(openram_test):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
         global verify
         import verify
-        OPTS.check_lvsdrc = False
 
         import sram
 
@@ -38,7 +37,6 @@ class sram_4bank_test(openram_test):
         # a = sram.sram(word_size=2, num_words=256, num_banks=4, name="sram4")
         # self.local_check(a, final_verification=True)
 
-        OPTS.check_lvsdrc = True
         globals.end_openram()
         
 # instantiate a copy of the class to actually run the test
diff --git a/compiler/tests/21_hspice_delay_test.py b/compiler/tests/21_hspice_delay_test.py
index 9ac3db2e..289f3934 100755
--- a/compiler/tests/21_hspice_delay_test.py
+++ b/compiler/tests/21_hspice_delay_test.py
@@ -15,9 +15,9 @@ class timing_sram_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
         OPTS.spice_name="hspice"
         OPTS.analytical_delay = False
+
         
         # This is a hack to reload the characterizer __init__ with the spice version
         from importlib import reload
@@ -35,7 +35,6 @@ class timing_sram_test(openram_test):
                       num_banks=OPTS.num_banks,
                       name="sram1")
 
-        OPTS.check_lvsdrc = True
 
         tempspice = OPTS.openram_temp + "temp.sp"
         s.sp_write(tempspice)
@@ -85,12 +84,6 @@ class timing_sram_test(openram_test):
             else:
                 self.isclose(data[k],golden_data[k],0.15)
 
-                
-        # reset these options
-        OPTS.check_lvsdrc = True
-        OPTS.analytical_delay = True
-        reload(characterizer)
-
         globals.end_openram()
         
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/21_hspice_setuphold_test.py b/compiler/tests/21_hspice_setuphold_test.py
index 78403a56..f9d8a01c 100755
--- a/compiler/tests/21_hspice_setuphold_test.py
+++ b/compiler/tests/21_hspice_setuphold_test.py
@@ -15,7 +15,6 @@ class timing_setup_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
         OPTS.spice_name="hspice"
         OPTS.analytical_delay = False
 
@@ -27,7 +26,6 @@ class timing_setup_test(openram_test):
         if not OPTS.spice_exe:
             debug.error("Could not find {} simulator.".format(OPTS.spice_name),-1)
             
-
         import sram
         import tech
         slews = [tech.spice["rise_time"]*2]
@@ -59,9 +57,6 @@ class timing_setup_test(openram_test):
             else:
                 self.isclose(data[k],golden_data[k],0.15)
 
-        OPTS.check_lvsdrc = True
-        OPTS.analytical_delay = True
-        reload(characterizer)
         globals.end_openram()
         
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/21_ngspice_delay_test.py b/compiler/tests/21_ngspice_delay_test.py
index 7f7bfd39..739d63ea 100755
--- a/compiler/tests/21_ngspice_delay_test.py
+++ b/compiler/tests/21_ngspice_delay_test.py
@@ -15,7 +15,6 @@ class timing_sram_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
         OPTS.spice_name="ngspice"
         OPTS.analytical_delay = False
 
@@ -84,12 +83,6 @@ class timing_sram_test(openram_test):
             else:
                 self.isclose(data[k],golden_data[k],0.15)
 
-        # reset these options
-        OPTS.check_lvsdrc = True
-        OPTS.spice_name="hspice"
-        OPTS.analytical_delay = True
-        reload(characterizer)
-
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/21_ngspice_setuphold_test.py b/compiler/tests/21_ngspice_setuphold_test.py
index 9a8ff67c..24c69aa7 100755
--- a/compiler/tests/21_ngspice_setuphold_test.py
+++ b/compiler/tests/21_ngspice_setuphold_test.py
@@ -15,7 +15,6 @@ class timing_setup_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
         OPTS.spice_name="ngspice"
         OPTS.analytical_delay = False
 
@@ -58,12 +57,7 @@ class timing_setup_test(openram_test):
             else:
                 self.isclose(data[k],golden_data[k],0.15)
 
-        # reset these options
-        OPTS.check_lvsdrc = True
-        OPTS.spice_name="hspice"
-        OPTS.analytical_delay = True
         reload(characterizer)
-
         globals.end_openram()
 
