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Bug 1434843 : [MIPS] Make clampDoubleToUint8 less branchy; r=yuyin

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--HG--
extra : rebase_source : dca1d71f9085586c471ad1215812c2601cd8c67a
This commit is contained in:
Dragan Mladjenovic 2018-02-01 10:10:34 +01:00
parent 10aa4b8e60
commit 0bb7d5d8b2
2 changed files with 20 additions and 80 deletions
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48
js/src/jit/mips32/MacroAssembler-mips32.cpp
View File

@ -1392,49 +1392,19 @@ MacroAssemblerMIPSCompat::storeUnalignedDouble(const wasm::MemoryAccessDesc& acc
append(access, store.getOffset(), framePushed);
}
// Note: this function clobbers the input register.
void
MacroAssembler::clampDoubleToUint8(FloatRegister input, Register output)
{
MOZ_ASSERT(input != ScratchDoubleReg);
Label positive, done;
// <= 0 or NaN --> 0
as_roundwd(ScratchDoubleReg, input);
ma_li(ScratchRegister, Imm32(255));
as_mfc1(output, ScratchDoubleReg);
zeroDouble(ScratchDoubleReg);
branchDouble(DoubleGreaterThan, input, ScratchDoubleReg, &positive);
{
move32(Imm32(0), output);
jump(&done);
}
bind(&positive);
// Add 0.5 and truncate.
loadConstantDouble(0.5, ScratchDoubleReg);
addDouble(ScratchDoubleReg, input);
Label outOfRange;
branchTruncateDoubleMaybeModUint32(input, output, &outOfRange);
asMasm().branch32(Assembler::Above, output, Imm32(255), &outOfRange);
{
// Check if we had a tie.
convertInt32ToDouble(output, ScratchDoubleReg);
branchDouble(DoubleNotEqual, input, ScratchDoubleReg, &done);
// It was a tie. Mask out the ones bit to get an even value.
// See also js_TypedArray_uint8_clamp_double.
and32(Imm32(~1), output);
jump(&done);
}
// > 255 --> 255
bind(&outOfRange);
{
move32(Imm32(255), output);
}
bind(&done);
as_sltiu(SecondScratchReg, output, 255);
as_colt(DoubleFloat, ScratchDoubleReg, input);
// if res > 255; res = 255;
as_movz(output, ScratchRegister, SecondScratchReg);
// if !(input > 0); res = 0;
as_movf(output, zero);
}
// higher level tag testing code

48
js/src/jit/mips64/MacroAssembler-mips64.cpp
View File

@ -1345,49 +1345,19 @@ MacroAssemblerMIPS64Compat::storeUnalignedDouble(const wasm::MemoryAccessDesc& a
append(access, store.getOffset(), asMasm().framePushed());
}
// Note: this function clobbers the input register.
void
MacroAssembler::clampDoubleToUint8(FloatRegister input, Register output)
{
MOZ_ASSERT(input != ScratchDoubleReg);
Label positive, done;
// <= 0 or NaN --> 0
as_roundwd(ScratchDoubleReg, input);
ma_li(ScratchRegister, Imm32(255));
as_mfc1(output, ScratchDoubleReg);
zeroDouble(ScratchDoubleReg);
branchDouble(DoubleGreaterThan, input, ScratchDoubleReg, &positive);
{
move32(Imm32(0), output);
jump(&done);
}
bind(&positive);
// Add 0.5 and truncate.
loadConstantDouble(0.5, ScratchDoubleReg);
addDouble(ScratchDoubleReg, input);
Label outOfRange;
branchTruncateDoubleMaybeModUint32(input, output, &outOfRange);
asMasm().branch32(Assembler::Above, output, Imm32(255), &outOfRange);
{
// Check if we had a tie.
convertInt32ToDouble(output, ScratchDoubleReg);
branchDouble(DoubleNotEqual, input, ScratchDoubleReg, &done);
// It was a tie. Mask out the ones bit to get an even value.
// See also js_TypedArray_uint8_clamp_double.
and32(Imm32(~1), output);
jump(&done);
}
// > 255 --> 255
bind(&outOfRange);
{
move32(Imm32(255), output);
}
bind(&done);
as_sltiu(SecondScratchReg, output, 255);
as_colt(DoubleFloat, ScratchDoubleReg, input);
// if res > 255; res = 255;
as_movz(output, ScratchRegister, SecondScratchReg);
// if !(input > 0); res = 0;
as_movf(output, zero);
}
void