X64 Win64: Reimplement fmod so that it works.

src/x64/macro-assembler-x64.h

 // Copyright 2009 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 368 matching lines @@
     Set(dst, reinterpret_cast<int64_t>(source));
   }
 
   void Move(const Operand& dst, Smi* source) {
     Set(dst, reinterpret_cast<int64_t>(source));
   }
 
   void Push(Smi* smi);
   void Test(const Operand& dst, Smi* source);
 
+  // Loads a smi as an integer onto the FPU stack.
+  void FLoadSmi(const Operand& src);
+
   // ---------------------------------------------------------------------------
   // Macro instructions
 
   // Load a register with a long value as efficiently as possible.
   void Set(Register dst, int64_t x);
   void Set(const Operand& dst, int64_t x);
 
   // Handle support
   void Move(Register dst, Handle<Object> source);
   void Move(const Operand& dst, Handle<Object> source);
@@ skipping 294 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_