X87: Simplify string copy in SubStringStub.

src/x87/code-stubs-x87.h

 // Copyright 2011 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_X87_CODE_STUBS_X87_H_
 #define V8_X87_CODE_STUBS_X87_H_
 
 #include "src/macro-assembler.h"
 #include "src/ic-inl.h"
 
@@ skipping 20 matching lines @@
   Major MajorKey() { return StoreBufferOverflow; }
   int MinorKey() { return 0; }
 };
 
 
 class StringHelper : public AllStatic {
  public:
   // Generate code for copying characters using the rep movs instruction.
   // Copies ecx characters from esi to edi. Copying of overlapping regions is
   // not supported.
-  static void GenerateCopyCharactersREP(MacroAssembler* masm,
-                                        Register dest,     // Must be edi.
-                                        Register src,      // Must be esi.
-                                        Register count,    // Must be ecx.
-                                        Register scratch,  // Neither of above.
-                                        bool ascii);
+  static void GenerateCopyCharacters(MacroAssembler* masm,
+                                     Register dest,
+                                     Register src,
+                                     Register count,
+                                     Register scratch,
+                                     String::Encoding encoding);
 
   // Generate string hash.
   static void GenerateHashInit(MacroAssembler* masm,
                                Register hash,
                                Register character,
                                Register scratch);
   static void GenerateHashAddCharacter(MacroAssembler* masm,
                                        Register hash,
                                        Register character,
                                        Register scratch);
@@ skipping 347 matching lines @@
   Register value_;
   Register address_;
   RememberedSetAction remembered_set_action_;
   RegisterAllocation regs_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X87_CODE_STUBS_X87_H_