Change hash computation for transcendental cache to use arithmetic...

src/ia32/codegen-ia32.cc

 // Copyright 2010 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 10275 matching lines @@
   // Input is a HeapNumber. Push it on the FPU stack and load its
   // low and high words into ebx, edx.
   __ fld_d(FieldOperand(eax, HeapNumber::kValueOffset));
   __ mov(edx, FieldOperand(eax, HeapNumber::kExponentOffset));
   __ mov(ebx, FieldOperand(eax, HeapNumber::kMantissaOffset));
 
   __ bind(&loaded);
   // ST[0] == double value
   // ebx = low 32 bits of double value
   // edx = high 32 bits of double value
-  // Compute hash:
+  // Compute hash (the shifts are arithmetic):
   //   h = (low ^ high); h ^= h >> 16; h ^= h >> 8; h = h & (cacheSize - 1);
   __ mov(ecx, ebx);
   __ xor_(ecx, Operand(edx));
   __ mov(eax, ecx);
-  __ shr(eax, 16);
+  __ sar(eax, 16);
   __ xor_(ecx, Operand(eax));
   __ mov(eax, ecx);
-  __ shr(eax, 8);
+  __ sar(eax, 8);
   __ xor_(ecx, Operand(eax));
   ASSERT(IsPowerOf2(TranscendentalCache::kCacheSize));
   __ and_(Operand(ecx), Immediate(TranscendentalCache::kCacheSize - 1));
 
   // ST[0] == double value.
   // ebx = low 32 bits of double value.
   // edx = high 32 bits of double value.
   // ecx = TranscendentalCache::hash(double value).
   __ mov(eax,
          Immediate(ExternalReference::transcendental_cache_array_address()));
@@ skipping 3394 matching lines @@
   masm.GetCode(&desc);
   // Call the function from C++.
   return FUNCTION_CAST<MemCopyFunction>(buffer);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32