From 6d6f91a02b6ff4b5459fe91fcae5b97ce915f7dd Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Mon, 19 Oct 2015 16:07:45 +0800
Subject: [PATCH] sim/core: fix Cat bitshift

---
 migen/sim/core.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/migen/sim/core.py b/migen/sim/core.py
index af3f3734f..157d63ff7 100644
--- a/migen/sim/core.py
+++ b/migen/sim/core.py
@@ -156,10 +156,11 @@ class Evaluator:
                 value -= 2**node.nbits
             self.modifications[node] = value
         elif isinstance(node, Cat):
+            nbits = 0
             for element in node.l:
+                value >>= nbits
                 nbits = len(element)
                 self.assign(element, value & (2**nbits-1))
-                value >>= nbits
         elif isinstance(node, _Slice):
             full_value = self.eval(node.value, True)
             # clear bits assigned to by the slice