 # instantiate a copdsay of the class to actually run the test
diff --git a/compiler/tests/22_pex_test.py b/compiler/tests/22_pex_test.py
old mode 100644
new mode 100755
index fbde5145..24cb7733
--- a/compiler/tests/22_pex_test.py
+++ b/compiler/tests/22_pex_test.py
@@ -11,11 +11,22 @@ import globals
 from globals import OPTS
 import debug
 
-@unittest.skip("SKIPPING 22_sram_func_test")
+@unittest.skip("SKIPPING 22_sram_pex_test")
 class sram_func_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
+
+        OPTS.use_pex = True
+
+        # This is a hack to reload the characterizer __init__ with the spice version
+        from importlib import reload
+        import characterizer
+        reload(characterizer)
+        from characterizer import setup_hold
+        if not OPTS.spice_exe:
+            debug.error("Could not find {} simulator.".format(OPTS.spice_name),-1)
+
         global verify
         import verify
 
@@ -31,14 +42,10 @@ class sram_func_test(openram_test):
         import tech
 
         debug.info(1, "Testing timing for sample 1bit, 16words SRAM with 1 bank")
-        OPTS.check_lvsdrc = False
-        OPTS.use_pex = True
         s = sram.sram(word_size=OPTS.word_size,
                       num_words=OPTS.num_words,
                       num_banks=OPTS.num_banks,
                       name="test_sram1")
-        OPTS.check_lvsdrc = True
-        OPTS.use_pex = False
 
         tempspice = OPTS.openram_temp + "temp.sp"
         tempgds = OPTS.openram_temp + "temp.gds"
@@ -90,7 +97,7 @@ class sram_func_test(openram_test):
         self.assertTrue(round(value1) > 0.5 * tech.spice["supply_voltage"])
         self.assertTrue(round(value2) < 0.5 * tech.spice["supply_voltage"])
 
-        OPTS.check_lvsdrc = True
+
 
     def convert_voltage_unit(self, string):
         newstring = ""
diff --git a/compiler/tests/22_sram_func_test.py b/compiler/tests/22_sram_func_test.py
index 63b8bdd2..22443c5a 100755
--- a/compiler/tests/22_sram_func_test.py
+++ b/compiler/tests/22_sram_func_test.py
@@ -11,12 +11,11 @@ import globals
 from globals import OPTS
 import debug
 
+@unittest.skip("SKIPPING 22_sram_func_test")
 class sram_func_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
-        OPTS.spice_name="" # Unset to use any simulator
         OPTS.analytical_delay = False
 
         # This is a hack to reload the characterizer __init__ with the spice version
@@ -35,8 +34,6 @@ class sram_func_test(openram_test):
                       num_banks=1,
                       name="sram_func_test")
 
-        OPTS.check_lvsdrc = True
-
         tempspice = OPTS.openram_temp + "temp.sp"
         s.sp_write(tempspice)
 
@@ -45,7 +42,7 @@ class sram_func_test(openram_test):
         debug.info(1, "Probe address {0} probe data {1}".format(probe_address, probe_data))
 
         corner = (OPTS.process_corners[0], OPTS.supply_voltages[0], OPTS.temperatures[0])
-        d = delay.delay(s,tempspice,corner)
+        d = delay(s,tempspice,corner)
         d.set_probe(probe_address,probe_data)
 
         # This will exit if it doesn't find a feasible period
@@ -55,7 +52,7 @@ class sram_func_test(openram_test):
         feasible_period = d.find_feasible_period()
 
         os.remove(tempspice)
-        OPTS.analytical_delay = True
+
         reload(characterizer)
         globals.end_openram()
         
diff --git a/compiler/tests/23_lib_sram_model_test.py b/compiler/tests/23_lib_sram_model_test.py
index 9eb8ac5b..2691de48 100755
--- a/compiler/tests/23_lib_sram_model_test.py
+++ b/compiler/tests/23_lib_sram_model_test.py
@@ -15,7 +15,6 @@ class lib_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
 
         import sram
         from characterizer import lib
@@ -25,8 +24,7 @@ class lib_test(openram_test):
                       num_words=16,
                       num_banks=1,
                       name="sram_2_16_1_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = True
-
+        
         tempspice = OPTS.openram_temp + "temp.sp"
         s.sp_write(tempspice)
 
diff --git a/compiler/tests/23_lib_sram_prune_test.py b/compiler/tests/23_lib_sram_prune_test.py
index 4227bc44..b2f45d8a 100755
--- a/compiler/tests/23_lib_sram_prune_test.py
+++ b/compiler/tests/23_lib_sram_prune_test.py
@@ -15,8 +15,6 @@ class lib_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
-        OPTS.spice_name="" # Unset to use any simulator
         OPTS.analytical_delay = False
         OPTS.trim_netlist = True
 
@@ -35,7 +33,6 @@ class lib_test(openram_test):
                       num_words=16,
                       num_banks=1,
                       name="sram_2_16_1_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = True
 
         tempspice = OPTS.openram_temp + "temp.sp"
         s.sp_write(tempspice)
@@ -54,7 +51,6 @@ class lib_test(openram_test):
             golden = "{0}/golden/{1}".format(os.path.dirname(os.path.realpath(__file__)),newname)
             self.isapproxdiff(libname,golden,0.40)
 
-        OPTS.analytical_delay = True
         reload(characterizer)
         globals.end_openram()
         
diff --git a/compiler/tests/23_lib_sram_test.py b/compiler/tests/23_lib_sram_test.py
index 46750250..80f34064 100755
--- a/compiler/tests/23_lib_sram_test.py
+++ b/compiler/tests/23_lib_sram_test.py
@@ -15,8 +15,6 @@ class lib_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = False
-        OPTS.spice_name="" # Unset to use any simulator
         OPTS.analytical_delay = False
         OPTS.trim_netlist = False
 
@@ -35,7 +33,6 @@ class lib_test(openram_test):
                       num_words=16,
                       num_banks=1,
                       name="sram_2_16_1_{0}".format(OPTS.tech_name))
-        OPTS.check_lvsdrc = True
 
         tempspice = OPTS.openram_temp + "temp.sp"
         s.sp_write(tempspice)
@@ -53,8 +50,6 @@ class lib_test(openram_test):
             golden = "{0}/golden/{1}".format(os.path.dirname(os.path.realpath(__file__)),filename)
             self.isapproxdiff(libname,golden,0.40)
 
-        OPTS.analytical_delay = True
-        OPTS.trim_netlist = True
         reload(characterizer)
         globals.end_openram()
         
diff --git a/compiler/tests/24_lef_sram_test.py b/compiler/tests/24_lef_sram_test.py
index 4cd654ae..fbd16034 100755
--- a/compiler/tests/24_lef_sram_test.py
+++ b/compiler/tests/24_lef_sram_test.py
@@ -15,8 +15,6 @@ class lef_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        # we will manually run lvs/drc
-        OPTS.check_lvsdrc = False
 
         import sram
 
@@ -26,8 +24,6 @@ class lef_test(openram_test):
                       num_banks=OPTS.num_banks,
                       name="sram_2_16_1_{0}".format(OPTS.tech_name))
 
-        OPTS.check_lvsdrc = True
-
         gdsfile = s.name + ".gds"
         leffile = s.name + ".lef"
         gdsname = OPTS.openram_temp + gdsfile
diff --git a/compiler/tests/25_verilog_sram_test.py b/compiler/tests/25_verilog_sram_test.py
index 8ceb093b..fe0be3d9 100755
--- a/compiler/tests/25_verilog_sram_test.py
+++ b/compiler/tests/25_verilog_sram_test.py
@@ -15,8 +15,6 @@ class verilog_test(openram_test):
 
     def runTest(self):
         globals.init_openram("config_20_{0}".format(OPTS.tech_name))
-        # we will manually run lvs/drc
-        OPTS.check_lvsdrc = False
 
         import sram
 
@@ -26,8 +24,6 @@ class verilog_test(openram_test):
                       num_banks=OPTS.num_banks,
                       name="sram_2_16_1_{0}".format(OPTS.tech_name))
 
-        OPTS.check_lvsdrc = True
-
         vfile = s.name + ".v"
         vname = OPTS.openram_temp + vfile
         s.verilog_write(vname)
diff --git a/compiler/tests/30_openram_test.py b/compiler/tests/30_openram_test.py
index 02fa4759..51546ae3 100755
--- a/compiler/tests/30_openram_test.py
+++ b/compiler/tests/30_openram_test.py
@@ -12,6 +12,7 @@ sys.path.append(os.path.join(sys.path[0],".."))
 import globals
 from globals import OPTS
 import debug
+import getpass
 
 class openram_test(openram_test):
 
@@ -72,10 +73,7 @@ class openram_test(openram_test):
             shutil.rmtree(out_path, ignore_errors=True)
         self.assertEqual(os.path.exists(out_path),False)
 
-        # The default was on, so disable it.
-        OPTS.check_lvsdrc=False
         globals.end_openram()
-        OPTS.check_lvsdrc=True        
 
 # instantiate a copy of the class to actually run the test
 if __name__ == "__main__":
diff --git a/compiler/tests/regress.py b/compiler/tests/regress.py
index daf9f3b6..d97def2b 100755
--- a/compiler/tests/regress.py
+++ b/compiler/tests/regress.py
@@ -27,5 +27,13 @@ modules = map(__import__, moduleNames)
 suite = unittest.TestSuite()
 load = unittest.defaultTestLoader.loadTestsFromModule
 suite.addTests(map(load, modules))
-ret = not unittest.TextTestRunner(verbosity=2).run(suite).wasSuccessful()
-sys.exit(ret)
+
+test_runner = unittest.TextTestRunner(verbosity=2,stream=sys.stderr)
+test_result = test_runner.run(suite)
+
+import verify
+verify.print_drc_stats()
+verify.print_lvs_stats()
+verify.print_pex_stats()        
+
+sys.exit(not test_result.wasSuccessful())
diff --git a/compiler/tests/testutils.py b/compiler/tests/testutils.py
index caef7211..7949e113 100644
--- a/compiler/tests/testutils.py
+++ b/compiler/tests/testutils.py
@@ -1,5 +1,5 @@
 import unittest,warnings
-import sys,os,glob
+import sys,os,glob,copy
 sys.path.append(os.path.join(sys.path[0],".."))
 from globals import OPTS
 import debug
@@ -8,17 +8,23 @@ class openram_test(unittest.TestCase):
     """ Base unit test that we have some shared classes in. """
     
     def local_drc_check(self, w):
+
+        self.reset()
+
         tempgds = OPTS.openram_temp + "temp.gds"
         w.gds_write(tempgds)
         import verify
-        self.assertFalse(verify.run_drc(w.name, tempgds))
 
-        files = glob.glob(OPTS.openram_temp + '*')
-        for f in files:
-            os.remove(f)        
+        result=verify.run_drc(w.name, tempgds)
+        if result != 0:
+            self.fail("DRC failed: {}".format(a.name))
+
+        self.cleanup()
     
     def local_check(self, a, final_verification=False):
 
+        self.reset()
+        
         tempspice = OPTS.openram_temp + "temp.sp"
         tempgds = OPTS.openram_temp + "temp.gds"
 
@@ -27,19 +33,12 @@ class openram_test(unittest.TestCase):
 
         import verify
         result=verify.run_drc(a.name, tempgds)
-        self.reset()
-        try:
-            self.assertTrue(result==0)
-        except:
+        if result != 0:
             self.fail("DRC failed: {}".format(a.name))
 
             
         result=verify.run_lvs(a.name, tempgds, tempspice, final_verification)
-        self.reset()
-        try:
-            self.assertTrue(result==0)
-        except:
-            self.reset()
+        if result != 0:
             self.fail("LVS mismatch: {}".format(a.name))
 
         if OPTS.purge_temp:
@@ -54,9 +53,14 @@ class openram_test(unittest.TestCase):
                 os.remove(f)        
 
     def reset(self):
-        """ Reset the static duplicate name checker for unit tests """
-        import design
-        design.design.name_map=[]
+        """ 
+        Reset everything after each test.
+        """
+        # Reset the static duplicate name checker for unit tests.
+        import hierarchy_design
+        hierarchy_design.hierarchy_design.name_map=[]
+        
+
 
     def isclose(self, value1,value2,error_tolerance=1e-2):
         """ This is used to compare relative values. """
diff --git a/compiler/verify/__init__.py b/compiler/verify/__init__.py
index a83629b0..2199e765 100644
--- a/compiler/verify/__init__.py
+++ b/compiler/verify/__init__.py
@@ -13,7 +13,7 @@ import debug
 from globals import OPTS,find_exe,get_tool
 import sys
 
-debug.info(2,"Initializing verify...")
+debug.info(1,"Initializing verify...")
 
 if not OPTS.check_lvsdrc:
     debug.info(1,"LVS/DRC/PEX disabled.")
@@ -21,6 +21,7 @@ if not OPTS.check_lvsdrc:
     OPTS.lvs_exe = None
     OPTS.pex_exe = None
 else:
+    debug.info(1, "Finding DRC/LVS/PEX tools.")    
     OPTS.drc_exe = get_tool("DRC",["calibre","assura","magic"])
     OPTS.lvs_exe = get_tool("LVS",["calibre","assura","netgen"])
     OPTS.pex_exe = get_tool("PEX",["calibre","magic"])
@@ -31,22 +32,22 @@ if OPTS.check_lvsdrc and OPTS.tech_name == "freepdk45":
 if OPTS.drc_exe == None:
     pass
 elif "calibre"==OPTS.drc_exe[0]:
-    from .calibre import run_drc
+    from .calibre import run_drc,print_drc_stats
 elif "assura"==OPTS.drc_exe[0]:
-    from .assura import run_drc
+    from .assura import run_drc,print_drc_stats
 elif "magic"==OPTS.drc_exe[0]:
-    from .magic import run_drc
+    from .magic import run_drc,print_drc_stats
 else:
     debug.warning("Did not find a supported DRC tool.")
 
 if OPTS.lvs_exe == None:
     pass
 elif "calibre"==OPTS.lvs_exe[0]:
-    from .calibre import run_lvs
+    from .calibre import run_lvs,print_lvs_stats
 elif "assura"==OPTS.lvs_exe[0]:
-    from .assura import run_lvs
+    from .assura import run_lvs,print_lvs_stats
 elif "netgen"==OPTS.lvs_exe[0]:
-    from .magic import run_lvs
+    from .magic import run_lvs,print_lvs_stats
 else:
     debug.warning("Did not find a supported LVS tool.")
 
@@ -54,9 +55,9 @@ else:
 if OPTS.pex_exe == None:
     pass
 elif "calibre"==OPTS.pex_exe[0]:
-    from .calibre import run_pex
+    from .calibre import run_pex,print_pex_stats
 elif "magic"==OPTS.pex_exe[0]:
-    from .magic import run_pex
+    from .magic import run_pex,print_pex_stats
 else:
     debug.warning("Did not find a supported PEX tool.")
     
diff --git a/compiler/verify/assura.py b/compiler/verify/assura.py
index 27949721..d3c605f3 100644
--- a/compiler/verify/assura.py
+++ b/compiler/verify/assura.py
@@ -25,10 +25,18 @@ import time
 import debug
 from globals import OPTS
 
+# Keep track of statistics
+num_drc_runs = 0
+num_lvs_runs = 0
+num_pex_runs = 0
+
 def run_drc(name, gds_name):
     """Run DRC check on a given top-level name which is
        implemented in gds_name."""
 
+    global num_drc_runs
+    num_drc_runs += 1
+    
     from tech import drc
     drc_rules = drc["drc_rules"]
     drc_runset = OPTS.openram_temp + name + ".rsf"
@@ -88,6 +96,10 @@ def run_drc(name, gds_name):
 def run_lvs(name, gds_name, sp_name):
     """Run LVS check on a given top-level name which is
        implemented in gds_name and sp_name. """
+
+    global num_lvs_runs
+    num_lvs_runs += 1
+    
     from tech import drc
     lvs_rules = drc["lvs_rules"]
     lvs_runset = OPTS.openram_temp + name + ".rsf"
@@ -170,3 +182,13 @@ def run_pex(name, gds_name, sp_name, output=None):
     """Run pex on a given top-level name which is
        implemented in gds_name and sp_name. """
     debug.error("PEX extraction not implemented with Assura.",-1)
+
+    global num_pex_runs
+    num_pex_runs += 1
+    
+def print_drc_stats():
+    debug.info(1,"DRC runs: {0}".format(num_drc_runs))
+def print_lvs_stats():
+    debug.info(1,"LVS runs: {0}".format(num_lvs_runs))
+def print_pex_stats():
+    debug.info(1,"PEX runs: {0}".format(num_pex_runs))
diff --git a/compiler/verify/calibre.py b/compiler/verify/calibre.py
index 38e92a2c..a7cd9290 100644
--- a/compiler/verify/calibre.py
+++ b/compiler/verify/calibre.py
@@ -65,10 +65,17 @@ import debug
 from globals import OPTS
 import subprocess
 
