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

src/mips/macro-assembler-mips.h

 // 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.
 
 #ifndef V8_MIPS_MACRO_ASSEMBLER_MIPS_H_
 #define V8_MIPS_MACRO_ASSEMBLER_MIPS_H_
 
 #include "assembler.h"
 #include "mips/assembler-mips.h"
 #include "globals.h"
@@ skipping 1467 matching lines @@
                           DoubleRegister input_reg,
                           DoubleRegister temp_double_reg);
 
 
   void LoadInstanceDescriptors(Register map, Register descriptors);
   void EnumLength(Register dst, Register map);
   void NumberOfOwnDescriptors(Register dst, Register map);
 
   template<typename Field>
   void DecodeField(Register dst, Register src) {
-    static const int shift = Field::kShift;
-    static const int mask = Field::kMask >> shift;
-    static const int size = Field::kSize;
-    srl(dst, src, shift);
-    if (shift + size != 32) {
-      And(dst, dst, Operand(mask));
-    }
+    Ext(dst, src, Field::kShift, Field::kSize);
   }
 
   template<typename Field>
   void DecodeField(Register reg) {
     DecodeField<Field>(reg, reg);
   }
 
+  template<typename Field>
+  void DecodeFieldToSmi(Register dst, Register src) {
+    static const int shift = Field::kShift;
+    static const int mask = Field::kMask >> shift << kSmiTagSize;
+    STATIC_ASSERT((mask & (0x80000000u >> (kSmiTagSize - 1))) == 0);
+    STATIC_ASSERT(kSmiTag == 0);
+    if (shift < kSmiTagSize) {
+      sll(dst, src, kSmiTagSize - shift);
+      And(dst, dst, Operand(mask));
+    } else if (shift > kSmiTagSize) {
+      srl(dst, src, shift - kSmiTagSize);
+      And(dst, dst, Operand(mask));
+    } else {
+      And(dst, src, Operand(mask));
+    }
+  }
+
+  template<typename Field>
+  void DecodeFieldToSmi(Register reg) {
+    DecodeField<Field>(reg, reg);
+  }
+
   // Generates function and stub prologue code.
   void StubPrologue();
   void Prologue(bool code_pre_aging);
 
   // Activation support.
   void EnterFrame(StackFrame::Type type);
   void LeaveFrame(StackFrame::Type type);
 
   // Patch the relocated value (lui/ori pair).
   void PatchRelocatedValue(Register li_location,
@@ skipping 148 matching lines @@
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_MIPS_MACRO_ASSEMBLER_MIPS_H_