Add packed add and subtract to IA32 and X64 assemblers

runtime/vm/assembler_x64.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_ASSEMBLER_X64_H_
 #define VM_ASSEMBLER_X64_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_x64.h directly; use assembler.h instead.
 #endif
@@ skipping 397 matching lines @@
   void movaps(XmmRegister dst, XmmRegister src);
 
   void movups(const Address& dst, XmmRegister src);
   void movups(XmmRegister dst, const Address& src);
 
   void addsd(XmmRegister dst, XmmRegister src);
   void subsd(XmmRegister dst, XmmRegister src);
   void mulsd(XmmRegister dst, XmmRegister src);
   void divsd(XmmRegister dst, XmmRegister src);
 
+  void addpl(XmmRegister dst, XmmRegister src);
+  void subpl(XmmRegister dst, XmmRegister src);
   void addps(XmmRegister dst, XmmRegister src);
   void subps(XmmRegister dst, XmmRegister src);
   void divps(XmmRegister dst, XmmRegister src);
   void mulps(XmmRegister dst, XmmRegister src);
   void minps(XmmRegister dst, XmmRegister src);
   void maxps(XmmRegister dst, XmmRegister src);
   void andps(XmmRegister dst, XmmRegister src);
   void andps(XmmRegister dst, const Address& src);
   void orps(XmmRegister dst, XmmRegister src);
   void notps(XmmRegister dst);
@@ skipping 507 matching lines @@
 }
 
 
 inline void Assembler::EmitOperandSizeOverride() {
   EmitUint8(0x66);
 }
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_X64_H_