Always 64-bit align floating point values in heap numbers....

src/ia32/macro-assembler-ia32.h

 // Copyright 2006-2009 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
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   // Try to get function prototype of a function and puts the value in
   // the result register. Checks that the function really is a
   // function and jumps to the miss label if the fast checks fail. The
   // function register will be untouched; the other registers may be
   // clobbered.
   void TryGetFunctionPrototype(Register function,
                                Register result,
                                Register scratch,
                                Label* miss);
 
+  // The double precision value in a heap number is always aligned even
+  // if the heap number object isn't.  This takes the address of a heap
+  // number and puts the address of its value in the result register.
+  // It is OK for the two registers to be identical.
+  void GenerateHeapNumberValueAddress(Register result, Register number) {
+    lea(result, Operand(number, 4 + HeapNumber::kValueMinimumOffset - kHeapObjectTag));
+    and_(result, -8);
+    //lea(result, Operand(number, HeapNumber::kValueMinimumOffset - kHeapObjectTag));
+  }
+
   // Generates code for reporting that an illegal operation has
   // occurred.
   void IllegalOperation(int num_arguments);
 
   // ---------------------------------------------------------------------------
   // Runtime calls
 
   // Call a code stub.
   void CallStub(CodeStub* stub);
 
@@ skipping 168 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_