X86: Make string instructions work when rcx=0.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/arch/x86/isa/insts/general_purpose/string/load_string.py b/src/arch/x86/isa/insts/general_purpose/string/load_string.py
index 61525c2f2..8cf07fea6 100644
--- a/src/arch/x86/isa/insts/general_purpose/string/load_string.py
+++ b/src/arch/x86/isa/insts/general_purpose/string/load_string.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2007 The Hewlett-Packard Development Company
+# Copyright (c) 2007-2008 The Hewlett-Packard Development Company
 # All rights reserved.
 #
 # Redistribution and use of this software in source and binary forms,
@@ -67,6 +67,8 @@ def macroop LODS_M {
 };
 
 def macroop LODS_E_M {
+    and t0, rcx, rcx, flags=(EZF,), dataSize=asz
+    bri t0, label("end"), flags=(CEZF,)
     # Find the constant we need to either add or subtract from rdi
     ruflag t0, 10
     movi t3, t3, dsz, flags=(CEZF,), dataSize=asz
@@ -79,6 +81,7 @@ topOfLoop:
     subi rcx, rcx, 1, flags=(EZF,), dataSize=asz
     add rdi, rdi, t3, dataSize=asz
     bri t0, label("topOfLoop"), flags=(nCEZF,)
+end:
     fault "NoFault"
 };
 '''