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MIPS: Fix register usage in softfloat code path.

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BUG=none
TEST=mjsunit/math-floor-part2.js

Review URL: https://codereview.chromium.org/12413032
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14099 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
palfia@homejinni.com 2013-03-28 21:17:02 +00:00
parent 443f85eed9
commit 797dd3053e
1 changed files with 14 additions and 29 deletions
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43
src/mips/code-stubs-mips.cc
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@ -684,6 +684,8 @@ void FloatingPointHelper::LoadNumber(MacroAssembler* masm,
Register scratch1,
Register scratch2,
Label* not_number) {
ASSERT(!object.is(dst1) && !object.is(dst2));
__ AssertRootValue(heap_number_map,
Heap::kHeapNumberMapRootIndex,
"HeapNumberMap register clobbered.");
@ -878,6 +880,10 @@ void FloatingPointHelper::LoadNumberAsInt32Double(MacroAssembler* masm,
ASSERT(!heap_number_map.is(object) &&
!heap_number_map.is(scratch1) &&
!heap_number_map.is(scratch2));
// ARM uses pop/push and Ldlr to save dst_* and probably object registers in
// softfloat path. On MIPS there is no ldlr, 1st lw instruction may overwrite
// object register making the 2nd lw invalid.
ASSERT(!object.is(dst_mantissa) && !object.is(dst_exponent));
Label done, obj_is_not_smi;
@ -914,49 +920,24 @@ void FloatingPointHelper::LoadNumberAsInt32Double(MacroAssembler* masm,
if (destination == kCoreRegisters) {
__ Move(dst_mantissa, dst_exponent, double_dst);
}
} else {
ASSERT(!scratch1.is(object) && !scratch2.is(object));
// Load the double value in the destination registers.
bool save_registers = object.is(dst_mantissa) || object.is(dst_exponent);
if (save_registers) {
// Save both output registers, because the other one probably holds
// an important value too.
__ Push(dst_exponent, dst_mantissa);
}
__ lw(dst_exponent, FieldMemOperand(object, HeapNumber::kExponentOffset));
__ lw(dst_mantissa, FieldMemOperand(object, HeapNumber::kMantissaOffset));
// Check for 0 and -0.
Label zero;
__ And(scratch1, dst_exponent, Operand(~HeapNumber::kSignMask));
__ Or(scratch1, scratch1, Operand(dst_mantissa));
__ Branch(&zero, eq, scratch1, Operand(zero_reg));
__ Branch(&done, eq, scratch1, Operand(zero_reg));
// Check that the value can be exactly represented by a 32-bit integer.
// Jump to not_int32 if that's not the case.
Label restore_input_and_miss;
DoubleIs32BitInteger(masm, dst_exponent, dst_mantissa, scratch1, scratch2,
&restore_input_and_miss);
not_int32);
// dst_* were trashed. Reload the double value.
if (save_registers) {
__ Pop(dst_exponent, dst_mantissa);
}
__ lw(dst_exponent, FieldMemOperand(object, HeapNumber::kExponentOffset));
__ lw(dst_mantissa, FieldMemOperand(object, HeapNumber::kMantissaOffset));
__ Branch(&done);
__ bind(&restore_input_and_miss);
if (save_registers) {
__ Pop(dst_exponent, dst_mantissa);
}
__ Branch(not_int32);
__ bind(&zero);
if (save_registers) {
__ Drop(2);
}
}
__ bind(&done);
@ -2707,16 +2688,20 @@ void BinaryOpStub_GenerateFPOperation(MacroAssembler* masm,
masm, destination, right, f14, a2, a3, heap_number_map,
scratch1, scratch2, fail);
}
// Use scratch3 as left in LoadNumber functions to avoid overwriting of
// left (a0) register.
__ mov(scratch3, left);
// Load left operand to f12 or a0/a1. This keeps a0/a1 intact if it
// jumps to |miss|.
if (left_type == BinaryOpIC::INT32) {
FloatingPointHelper::LoadNumberAsInt32Double(
masm, left, destination, f12, f16, a0, a1, heap_number_map,
masm, scratch3, destination, f12, f16, a0, a1, heap_number_map,
scratch1, scratch2, f2, miss);
} else {
Label* fail = (left_type == BinaryOpIC::NUMBER) ? miss : not_numbers;
FloatingPointHelper::LoadNumber(
masm, destination, left, f12, a0, a1, heap_number_map,
masm, destination, scratch3, f12, a0, a1, heap_number_map,
scratch1, scratch2, fail);
}
}