Reviewers: Søren Gjesse,
Description:
ARM: Implement inline conversion of heap numbers to int32 values for
bitoperations.
For bit operations, values are truncated and converted to the range -2^31
through 2^31 - 1. This patch provides inlined handling of this conversion
for
all heap numbers.
Before, we were calling runtime for every heap number that did not fit into
a
signed int32.
Please review this at http://codereview.chromium.org/6658034/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/arm/code-stubs-arm.cc
Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index
bce0c518ab5c690baf1d11a3653b3abbd18eb073..1d429c8fc2650b82f8bc84c20119e416f88c2edb
100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -409,6 +409,7 @@ class FloatingPointHelper : public AllStatic {
Register heap_number_map,
Register scratch1,
Register scratch2,
+ Register scratch3,
DwVfpRegister double_scratch,
Label* not_int32);
@@ -612,6 +613,7 @@ void
FloatingPointHelper::LoadNumberAsInteger(MacroAssembler* masm,
Register heap_number_map,
Register scratch1,
Register scratch2,
+ Register scratch3,
DwVfpRegister double_scratch,
Label* not_int32) {
if (FLAG_debug_code) {
@@ -619,14 +621,88 @@ void
FloatingPointHelper::LoadNumberAsInteger(MacroAssembler* masm,
Heap::kHeapNumberMapRootIndex,
"HeapNumberMap register clobbered.");
}
- Label is_smi, done;
+ Label is_smi;
+ Label done;
+ Label not_in_int32_range;
+
__ JumpIfSmi(object, &is_smi);
__ ldr(scratch1, FieldMemOperand(object, HeapNumber::kMapOffset));
__ cmp(scratch1, heap_number_map);
__ b(ne, not_int32);
__ ConvertToInt32(
- object, dst, scratch1, scratch2, double_scratch, not_int32);
+ object, dst, scratch1, scratch2, double_scratch,
¬_in_int32_range);
__ jmp(&done);
+
+ __ bind(¬_in_int32_range);
+ if (CpuFeatures::IsSupported(VFP3)) {
+ CpuFeatures::Scope scope(VFP3);
+ __ vldr(double_scratch, FieldMemOperand(object,
HeapNumber::kValueOffset));
+ __ vmov(scratch1, scratch2, double_scratch);
+
+ // Register scratch1 contains mantissa word, scratch2 contains
+ // sign, exponent and mantissa.
+ __ and_(dst, scratch2, Operand(HeapNumber::kExponentMask));
+ __ mov(dst, Operand(dst, LSR, HeapNumber::kExponentShift));
+ __ sub(dst, dst, Operand(1023));
+
+ Label normal_exponent;
+ // Express exponent as delta to 31.
+ // If the delta is larger than 53, all bits would be shifted
+ // away, which means that we can return 0.
+ __ sub(dst, dst, Operand(31));
+ __ cmp(dst, Operand(53));
+ __ b(&normal_exponent, lt);
+ __ mov(dst, Operand(0));
+ __ jmp(&done);
+
+ __ bind(&normal_exponent);
+ const int kShiftBase = HeapNumber::kNonMantissaBitsInTopWord - 1;
+ // Calculate shift.
+ __ add(scratch3, dst, Operand(kShiftBase));
+
+ // Put implicit 1 before the mantissa part in scratch2 and
+ // shift the mantissa bits to the correct position.
+ __ orr(scratch2,
+ scratch2,
+ Operand(1 << HeapNumber::kMantissaBitsInTopWord));
+
+ // Save sign.
+ Register sign = dst;
+ __ and_(sign, scratch2, Operand(HeapNumber::kSignMask));
+
+ // Shift mantisssa bits in high word.
+ __ mov(scratch2, Operand(scratch2, LSL, scratch3));
+
+ // Replace the shifted bits with bits from the lower mantissa word.
+ Label pos_shift, neg_shift;
+ // scratch3 = 32 - scratch3.
+ __ mvn(scratch3, Operand(scratch3));
+ __ add(scratch3, scratch3, Operand(33));
+ __ cmp(scratch3, Operand(0));
+ __ b(&pos_shift, ge);
+
+ // Negate scratch3.
+ __ mvn(scratch3, Operand(scratch3));
+ __ add(scratch3, scratch3, Operand(1));
+ __ mov(scratch1, Operand(scratch1, LSL, scratch3));
+ __ jmp(&neg_shift);
+
+ __ bind(&pos_shift);
+ __ mov(scratch1, Operand(scratch1, LSR, scratch3));
+
+ __ bind(&neg_shift);
+ __ orr(scratch2, scratch2, Operand(scratch1));
+
+ // Restore sign if necessary.
+ __ tst(sign, sign);
+ __ mvn(scratch2, Operand(scratch2), LeaveCC, ne);
+ __ add(scratch2, scratch2, Operand(1), LeaveCC, ne);
+ __ mov(dst, scratch2);
+ __ jmp(&done);
+ } else {
+ __ jmp(not_int32);
+ }
+
__ bind(&is_smi);
__ SmiUntag(dst, object);
__ bind(&done);
@@ -3024,6 +3100,7 @@ void
TypeRecordingBinaryOpStub::GenerateFPOperation(MacroAssembler* masm,
Register right = r0;
Register scratch1 = r7;
Register scratch2 = r9;
+ Register scratch3 = r4;
ASSERT(smi_operands || (not_numbers != NULL));
if (smi_operands && FLAG_debug_code) {
@@ -3117,6 +3194,7 @@ void
TypeRecordingBinaryOpStub::GenerateFPOperation(MacroAssembler* masm,
heap_number_map,
scratch1,
scratch2,
+ scratch3,
d0,
not_numbers);
FloatingPointHelper::LoadNumberAsInteger(masm,
@@ -3125,6 +3203,7 @@ void
TypeRecordingBinaryOpStub::GenerateFPOperation(MacroAssembler* masm,
heap_number_map,
scratch1,
scratch2,
+ scratch3,
d0,
not_numbers);
}
@@ -3572,13 +3651,10 @@ void
TypeRecordingBinaryOpStub::GenerateInt32Stub(MacroAssembler* masm) {
void TypeRecordingBinaryOpStub::GenerateHeapNumberStub(MacroAssembler*
masm) {
- Label not_numbers, call_runtime;
+ Label call_runtime;
ASSERT(operands_type_ == TRBinaryOpIC::HEAP_NUMBER);
- GenerateFPOperation(masm, false, ¬_numbers, &call_runtime);
-
- __ bind(¬_numbers);
- GenerateTypeTransition(masm);
+ GenerateFPOperation(masm, false, &call_runtime, &call_runtime);
__ bind(&call_runtime);
GenerateCallRuntime(masm);
--
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