Refactor smi tagging and untagging on IA-32.

bleeding_edge/src/ia32/macro-assembler-ia32.h

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 124 matching lines @@
   // Incoming register is heap_object and outgoing register is map.
   void CmpObjectType(Register heap_object, InstanceType type, Register map);
 
   // Compare instance type for map.
   void CmpInstanceType(Register map, InstanceType type);
 
   // FCmp is similar to integer cmp, but requires unsigned
   // jcc instructions (je, ja, jae, jb, jbe, je, and jz).
   void FCmp();
 
+  // Smi tagging support.
+  void SmiTag(Register reg) {
+    ASSERT(kSmiTag == 0);
+    shl(reg, kSmiTagSize);
+  }
+  void SmiUntag(Register reg) {
+    sar(reg, kSmiTagSize);
+  }
+
   // ---------------------------------------------------------------------------
   // Exception handling
 
   // Push a new try handler and link into try handler chain.  The return
   // address must be pushed before calling this helper.
   void PushTryHandler(CodeLocation try_location, HandlerType type);
 
   // Unlink the stack handler on top of the stack from the try handler chain.
   void PopTryHandler();
 
@@ skipping 322 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_MACRO_ASSEMBLER_IA32_H_