Reduced the code sequence for testing for object type....

src/macro-assembler-ia32.cc

 // Copyright 2006-2008 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 288 matching lines @@
     mov(dst, x);
   }
 }
 
 
 void MacroAssembler::Set(const Operand& dst, const Immediate& x) {
   mov(dst, x);
 }
 
 
+void MacroAssembler::CmpObjectType(Register heap_object,
+                                   InstanceType type,
+                                   Register map) {
+  mov(map, FieldOperand(heap_object, HeapObject::kMapOffset));
+  CmpInstanceType(map, type);
+}
+
+
+void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
+  cmpb(FieldOperand(map, Map::kInstanceTypeOffset),
+       static_cast<int8_t>(type));
+}
+
+
 void MacroAssembler::FCmp() {
   fcompp();
   push(eax);
   fnstsw_ax();
   sahf();
   pop(eax);
 }
 
 
 void MacroAssembler::EnterFrame(StackFrame::Type type) {
@@ skipping 331 matching lines @@
 
 void MacroAssembler::TryGetFunctionPrototype(Register function,
                                              Register result,
                                              Register scratch,
                                              Label* miss) {
   // Check that the receiver isn't a smi.
   test(function, Immediate(kSmiTagMask));
   j(zero, miss, not_taken);
 
   // Check that the function really is a function.
-  mov(result, FieldOperand(function, HeapObject::kMapOffset));
-  movzx_b(scratch, FieldOperand(result, Map::kInstanceTypeOffset));
-  cmp(scratch, JS_FUNCTION_TYPE);
+  CmpObjectType(function, JS_FUNCTION_TYPE, result);
   j(not_equal, miss, not_taken);
 
   // Make sure that the function has an instance prototype.
   Label non_instance;
   movzx_b(scratch, FieldOperand(result, Map::kBitFieldOffset));
   test(scratch, Immediate(1 << Map::kHasNonInstancePrototype));
   j(not_zero, &non_instance, not_taken);
 
   // Get the prototype or initial map from the function.
   mov(result,
       FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
 
   // If the prototype or initial map is the hole, don't return it and
   // simply miss the cache instead. This will allow us to allocate a
   // prototype object on-demand in the runtime system.
   cmp(Operand(result), Immediate(Factory::the_hole_value()));
   j(equal, miss, not_taken);
 
   // If the function does not have an initial map, we're done.
   Label done;
-  mov(scratch, FieldOperand(result, HeapObject::kMapOffset));
-  movzx_b(scratch, FieldOperand(scratch, Map::kInstanceTypeOffset));
-  cmp(scratch, MAP_TYPE);
+  CmpObjectType(result, MAP_TYPE, scratch);
   j(not_equal, &done);
 
   // Get the prototype from the initial map.
   mov(result, FieldOperand(result, Map::kPrototypeOffset));
   jmp(&done);
 
   // Non-instance prototype: Fetch prototype from constructor field
   // in initial map.
   bind(&non_instance);
   mov(result, FieldOperand(result, Map::kConstructorOffset));
@@ skipping 331 matching lines @@
   // Indicate that code has changed.
   CPU::FlushICache(address_, size_);
 
   // Check that the code was patched as expected.
   ASSERT(masm_.pc_ == address_ + size_);
   ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
 }
 
 
 } }  // namespace v8::internal