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Merge pull request #7428 from MerryMage/rm-j-GenFrsqrte
GenFrsqrte: Reduce branches in fast-path and inline most behavior
This commit is contained in:
Mat M
GitHub
commit
0e0fd18d5e
@ -32,17 +32,14 @@ void CommonAsmRoutines::GenFrsqrte()
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// This function clobbers all three RSCRATCH.
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MOVQ_xmm(R(RSCRATCH), XMM0);
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// Negative and zero inputs set an exception and take the complex path.
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TEST(64, R(RSCRATCH), R(RSCRATCH));
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FixupBranch zero = J_CC(CC_Z, true);
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FixupBranch negative = J_CC(CC_S, true);
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// Extract exponent
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MOV(64, R(RSCRATCH_EXTRA), R(RSCRATCH));
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SHR(64, R(RSCRATCH_EXTRA), Imm8(52));
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// Zero and max exponents (non-normal floats) take the complex path.
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FixupBranch complex1 = J_CC(CC_Z, true);
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CMP(32, R(RSCRATCH_EXTRA), Imm32(0x7FF));
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FixupBranch complex2 = J_CC(CC_E, true);
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// Negatives, zeros, denormals, infinities and NaNs take the complex path.
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LEA(32, RSCRATCH2, MDisp(RSCRATCH_EXTRA, -1));
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CMP(32, R(RSCRATCH2), Imm32(0x7FE));
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FixupBranch complex = J_CC(CC_AE, true);
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SUB(32, R(RSCRATCH_EXTRA), Imm32(0x3FD));
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SAR(32, R(RSCRATCH_EXTRA), Imm8(1));
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@ -75,24 +72,53 @@ void CommonAsmRoutines::GenFrsqrte()
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MOVQ_xmm(XMM0, R(RSCRATCH2));
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RET();
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// Exception flags for zero input.
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SetJumpTarget(zero);
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SetJumpTarget(complex);
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AND(32, R(RSCRATCH_EXTRA), Imm32(0x7FF));
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CMP(32, R(RSCRATCH_EXTRA), Imm32(0x7FF));
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FixupBranch nan_or_inf = J_CC(CC_E);
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MOV(64, R(RSCRATCH2), R(RSCRATCH));
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SHL(64, R(RSCRATCH2), Imm8(1));
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FixupBranch nonzero = J_CC(CC_NZ);
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// +0.0 or -0.0
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TEST(32, PPCSTATE(fpscr), Imm32(FPSCR_ZX));
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FixupBranch skip_set_fx1 = J_CC(CC_NZ);
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OR(32, PPCSTATE(fpscr), Imm32(FPSCR_FX | FPSCR_ZX));
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FixupBranch complex3 = J();
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SetJumpTarget(skip_set_fx1);
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MOV(64, R(RSCRATCH2), Imm64(0x7FF0'0000'0000'0000));
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OR(64, R(RSCRATCH2), R(RSCRATCH));
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MOVQ_xmm(XMM0, R(RSCRATCH2));
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RET();
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// Exception flags for negative input.
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// SNaN or QNaN or +Inf or -Inf
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SetJumpTarget(nan_or_inf);
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MOV(64, R(RSCRATCH2), R(RSCRATCH));
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SHL(64, R(RSCRATCH2), Imm8(12));
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FixupBranch inf = J_CC(CC_Z);
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BTS(64, R(RSCRATCH), Imm8(51));
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MOVQ_xmm(XMM0, R(RSCRATCH));
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RET();
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SetJumpTarget(inf);
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BT(64, R(RSCRATCH), Imm8(63));
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FixupBranch negative = J_CC(CC_C);
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XORPD(XMM0, R(XMM0));
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RET();
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SetJumpTarget(nonzero);
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FixupBranch denormal = J_CC(CC_NC);
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// Negative sign
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SetJumpTarget(negative);
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TEST(32, PPCSTATE(fpscr), Imm32(FPSCR_VXSQRT));
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FixupBranch skip_set_fx2 = J_CC(CC_NZ);
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OR(32, PPCSTATE(fpscr), Imm32(FPSCR_FX | FPSCR_VXSQRT));
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SetJumpTarget(skip_set_fx1);
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SetJumpTarget(skip_set_fx2);
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SetJumpTarget(complex1);
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SetJumpTarget(complex2);
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SetJumpTarget(complex3);
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MOV(64, R(RSCRATCH2), Imm64(0x7FF8'0000'0000'0000));
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MOVQ_xmm(XMM0, R(RSCRATCH2));
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RET();
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SetJumpTarget(denormal);
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ABI_PushRegistersAndAdjustStack(QUANTIZED_REGS_TO_SAVE, 8);
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ABI_CallFunction(Common::ApproximateReciprocalSquareRoot);
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ABI_PopRegistersAndAdjustStack(QUANTIZED_REGS_TO_SAVE, 8);
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@ -13,3 +13,7 @@ add_dolphin_test(DSPAssemblyTest
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add_dolphin_test(ESFormatsTest IOS/ES/FormatsTest.cpp IOS/ES/TestBinaryData.cpp)
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add_dolphin_test(FileSystemTest IOS/FS/FileSystemTest.cpp)
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if(_M_X86)
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add_dolphin_test(PowerPCTest PowerPC/Jit64Common/Frsqrte.cpp)
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endif()
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101
Source/UnitTests/Core/PowerPC/Jit64Common/Frsqrte.cpp
Normal file
101
Source/UnitTests/Core/PowerPC/Jit64Common/Frsqrte.cpp
Normal file
@ -0,0 +1,101 @@
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// Copyright 2018 Dolphin Emulator Project
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// Licensed under GPLv2+
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// Refer to the license.txt file included.
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#include <cstring>
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#include <vector>
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#include "Common/BitUtils.h"
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#include "Common/CommonTypes.h"
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#include "Common/FloatUtils.h"
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#include "Common/x64ABI.h"
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#include "Core/PowerPC/Gekko.h"
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#include "Core/PowerPC/Jit64Common/Jit64AsmCommon.h"
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#include "Core/PowerPC/Jit64Common/Jit64Base.h"
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#include "Core/PowerPC/Jit64Common/Jit64PowerPCState.h"
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#include <gtest/gtest.h>
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class TestCommonAsmRoutines : public CommonAsmRoutines
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{
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public:
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TestCommonAsmRoutines()
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{
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using namespace Gen;
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AllocCodeSpace(4096);
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m_const_pool.Init(AllocChildCodeSpace(1024), 1024);
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const auto raw_frsqrte = reinterpret_cast<double (*)(double)>(AlignCode4());
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GenFrsqrte();
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wrapped_frsqrte = reinterpret_cast<u64 (*)(u64, UReg_FPSCR&)>(AlignCode4());
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ABI_PushRegistersAndAdjustStack(ABI_ALL_CALLEE_SAVED, 8, 16);
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// We know the frsqrte implementation only accesses the fpscr. We manufacture a
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// PPCSTATE pointer so we read/write to our provided fpscr argument instead.
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XOR(32, R(RPPCSTATE), R(RPPCSTATE));
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LEA(64, RSCRATCH, PPCSTATE(fpscr));
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SUB(64, R(ABI_PARAM2), R(RSCRATCH));
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MOV(64, R(RPPCSTATE), R(ABI_PARAM2));
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// Call
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MOVQ_xmm(XMM0, R(ABI_PARAM1));
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ABI_CallFunction(raw_frsqrte);
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MOVQ_xmm(R(ABI_RETURN), XMM0);
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ABI_PopRegistersAndAdjustStack(ABI_ALL_CALLEE_SAVED, 8, 16);
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RET();
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}
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u64 (*wrapped_frsqrte)(u64, UReg_FPSCR&);
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};
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TEST(Jit64, Frsqrte)
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{
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TestCommonAsmRoutines routines;
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const std::vector<u64> special_values{
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0x0000'0000'0000'0000, // positive zero
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0x0000'0000'0000'0001, // smallest positive denormal
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0x0000'0000'0100'0000,
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0x000F'FFFF'FFFF'FFFF, // largest positive denormal
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0x0010'0000'0000'0000, // smallest positive normal
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0x0010'0000'0000'0002,
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0x3FF0'0000'0000'0000, // 1.0
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0x7FEF'FFFF'FFFF'FFFF, // largest positive normal
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0x7FF0'0000'0000'0000, // positive infinity
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0x7FF0'0000'0000'0001, // first positive SNaN
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0x7FF7'FFFF'FFFF'FFFF, // last positive SNaN
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0x7FF8'0000'0000'0000, // first positive QNaN
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0x7FFF'FFFF'FFFF'FFFF, // last positive QNaN
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0x8000'0000'0000'0000, // negative zero
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0x8000'0000'0000'0001, // smallest negative denormal
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0x8000'0000'0100'0000,
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0x800F'FFFF'FFFF'FFFF, // largest negative denormal
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0x8010'0000'0000'0000, // smallest negative normal
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0x8010'0000'0000'0002,
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0xBFF0'0000'0000'0000, // -1.0
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0xFFEF'FFFF'FFFF'FFFF, // largest negative normal
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0xFFF0'0000'0000'0000, // negative infinity
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0xFFF0'0000'0000'0001, // first negative SNaN
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0xFFF7'FFFF'FFFF'FFFF, // last negative SNaN
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0xFFF8'0000'0000'0000, // first negative QNaN
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0xFFFF'FFFF'FFFF'FFFF, // last negative QNaN
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};
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UReg_FPSCR fpscr;
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for (u64 ivalue : special_values)
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{
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double dvalue = Common::BitCast<double>(ivalue);
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u64 expected = Common::BitCast<u64>(Common::ApproximateReciprocalSquareRoot(dvalue));
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u64 actual = routines.wrapped_frsqrte(ivalue, fpscr);
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printf("%016llx -> %016llx == %016llx\n", ivalue, actual, expected);
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EXPECT_EQ(expected, actual);
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}
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}
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