Replace a set of Hydrogen instructions with rotate instructions on ARM

src/arm/simulator-arm.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 1480 matching lines @@
           *carry_out = (result < 0);
           result = 0;
         } else {
           *carry_out = false;
           result = 0;
         }
         break;
       }
 
       case ROR: {
-        UNIMPLEMENTED();
+        if (shift_amount == 0) {
+          *carry_out = c_flag_;
+        } else {
+          int32_t left = result >> shift_amount;

[Erik Corry, 2012/09/27 14:45:44]

How does this work with a negative input?

+          int32_t right = result << (32 - shift_amount);
+          result = right | left;
+          *carry_out = false;

[ulan, 2012/09/27 14:55:30]

The carry_out should contain the last shifted bit according to the spec.

+        }
         break;
       }
 

[ulan, 2012/09/27 14:55:30]

We can remove this empty line.

+
       default: {
         UNREACHABLE();
         break;
       }
     }
   }
   return result;
 }
 
 
@@ skipping 1869 matching lines @@
   uintptr_t address = *stack_slot;
   set_register(sp, current_sp + sizeof(uintptr_t));
   return address;
 }
 
 } }  // namespace v8::internal
 
 #endif  // USE_SIMULATOR
 
 #endif  // V8_TARGET_ARCH_ARM