X64: Implement fast charCodeAt.

src/x64/assembler-x64.cc

Index: src/x64/assembler-x64.cc
diff --git a/src/x64/assembler-x64.cc b/src/x64/assembler-x64.cc
index 5e70f9e0651bf61fe6dcb6946c0e24245417fb0b..b4fd678e1792b8b5046d894a7151d7d1987930cf 100644
--- a/src/x64/assembler-x64.cc
+++ b/src/x64/assembler-x64.cc
@@ -1244,6 +1244,26 @@ void Assembler::movzxbq(Register dst, const Operand& src) {
 }
 
 
+void Assembler::movzxbl(Register dst, const Operand& src) {
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  emit_optional_rex_32(dst, src);
+  emit(0x0F);
+  emit(0xB6);
+  emit_operand(dst, src);
+}
+
+
+void Assembler::movzxwl(Register dst, const Operand& src) {
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  emit_optional_rex_32(dst, src);
+  emit(0x0F);
+  emit(0xB7);
+  emit_operand(dst, src);
+}
+
+
 void Assembler::mul(Register src) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;