ARM: Implement DoMathRound in the lithium code generator.

src/arm/lithium-codegen-arm.cc

 // Copyright 2011 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 2836 matching lines @@
   Label done;
   __ cmp(result, Operand(0));
   __ b(ne, &done);
   __ vmov(scratch1, input.high());
   __ tst(scratch1, Operand(HeapNumber::kSignMask));
   DeoptimizeIf(ne, instr->environment());
   __ bind(&done);
 }
 
 
+void LCodeGen::DoMathRound(LUnaryMathOperation* instr) {
+  DoubleRegister input = ToDoubleRegister(instr->InputAt(0));
+  Register result = ToRegister(instr->result());
+  Register scratch1 = scratch0();
+  Register scratch2 = result;
+  EmitVFPTruncate(kRoundToNearest,
+                  double_scratch0().low(),
+                  input,
+                  scratch1,
+                  scratch2);
+  DeoptimizeIf(ne, instr->environment());
+  __ vmov(result, double_scratch0().low());
+
+  // Test for -0.
+  Label done;
+  __ cmp(result, Operand(0));
+  __ b(ne, &done);
+  __ vmov(scratch1, input.high());
+  __ tst(scratch1, Operand(HeapNumber::kSignMask));
+  DeoptimizeIf(ne, instr->environment());
+  __ bind(&done);
+}
+
+
 void LCodeGen::DoMathSqrt(LUnaryMathOperation* instr) {
   DoubleRegister input = ToDoubleRegister(instr->InputAt(0));
   ASSERT(ToDoubleRegister(instr->result()).is(input));
   __ vsqrt(input, input);
 }
 
 
 void LCodeGen::DoUnaryMathOperation(LUnaryMathOperation* instr) {
   switch (instr->op()) {
     case kMathAbs:
       DoMathAbs(instr);
       break;
     case kMathFloor:
       DoMathFloor(instr);
       break;
+    case kMathRound:
+      DoMathRound(instr);
+      break;
     case kMathSqrt:
       DoMathSqrt(instr);
       break;
     default:
       Abort("Unimplemented type of LUnaryMathOperation.");
       UNREACHABLE();
   }
 }
 
 
@@ skipping 1085 matching lines @@
   ASSERT(!environment->HasBeenRegistered());
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal