Convert ElementsKind into a BitField

src/ia32/macro-assembler-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #if V8_TARGET_ARCH_IA32
 
 #include "bootstrapper.h"
 #include "codegen.h"
@@ skipping 3399 matching lines @@
   Register current = scratch0;
   Label loop_again;
 
   // scratch contained elements pointer.
   mov(current, object);
 
   // Loop based on the map going up the prototype chain.
   bind(&loop_again);
   mov(current, FieldOperand(current, HeapObject::kMapOffset));
   mov(scratch1, FieldOperand(current, Map::kBitField2Offset));
-  and_(scratch1, Map::kElementsKindMask);
-  shr(scratch1, Map::kElementsKindShift);
+  DecodeField<Map::ElementsKindBits>(scratch1);
   cmp(scratch1, Immediate(DICTIONARY_ELEMENTS));
   j(equal, found);
   mov(current, FieldOperand(current, Map::kPrototypeOffset));
   cmp(current, Immediate(factory->null_value()));
   j(not_equal, &loop_again);
 }
 
 
 void MacroAssembler::TruncatingDiv(Register dividend, int32_t divisor) {
   ASSERT(!dividend.is(eax));
   ASSERT(!dividend.is(edx));
   MultiplierAndShift ms(divisor);
   mov(eax, Immediate(ms.multiplier()));
   imul(dividend);
   if (divisor > 0 && ms.multiplier() < 0) add(edx, dividend);
   if (divisor < 0 && ms.multiplier() > 0) sub(edx, dividend);
   if (ms.shift() > 0) sar(edx, ms.shift());
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32