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fix UB

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also misc changes to use more unsigned multiplication
also fix framebuffer resize
This commit is contained in:
RSDuck
2023-04-17 20:53:41 +02:00
parent 60a3fe24ed
commit 07bd9c06aa
3 changed files with 13 additions and 11 deletions
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16
src/GPU3D_Compute_shaders.h
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@ -299,11 +299,11 @@ uint Div64_32_32(uint numHi, uint numLo, uint den)
// there's a 1 in the MSB.
// We also shift numer by the same amount. This cannot overflow because numHi < den.
// The expression (-shift & 63) is the same as (64 - shift), except it avoids the UB of shifting
// by 64. <---- in C. I'm pretty sure shifts are masked in GLSL, but whatever.
// by 64. (it's also UB in GLSL!!!!)
uint shift = 31 - findMSB(den);
den <<= shift;
numHi <<= shift;
numHi |= (numLo >> (-shift & 63U)) & uint(-int(shift) >> 63);
numHi |= (numLo >> (-shift & 31U)) & uint(-int(shift) >> 31);
numLo <<= shift;
// Extract the low digits of the numerator and both digits of the denominator.
@ -347,12 +347,12 @@ int CalcYFactorY(YSpanSetup span, int i)
/*
maybe it would be better to do use a 32x32=64 multiplication?
*/
uint numLo = abs(i * span.W0n);
uint numLo = uint(abs(i)) * uint(span.W0n);
uint numHi = 0U;
numHi |= numLo >> (32-YFactorShift);
numHi |= numLo >> (32U-YFactorShift);
numLo <<= YFactorShift;
uint den = abs(i * span.W0d + (span.I1 - span.I0 - i) * span.W1d);
uint den = uint(abs(i)) * uint(span.W0d) + uint(abs(span.I1 - span.I0 - i)) * span.W1d;
if (den == 0)
{
@ -370,12 +370,12 @@ int CalcYFactorX(XSpanSetup span, int x)
if (span.X0 != span.X1)
{
uint numLo = uint(x) * span.W0;
uint numLo = uint(x) * uint(span.W0);
uint numHi = 0U;
numHi |= numLo >> (32-YFactorShift);
numHi |= numLo >> (32U-YFactorShift);
numLo <<= YFactorShift;
uint den = (uint(x) * span.W0) + (uint(span.X1 - span.X0 - x) * span.W1);
uint den = uint(x) * uint(span.W0) + uint(span.X1 - span.X0 - x) * uint(span.W1);
if (den == 0)
return 0;