From 9d2902de9ea6b1c5f575a434a798c30b860cd942 Mon Sep 17 00:00:00 2001
From: mrg <mrg@ucsc.edu>
Date: Wed, 15 Apr 2020 15:55:49 -0700
Subject: [PATCH] Conditional well spacing

---
 compiler/modules/dff_buf.py | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/compiler/modules/dff_buf.py b/compiler/modules/dff_buf.py
index e42c01c0..c30f15b6 100644
--- a/compiler/modules/dff_buf.py
+++ b/compiler/modules/dff_buf.py
@@ -7,13 +7,13 @@
 #
 import debug
 import design
-from tech import drc,parameter
+from tech import parameter
 from tech import cell_properties as props
-from math import log
 from vector import vector
 from globals import OPTS
 from sram_factory import factory
 
+
 class dff_buf(design.design):
     """
     This is a simple buffered DFF. The output is buffered
@@ -107,13 +107,23 @@ class dff_buf(design.design):
         self.dff_inst.place(vector(0,0))
 
         # Add INV1 to the right
-        well_spacing = max(self.nwell_space,
-                           self.pwell_space,
-                           self.pwell_to_nwell)
-        self.inv1_inst.place(vector(self.dff_inst.rx() + well_spacing + self.well_extend_active,0))
+        well_spacing = 0
+        try:
+            well_spacing = max(well_spacing, self.nwell_space)
+        except AttributeError:
+            pass
+        try:
+            well_spacing = max(well_spacing, self.pwell_space)
+        except AttributeError:
+            pass
+        try:
+            well_spacing = max(well_spacing, self.pwell_to_nwell)
+        except AttributeError:
+            pass
+        self.inv1_inst.place(vector(self.dff_inst.rx() + well_spacing + self.well_extend_active, 0))
         
         # Add INV2 to the right
-        self.inv2_inst.place(vector(self.inv1_inst.rx(),0))
+        self.inv2_inst.place(vector(self.inv1_inst.rx(), 0))
         
     def route_wires(self):
         # Route dff q to inv1 a