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Merge pull request #6943 from lioncash/overflow

Interpreter/Jit64/JitArm64: Correct negative overflow handling for divw
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degasus committed May 28, 2018
2 parents a4d2553 + 6a4f12d commit 9e102e15843e6c28f27771fcaadb0ec5dcb7f65d
@@ -501,18 +501,18 @@ void Interpreter::divwx(UGeckoInstruction inst)
{
const s32 a = rGPR[inst.RA];
const s32 b = rGPR[inst.RB];
const bool overflow = b == 0 || ((u32)a == 0x80000000 && b == -1);
const bool overflow = b == 0 || (static_cast<u32>(a) == 0x80000000 && b == -1);
if (overflow)
{
if (((u32)a & 0x80000000) && b == 0)
if (a < 0)
rGPR[inst.RD] = UINT32_MAX;
else
rGPR[inst.RD] = 0;
}
else
{
rGPR[inst.RD] = (u32)(a / b);
rGPR[inst.RD] = static_cast<u32>(a / b);
}
if (inst.OE)
@@ -1223,7 +1223,8 @@ void Jit64::divwx(UGeckoInstruction inst)
s32 i = gpr.R(a).SImm32(), j = gpr.R(b).SImm32();
if (j == 0 || (i == (s32)0x80000000 && j == -1))
{
gpr.SetImmediate32(d, (i >> 31) ^ j);
const u32 result = i < 0 ? 0xFFFFFFFF : 0x00000000;
gpr.SetImmediate32(d, result);
if (inst.OE)
GenerateConstantOverflow(true);
}
@@ -1241,38 +1242,37 @@ void Jit64::divwx(UGeckoInstruction inst)
gpr.FlushLockX(EAX, EDX);
gpr.BindToRegister(d, (d == a || d == b), true);
MOV(32, R(EAX), gpr.R(a));
CDQ();
gpr.BindToRegister(b, true, false);
TEST(32, gpr.R(b), gpr.R(b));
FixupBranch not_div_by_zero = J_CC(CC_NZ);
MOV(32, gpr.R(d), R(EDX));
if (inst.OE)
{
GenerateConstantOverflow(true);
}
FixupBranch end1 = J();
SetJumpTarget(not_div_by_zero);
CMP(32, gpr.R(b), R(EDX));
FixupBranch not_div_by_neg_one = J_CC(CC_NZ);
const FixupBranch overflow = J_CC(CC_E);
CMP(32, R(EAX), Imm32(0x80000000));
const FixupBranch normal_path1 = J_CC(CC_NE);
CMP(32, gpr.R(b), Imm32(0xFFFFFFFF));
const FixupBranch normal_path2 = J_CC(CC_NE);
SetJumpTarget(overflow);
SAR(32, R(EAX), Imm8(31));
MOV(32, gpr.R(d), R(EAX));
NEG(32, gpr.R(d));
FixupBranch no_overflow = J_CC(CC_NO);
XOR(32, gpr.R(d), gpr.R(d));
if (inst.OE)
{
GenerateConstantOverflow(true);
}
FixupBranch end2 = J();
SetJumpTarget(not_div_by_neg_one);
const FixupBranch done = J();
SetJumpTarget(normal_path1);
SetJumpTarget(normal_path2);
CDQ();
IDIV(32, gpr.R(b));
MOV(32, gpr.R(d), R(EAX));
SetJumpTarget(no_overflow);
if (inst.OE)
{
GenerateConstantOverflow(false);
}
SetJumpTarget(end1);
SetJumpTarget(end2);
SetJumpTarget(done);
}
if (inst.Rc)
ComputeRC(gpr.R(d));
@@ -1164,17 +1164,17 @@ void JitArm64::divwx(UGeckoInstruction inst)
{
s32 imm_a = gpr.GetImm(a);
s32 imm_b = gpr.GetImm(b);
s32 imm_d;
if (imm_b == 0 || ((u32)imm_a == 0x80000000 && imm_b == -1))
u32 imm_d;
if (imm_b == 0 || (static_cast<u32>(imm_a) == 0x80000000 && imm_b == -1))
{
if (((u32)imm_a & 0x80000000) && imm_b == 0)
imm_d = -1;
if (imm_a < 0)
imm_d = 0xFFFFFFFF;
else
imm_d = 0;
}
else
{
imm_d = (u32)(imm_a / imm_b);
imm_d = static_cast<u32>(imm_a / imm_b);
}
gpr.SetImmediate(d, imm_d);
@@ -1217,9 +1217,7 @@ void JitArm64::divwx(UGeckoInstruction inst)
SetJumpTarget(slow1);
SetJumpTarget(slow2);
CMP(RB, 0);
CCMP(RA, 0, 0, CC_EQ);
CSETM(RD, CC_LT);
ASR(RD, RA, 31);
SetJumpTarget(done);

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