From 732f35a362776cc09d1eb0637f409863d03aae1a Mon Sep 17 00:00:00 2001
From: Matt Guthaus <mrg@ucsc.edu>
Date: Sun, 11 Nov 2018 12:25:53 -0800
Subject: [PATCH] Change channel router to route from bottom up to simplify
 code.

---
 compiler/base/hierarchy_layout.py | 15 ++++-----------
 compiler/sram_1bank.py            |  2 +-
 2 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/compiler/base/hierarchy_layout.py b/compiler/base/hierarchy_layout.py
index e745df57..229bb0f8 100644
--- a/compiler/base/hierarchy_layout.py
+++ b/compiler/base/hierarchy_layout.py
@@ -783,8 +783,8 @@ class layout(lef.lef):
         def vcg_pin_overlap(pin1, pin2, vertical):
             """ Check for vertical or horizontal overlap of the two pins """
 
-            # Pin 1 must be in the "TOP" set
-            x_overlap = pin1.by() > pin2.by() and abs(pin1.center().x-pin2.center().x)<pitch
+            # Pin 1 must be in the "BOTTOM" set
+            x_overlap = pin1.by() < pin2.by() and abs(pin1.center().x-pin2.center().x)<pitch
 
             # Pin 1 must be in the "LEFT" set
             y_overlap = pin1.lx() < pin2.lx() and abs(pin1.center().y-pin2.center().y)<pitch
@@ -832,13 +832,6 @@ class layout(lef.lef):
                     
         #FIXME: What if we have a cycle? 
 
-        # The starting offset is the first trunk at the top or left
-        # so we must offset from the lower left of the channel placement
-        # in the case of vertical tracks
-        if not vertical:
-            # This will start from top down
-            offset = offset + vector(0,len(nets)*pitch)
-
         # list of routes to do
         while vcg:
             #from pprint import pformat
@@ -862,13 +855,13 @@ class layout(lef.lef):
             # Remove the net from other constriants in the VCG
             vcg=remove_net_from_graph(net_name, vcg)
             
-            # Add the trunk routes from the bottom up or the left to right
+            # Add the trunk routes from the bottom up for horizontal or the left to right for vertical
             if vertical:
                 self.add_vertical_trunk_route(pin_list, offset, layer_stack, pitch)
                 offset += vector(pitch,0)
             else:
                 self.add_horizontal_trunk_route(pin_list, offset, layer_stack, pitch)
-                offset -= vector(0,pitch)
+                offset += vector(0,pitch)
 
 
     def create_vertical_channel_route(self, netlist, pins, offset, 
diff --git a/compiler/sram_1bank.py b/compiler/sram_1bank.py
index 260b26fc..16ff78d5 100644
--- a/compiler/sram_1bank.py
+++ b/compiler/sram_1bank.py
@@ -223,7 +223,7 @@ class sram_1bank(sram_base):
         """ Connect the output of the data flops to the write driver """
         # This is where the channel will start (y-dimension at least)
         for port in self.write_ports:
-            offset = self.data_dff_inst[port].ul() + vector(0, self.m1_pitch)
+            offset = self.data_dff_inst[port].ul() + vector(0, 2*self.m1_pitch)
 
             dff_names = ["dout_{}".format(x) for x in range(self.word_size)]
             bank_names = ["din{0}_{1}".format(port,x) for x in range(self.word_size)]