From 33e8bce79d080bcf49855908ecaee6053697f6a7 Mon Sep 17 00:00:00 2001
From: Jesse Cirimelli-Low <jcirimel@ucsc.edu>
Date: Sun, 25 Apr 2021 01:22:36 -0700
Subject: [PATCH] dynamic predecode working

---
 compiler/modules/hierarchical_predecode.py | 50 ++++++++++++++++++++--
 1 file changed, 46 insertions(+), 4 deletions(-)

diff --git a/compiler/modules/hierarchical_predecode.py b/compiler/modules/hierarchical_predecode.py
index f83516d2..2da123a1 100644
--- a/compiler/modules/hierarchical_predecode.py
+++ b/compiler/modules/hierarchical_predecode.py
@@ -12,6 +12,10 @@ from vector import vector
 from sram_factory import factory
 from globals import OPTS
 from tech import layer_properties as layer_props
+from tech import layer_indices
+from tech import layer_stacks
+from tech import preferred_directions
+from tech import drc
 
 
 class hierarchical_predecode(design.design):
@@ -29,7 +33,7 @@ class hierarchical_predecode(design.design):
             self.cell_height = height
             
         self.column_decoder = column_decoder
-
+        self.input_and_rail_pos = []
         self.number_of_outputs = int(math.pow(2, self.number_of_inputs))
         super().__init__(name)
 
@@ -183,9 +187,9 @@ class hierarchical_predecode(design.design):
     def route(self):
 
         self.route_input_inverters()
-        self.route_output_inverters()
-        self.route_inputs_to_rails()
         self.route_input_ands()
+        self.route_output_inverters()
+        self.route_inputs_to_rails()    
         self.route_output_ands()
         self.route_vdd_gnd()
 
@@ -274,8 +278,45 @@ class hierarchical_predecode(design.design):
             # pins in the and gates.
             inv_out_pos = inv_out_pin.rc()
             y_offset = (inv_num + 1) * self.inv.height - self.output_layer_pitch
-            right_pos = inv_out_pos + vector(self.inv.width - self.inv.get_pin("Z").rx(), 0)
             rail_pos = vector(self.decode_rails[out_pin].cx(), y_offset)
+
+            # create via for dimensions
+            from_layer = self.output_layer
+            to_layer = self.bus_layer
+
+            cur_layer = from_layer
+            from_id = layer_indices[cur_layer]
+            to_id   = layer_indices[to_layer]
+
+            if from_id < to_id: # grow the stack up
+                search_id = 0
+                next_id = 2
+            else: # grow the stack down
+                search_id = 2
+                next_id = 0
+            
+            curr_stack = next(filter(lambda stack: stack[search_id] == cur_layer, layer_stacks), None)
+
+            via = factory.create(module_type="contact",
+                        layer_stack=curr_stack,
+                        dimensions=[1, 1],
+                        directions=self.bus_directions)
+
+            overlapping_pin_space = drc["{0}_to_{0}".format(self.output_layer)]
+            total_buffer_space = (overlapping_pin_space + via.height)
+            while(True):
+                drc_error = 0
+                for and_input in self.input_and_rail_pos:
+                    if and_input.x == rail_pos.x:
+                        if (abs(y_offset - and_input.y) < total_buffer_space) and (abs(y_offset - and_input.y) > via.height):
+                            drc_error = 1
+                if drc_error == 0:
+                    break
+                else:
+                    y_offset += drc["grid"]
+            rail_pos.y = y_offset
+            right_pos = inv_out_pos + vector(self.inv.width - self.inv.get_pin("Z").rx(), 0)
+            
             self.add_path(self.output_layer, [inv_out_pos, right_pos, vector(right_pos.x, y_offset), rail_pos])
 
             self.add_via_stack_center(from_layer=inv_out_pin.layer,
@@ -316,6 +357,7 @@ class hierarchical_predecode(design.design):
                                           to_layer=self.bus_layer,
                                           offset=rail_pos,
                                           directions=self.bus_directions)
+                self.input_and_rail_pos.append(rail_pos)
                 if gate_pin == "A":
                     direction = None
                 else: