Implemented FastAsciiStringJoin in X64 full codegen.

src/x64/assembler-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 926 matching lines @@
   emitl(static_cast<int32_t>(displacement));
 }
 
 
 void Assembler::clc() {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   emit(0xF8);
 }
 
+void Assembler::cld() {
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  emit(0xFC);
+}
+
 void Assembler::cdq() {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   emit(0x99);
 }
 
 
 void Assembler::cmovq(Condition cc, Register dst, Register src) {
   if (cc == always) {
     movq(dst, src);
@@ skipping 2201 matching lines @@
   // specially coded on x64 means that it is a relative 32 bit address, as used
   // by branch instructions.
   return (1 << rmode_) & kApplyMask;
 }
 
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64