Inline [] operator on one-byte strings.

runtime/vm/constants_x64.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_CONSTANTS_X64_H_
 #define VM_CONSTANTS_X64_H_
 
 namespace dart {
 
 enum Register {
@@ skipping 74 matching lines @@
 const Register kExceptionObjectReg = RAX;
 
 // Stack trace object is passed in this register to the catch handlers when
 // an exception is thrown.
 const Register kStackTraceObjectReg = RDX;
 
 enum ScaleFactor {
   TIMES_1 = 0,
   TIMES_2 = 1,
   TIMES_4 = 2,
-  TIMES_8 = 3
+  TIMES_8 = 3,
+  TIMES_HALF_WORD_SIZE = kWordSizeLog2 - 1
 };
 
 
 enum Condition {
   OVERFLOW      =  0,
   NO_OVERFLOW   =  1,
   BELOW         =  2,
   ABOVE_EQUAL   =  3,
   EQUAL         =  4,
   NOT_EQUAL     =  5,
@@ skipping 42 matching lines @@
 };
 
 
 // The largest multibyte nop we will emit.  This could go up to 15 if it
 // becomes important to us.
 const int MAX_NOP_SIZE = 8;
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_X64_H_