ARM: Implement native substring copying.

src/arm/assembler-arm.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 65 matching lines @@
 Register no_reg = { -1 };
 
 Register r0  = {  0 };
 Register r1  = {  1 };
 Register r2  = {  2 };
 Register r3  = {  3 };
 Register r4  = {  4 };
 Register r5  = {  5 };
 Register r6  = {  6 };
 Register r7  = {  7 };
-Register r8  = {  8 };
+Register r8  = {  8 };  // Used as context register.
 Register r9  = {  9 };
-Register r10 = { 10 };
+Register r10 = { 10 };  // Used as roots register.
 Register fp  = { 11 };
 Register ip  = { 12 };
 Register sp  = { 13 };
 Register lr  = { 14 };
 Register pc  = { 15 };
 
 
 CRegister no_creg = { -1 };
 
 CRegister cr0  = {  0 };
@@ skipping 1743 matching lines @@
     bind(&after_pool);
   }
 
   // Since a constant pool was just emitted, move the check offset forward by
   // the standard interval.
   next_buffer_check_ = pc_offset() + kCheckConstInterval;
 }
 
 
 } }  // namespace v8::internal