ARM: Implement memcpy using NEON.

src/platform-posix.cc

 // Copyright 2012 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 322 matching lines @@
 OS::MemMoveFunction CreateMemMoveFunction();
 
 // Copy memory area. No restrictions.
 void OS::MemMove(void* dest, const void* src, size_t size) {
   if (size == 0) return;
   // Note: here we rely on dependent reads being ordered. This is true
   // on all architectures we currently support.
   (*memmove_function)(dest, src, size);
 }
 
-#endif  // V8_TARGET_ARCH_IA32
+#elif defined(V8_HOST_ARCH_ARM) && defined(V8_HOST_CAN_READ_UNALIGNED)
+void OS::MemCopyUint16Uint8Wrapper(uint16_t* dest,
+                               const uint8_t* src,
+                               size_t chars) {
+  uint16_t* limit = dest + chars;
+  while (dest < limit) {
+    *dest++ = static_cast<uint16_t>(*src++);
+  }
+}
+
+
+OS::MemCopyUint8Function OS::memcopy_uint8_function = &OS::MemCopyUint8Wrapper;
+OS::MemCopyUint16Uint8Function OS::memcopy_uint16_uint8_function =
+    &OS::MemCopyUint16Uint8Wrapper;
+// Defined in codegen-arm.cc.
+OS::MemCopyUint8Function CreateMemCopyUint8Function(
+    OS::MemCopyUint8Function stub);
+OS::MemCopyUint16Uint8Function CreateMemCopyUint16Uint8Function(
+    OS::MemCopyUint16Uint8Function stub);
+#endif
 
 
 void POSIXPostSetUp() {
 #if defined(V8_TARGET_ARCH_IA32)
   OS::MemMoveFunction generated_memmove = CreateMemMoveFunction();
   if (generated_memmove != NULL) {
     memmove_function = generated_memmove;
   }
+#elif defined(V8_HOST_ARCH_ARM) && defined(V8_HOST_CAN_READ_UNALIGNED)
+  OS::memcopy_uint8_function =
+      CreateMemCopyUint8Function(&OS::MemCopyUint8Wrapper);
+  OS::memcopy_uint16_uint8_function =
+      CreateMemCopyUint16Uint8Function(&OS::MemCopyUint16Uint8Wrapper);
 #endif
   init_fast_sin_function();
   init_fast_cos_function();
   init_fast_tan_function();
   init_fast_log_function();
   // fast_exp is initialized lazily.
   init_fast_sqrt_function();
 }
 
 // ----------------------------------------------------------------------------
@@ skipping 202 matching lines @@
   return ntohl(value);
 }
 
 
 Socket* OS::CreateSocket() {
   return new POSIXSocket();
 }
 
 
 } }  // namespace v8::internal