Add cld before doing rep movs.

Review URL: http://codereview.chromium.org/661368

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3996 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/codegen-ia32.cc

@@ -10922,6 +10922,7 @@ void StringStubBase::GenerateCopyCharactersREP(MacroAssembler* masm,
   // Copy from edi to esi using rep movs instruction.
   __ mov(scratch, count);
   __ sar(count, 2);  // Number of doublewords to copy.
+  __ cld();
   __ rep_movs();
 
   // Find number of bytes left.