Add a compare stub on ARM.

src/assembler.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 590 matching lines @@
 static double sub_two_doubles(double x, double y) {
   return x - y;
 }
 
 
 static double mul_two_doubles(double x, double y) {
   return x * y;
 }
 
 
+static int native_compare_doubles(double x, double y) {
+  if (x == y) return 0;
+  return x < y ? 1 : -1;
+}
+
+
 ExternalReference ExternalReference::double_fp_operation(
     Token::Value operation) {
   typedef double BinaryFPOperation(double x, double y);
   BinaryFPOperation* function = NULL;
   switch (operation) {
     case Token::ADD:
       function = &add_two_doubles;
       break;
     case Token::SUB:
       function = &sub_two_doubles;
       break;
     case Token::MUL:
       function = &mul_two_doubles;
       break;
     default:
       UNREACHABLE();
   }
   // Passing true as 2nd parameter indicates that they return an fp value.
   return ExternalReference(Redirect(FUNCTION_ADDR(function), true));
 }
 
 
+ExternalReference ExternalReference::compare_doubles() {
+  return ExternalReference(Redirect(FUNCTION_ADDR(native_compare_doubles),
+                                    false));
+}
+
+
 ExternalReferenceRedirector* ExternalReference::redirector_ = NULL;
 
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 ExternalReference ExternalReference::debug_break() {
   return ExternalReference(Redirect(FUNCTION_ADDR(Debug::Break)));
 }
 
 
 ExternalReference ExternalReference::debug_step_in_fp_address() {
   return ExternalReference(Debug::step_in_fp_addr());
 }
 #endif
 
 } }  // namespace v8::internal