MIPS: Convert String array index/length hash to BitField.

src/mips/macro-assembler-mips.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 <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #include "v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
@@ skipping 3981 matching lines @@
   mov(v0, s0);
   jmp(&leave_exit_frame);
 }
 
 
 bool MacroAssembler::AllowThisStubCall(CodeStub* stub) {
   return has_frame_ || !stub->SometimesSetsUpAFrame();
 }
 
 
-void MacroAssembler::IndexFromHash(Register hash,
-                                   Register index) {
+void MacroAssembler::IndexFromHash(Register hash, Register index) {
   // If the hash field contains an array index pick it out. The assert checks
   // that the constants for the maximum number of digits for an array index
   // cached in the hash field and the number of bits reserved for it does not
   // conflict.
   ASSERT(TenToThe(String::kMaxCachedArrayIndexLength) <
          (1 << String::kArrayIndexValueBits));
-  // We want the smi-tagged index in key.  kArrayIndexValueMask has zeros in
-  // the low kHashShift bits.
-  STATIC_ASSERT(kSmiTag == 0);
-  Ext(hash, hash, String::kHashShift, String::kArrayIndexValueBits);
-  sll(index, hash, kSmiTagSize);
+  DecodeFieldToSmi<String::ArrayIndexValueBits>(index, hash);
 }
 
 
 void MacroAssembler::ObjectToDoubleFPURegister(Register object,
                                                FPURegister result,
                                                Register scratch1,
                                                Register scratch2,
                                                Register heap_number_map,
                                                Label* not_number,
                                                ObjectToDoubleFlags flags) {
@@ skipping 1701 matching lines @@
   }
   if (ms.shift() > 0) sra(result, result, ms.shift());
   srl(at, dividend, 31);
   Addu(result, result, Operand(at));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS