diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index 8c2a3ed..914bd56 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -1552,6 +1552,14 @@
 }
 
 
+void X86Assembler::rep_movsw() {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0x66);
+  EmitUint8(0xF3);
+  EmitUint8(0xA5);
+}
+
+
 X86Assembler* X86Assembler::lock() {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xF0);