ARM: Implement MathPowStub and DoMathPowHalf.

Review URL: http://codereview.chromium.org/6613015

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7086 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/code-stubs-arm.cc

@@ -4056,6 +4056,106 @@ void GenericUnaryOpStub::Generate(MacroAssembler* masm) {
 }
 
 
+void MathPowStub::Generate(MacroAssembler* masm) {
+  Label call_runtime;
+
+  if (CpuFeatures::IsSupported(VFP3)) {
+    CpuFeatures::Scope scope(VFP3);
+
+    Label base_not_smi;
+    Label exponent_not_smi;
+    Label convert_exponent;
+
+    const Register base = r0;
+    const Register exponent = r1;
+    const Register heapnumbermap = r5;
+    const Register heapnumber = r6;
+    const DoubleRegister double_base = d0;
+    const DoubleRegister double_exponent = d1;
+    const DoubleRegister double_result = d2;
+    const SwVfpRegister single_scratch = s0;
+    const Register scratch = r9;
+    const Register scratch2 = r7;
+
+    __ LoadRoot(heapnumbermap, Heap::kHeapNumberMapRootIndex);
+    __ ldr(base, MemOperand(sp, 1 * kPointerSize));
+    __ ldr(exponent, MemOperand(sp, 0 * kPointerSize));
+
+    // Convert base to double value and store it in d0.
+    __ JumpIfNotSmi(base, &base_not_smi);
+    // Base is a Smi. Untag and convert it.
+    __ SmiUntag(base);
+    __ vmov(single_scratch, base);
+    __ vcvt_f64_s32(double_base, single_scratch);
+    __ b(&convert_exponent);
+
+    __ bind(&base_not_smi);
+    __ ldr(scratch, FieldMemOperand(base, JSObject::kMapOffset));
+    __ cmp(scratch, heapnumbermap);
+    __ b(ne, &call_runtime);
+    // Base is a heapnumber. Load it into double register.
+    __ vldr(double_base, FieldMemOperand(base, HeapNumber::kValueOffset));
+
+    __ bind(&convert_exponent);
+    __ JumpIfNotSmi(exponent, &exponent_not_smi);
+    __ SmiUntag(exponent);
+
+    // The base is in a double register and the exponent is
+    // an untagged smi. Allocate a heap number and call a
+    // C function for integer exponents. The register containing
+    // the heap number is callee-saved.
+    __ AllocateHeapNumber(heapnumber,
+                          scratch,
+                          scratch2,
+                          heapnumbermap,
+                          &call_runtime);
+    __ push(lr);
+    __ PrepareCallCFunction(3, scratch);
+    __ mov(r2, exponent);
+    __ vmov(r0, r1, double_base);
+    __ CallCFunction(ExternalReference::power_double_int_function(), 3);
+    __ pop(lr);
+    __ GetCFunctionDoubleResult(double_result);
+    __ vstr(double_result,
+            FieldMemOperand(heapnumber, HeapNumber::kValueOffset));
+    __ mov(r0, heapnumber);
+    __ Ret(2 * kPointerSize);
+
+    __ bind(&exponent_not_smi);
+    __ ldr(scratch, FieldMemOperand(exponent, JSObject::kMapOffset));
+    __ cmp(scratch, heapnumbermap);
+    __ b(ne, &call_runtime);
+    // Exponent is a heapnumber. Load it into double register.
+    __ vldr(double_exponent,
+            FieldMemOperand(exponent, HeapNumber::kValueOffset));
+
+    // The base and the exponent are in double registers.
+    // Allocate a heap number and call a C function for
+    // double exponents. The register containing
+    // the heap number is callee-saved.
+    __ AllocateHeapNumber(heapnumber,
+                          scratch,
+                          scratch2,
+                          heapnumbermap,
+                          &call_runtime);
+    __ push(lr);
+    __ PrepareCallCFunction(4, scratch);
+    __ vmov(r0, r1, double_base);
+    __ vmov(r2, r3, double_exponent);
+    __ CallCFunction(ExternalReference::power_double_double_function(), 4);
+    __ pop(lr);
+    __ GetCFunctionDoubleResult(double_result);
+    __ vstr(double_result,
+            FieldMemOperand(heapnumber, HeapNumber::kValueOffset));
+    __ mov(r0, heapnumber);
+    __ Ret(2 * kPointerSize);
+  }
+
+  __ bind(&call_runtime);
+  __ TailCallRuntime(Runtime::kMath_pow_cfunction, 2, 1);
+}
+
+
 void CEntryStub::GenerateThrowTOS(MacroAssembler* masm) {
   __ Throw(r0);
 }

