Convert ElementsKind into a BitField

src/x64/macro-assembler-x64.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_X64
 
 #include "bootstrapper.h"
 #include "codegen.h"
@@ skipping 5174 matching lines @@
   ASSERT(!scratch1.is(scratch0));
   Register current = scratch0;
   Label loop_again;
 
   movp(current, object);
 
   // Loop based on the map going up the prototype chain.
   bind(&loop_again);
   movp(current, FieldOperand(current, HeapObject::kMapOffset));
   movp(scratch1, FieldOperand(current, Map::kBitField2Offset));
-  andp(scratch1, Immediate(Map::kElementsKindMask));
-  shrp(scratch1, Immediate(Map::kElementsKindShift));
+  DecodeField<Map::ElementsKindBits>(scratch1);
   cmpp(scratch1, Immediate(DICTIONARY_ELEMENTS));
   j(equal, found);
   movp(current, FieldOperand(current, Map::kPrototypeOffset));
   CompareRoot(current, Heap::kNullValueRootIndex);
   j(not_equal, &loop_again);
 }
 
 
 void MacroAssembler::TruncatingDiv(Register dividend, int32_t divisor) {
   ASSERT(!dividend.is(rax));
   ASSERT(!dividend.is(rdx));
   MultiplierAndShift ms(divisor);
   movl(rax, Immediate(ms.multiplier()));
   imull(dividend);
   if (divisor > 0 && ms.multiplier() < 0) addl(rdx, dividend);
   if (divisor < 0 && ms.multiplier() > 0) subl(rdx, dividend);
   if (ms.shift() > 0) sarl(rdx, Immediate(ms.shift()));
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64