Port code to load an integer directly from a heap number from ia32 to x64....

src/x64/assembler-x64.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 1041 matching lines @@
 
   void fild_s(const Operand& adr);
   void fild_d(const Operand& adr);
 
   void fist_s(const Operand& adr);
 
   void fistp_s(const Operand& adr);
   void fistp_d(const Operand& adr);
 
   void fisttp_s(const Operand& adr);
+  void fisttp_d(const Operand& adr);
 
   void fabs();
   void fchs();
 
   void fadd(int i);
   void fsub(int i);
   void fmul(int i);
   void fdiv(int i);
 
   void fisub_s(const Operand& adr);
@@ skipping 330 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_H_