src/arm/full-codegen-arm.cc

@@ -2858,7 +2858,8 @@ void FullCodeGenerator::EmitMathPow(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 2);
   VisitForStackValue(args->at(0));
   VisitForStackValue(args->at(1));
-  __ CallRuntime(Runtime::kMath_pow, 2);
+  MathPowStub stub;
+  __ CallStub(&stub);
   context()->Plug(r0);
 }
 

src/arm/lithium-arm.cc

@@ -1230,8 +1230,7 @@ LInstruction* LChunkBuilder::DoUnaryMathOperation(HUnaryMathOperation* instr) {
       case kMathRound:
         return AssignEnvironment(DefineAsRegister(result));
       case kMathPowHalf:
-        Abort("MathPowHalf LUnaryMathOperation not implemented");
-        return NULL;
+        return DefineSameAsFirst(result);
       default:
         UNREACHABLE();
         return NULL;

src/arm/lithium-codegen-arm.cc

@@ -745,10 +745,6 @@ void LCodeGen::DoCallStub(LCallStub* instr) {
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
       break;
     }
-    case CodeStub::MathPow: {
-      Abort("MathPowStub unimplemented.");
-      break;
-    }
     case CodeStub::NumberToString: {
       NumberToStringStub stub;
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
@@ -2646,6 +2642,22 @@ void LCodeGen::DoMathSqrt(LUnaryMathOperation* instr) {
 }
 
 
+void LCodeGen::DoMathPowHalf(LUnaryMathOperation* instr) {
+  DoubleRegister input = ToDoubleRegister(instr->InputAt(0));
+  Register scratch = scratch0();
+  SwVfpRegister single_scratch = double_scratch0().low();
+  DoubleRegister double_scratch = double_scratch0();
+  ASSERT(ToDoubleRegister(instr->result()).is(input));
+
+  // Add +0 to convert -0 to +0.
+  __ mov(scratch, Operand(0));
+  __ vmov(single_scratch, scratch);
+  __ vcvt_f64_s32(double_scratch, single_scratch);
+  __ vadd(input, input, double_scratch);
+  __ vsqrt(input, input);
+}
+
+
 void LCodeGen::DoPower(LPower* instr) {
   LOperand* left = instr->InputAt(0);
   LOperand* right = instr->InputAt(1);
@@ -2742,6 +2754,9 @@ void LCodeGen::DoUnaryMathOperation(LUnaryMathOperation* instr) {
     case kMathSqrt:
       DoMathSqrt(instr);
       break;
+    case kMathPowHalf:
+      DoMathPowHalf(instr);
+      break;
     case kMathCos:
       DoMathCos(instr);
       break;

src/arm/lithium-codegen-arm.h

@@ -210,6 +210,7 @@ class LCodeGen BASE_EMBEDDED {
   void DoMathFloor(LUnaryMathOperation* instr);
   void DoMathRound(LUnaryMathOperation* instr);
   void DoMathSqrt(LUnaryMathOperation* instr);
+  void DoMathPowHalf(LUnaryMathOperation* instr);
   void DoMathLog(LUnaryMathOperation* instr);
   void DoMathCos(LUnaryMathOperation* instr);
   void DoMathSin(LUnaryMathOperation* instr);

src/ia32/lithium-codegen-ia32.cc

@@ -748,11 +748,6 @@ void LCodeGen::DoCallStub(LCallStub* instr) {
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
       break;
     }
-    case CodeStub::MathPow: {
-      MathPowStub stub;
-      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
-      break;
-    }
     case CodeStub::NumberToString: {
       NumberToStringStub stub;
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);

src/x64/lithium-codegen-x64.cc

@@ -725,11 +725,6 @@ void LCodeGen::DoCallStub(LCallStub* instr) {
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
       break;
     }
-    case CodeStub::MathPow: {
-      MathPowStub stub;
-      CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
-      break;
-    }
     case CodeStub::NumberToString: {
       NumberToStringStub stub;
       CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);