+# Keep track of statistics
+num_drc_runs = 0
+num_lvs_runs = 0
+num_pex_runs = 0
 
 def run_drc(cell_name, gds_name):
     """Run DRC check on a given top-level name which is
        implemented in gds_name."""
+    
+    global num_drc_runs
+    num_drc_runs += 1
 
     # the runset file contains all the options to run calibre
     from tech import drc
@@ -141,7 +148,10 @@ def run_lvs(cell_name, gds_name, sp_name, final_verification=False):
     """Run LVS check on a given top-level name which is
     implemented in gds_name and sp_name. Final verification will
     ensure that there are no remaining virtual conections. """
-
+    
+    global num_lvs_runs
+    num_lvs_runs += 1
+    
     from tech import drc
     lvs_rules = drc["lvs_rules"]
     lvs_runset = {
@@ -258,6 +268,10 @@ def run_lvs(cell_name, gds_name, sp_name, final_verification=False):
 def run_pex(cell_name, gds_name, sp_name, output=None):
     """Run pex on a given top-level name which is
        implemented in gds_name and sp_name. """
+
+    global num_pex_runs
+    num_pex_runs += 1
+    
     from tech import drc
     if output == None:
         output = name + ".pex.netlist"
@@ -354,3 +368,10 @@ def correct_port(name, output_file_name, ref_file_name):
     output_file.write(circuit_title)
     output_file.write(part2)
     output_file.close()
+
+def print_drc_stats():
+    debug.info(1,"DRC runs: {0}".format(num_drc_runs))
+def print_lvs_stats():
+    debug.info(1,"LVS runs: {0}".format(num_lvs_runs))
+def print_pex_stats():
+    debug.info(1,"PEX runs: {0}".format(num_pex_runs))
diff --git a/compiler/verify/magic.py b/compiler/verify/magic.py
index f438bad8..319d159a 100644
--- a/compiler/verify/magic.py
+++ b/compiler/verify/magic.py
@@ -64,6 +64,11 @@ import debug
 from globals import OPTS
 import subprocess
 
+# Keep track of statistics
+num_drc_runs = 0
+num_lvs_runs = 0
+num_pex_runs = 0
+
 def write_magic_script(cell_name, gds_name, extract=False):
     """ Write a magic script to perform DRC and optionally extraction. """
 
@@ -148,6 +153,9 @@ def write_netgen_script(cell_name, sp_name):
 def run_drc(cell_name, gds_name, extract=False):
     """Run DRC check on a cell which is implemented in gds_name."""
 
+    global num_drc_runs
+    num_drc_runs += 1
+
     write_magic_script(cell_name, gds_name, extract)
     
     # run drc
@@ -198,6 +206,9 @@ def run_lvs(cell_name, gds_name, sp_name, final_verification=False):
     implemented in gds_name and sp_name. Final verification will
     ensure that there are no remaining virtual conections. """
 
+    global num_lvs_runs
+    num_lvs_runs += 1
+    
     run_drc(cell_name, gds_name, extract=True)
     write_netgen_script(cell_name, sp_name)
     
@@ -270,6 +281,9 @@ def run_pex(name, gds_name, sp_name, output=None):
     """Run pex on a given top-level name which is
        implemented in gds_name and sp_name. """
 
+    global num_pex_runs
+    num_pex_runs += 1
+    
     debug.warning("PEX using magic not implemented.")
     return 1
 
@@ -337,3 +351,9 @@ def run_pex(name, gds_name, sp_name, output=None):
 
     return out_errors
 
+def print_drc_stats():
+    debug.info(1,"DRC runs: {0}".format(num_drc_runs))
+def print_lvs_stats():
+    debug.info(1,"LVS runs: {0}".format(num_lvs_runs))
+def print_pex_stats():
+    debug.info(1,"PEX runs: {0}".format(num_pex_runs))