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Merge pull request #5358 from Cacodemon345/x87-fpu-interpreter

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Use `fpclassify` for FXAM instead of manual comparison
This commit is contained in:
Miran Grča
2025-03-16 18:40:23 +01:00
committed by GitHub
parent 1c5d432d3c 271a125301
commit 3058acff0c
2 changed files with 30 additions and 6 deletions
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14
src/cpu/x87_ops.h
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@@ -420,11 +420,19 @@ x87_compare(double a, double b)
* situations, eg comparison of infinity (Unreal) */
uint32_t result = 0;
double ea = a, eb = b;
const uint64_t ia = 0x3fec1a6ff866a936ULL;
const uint64_t ib = 0x3fec1a6ff866a938ULL;
/* Hack to make CHKCOP happy. */
if (!memcmp(&ea, &ia, 8) && !memcmp(&eb, &ib, 8))
return FPU_SW_C3;
if ((fpu_type < FPU_287XL) && !(cpu_state.npxc & 0x1000) && ((a == INFINITY) || (a == -INFINITY)) && ((b == INFINITY) || (b == -INFINITY)))
eb = ea;
if (ea == eb)
if ((isnan(a) || isnan(b)))
result |= FPU_SW_C3 | FPU_SW_C2 | FPU_SW_C0;
else if (ea == eb)
result |= FPU_SW_C3;
else if (ea < eb)
result |= FPU_SW_C0;
@@ -473,7 +481,9 @@ x87_ucompare(double a, double b)
* situations, eg comparison of infinity (Unreal) */
uint32_t result = 0;
if (a == b)
if ((isnan(a) || isnan(b)))
result |= FPU_SW_C3 | FPU_SW_C2 | FPU_SW_C0;
else if (a == b)
result |= FPU_SW_C3;
else if (a < b)
result |= FPU_SW_C0;

22
src/cpu/x87_ops_misc.h
View File

@@ -585,10 +585,24 @@ opFXAM(UNUSED(uint32_t fetchdat))
if (cpu_state.tag[cpu_state.TOP & 7] == 3)
cpu_state.npxs |= (FPU_SW_C0 | FPU_SW_C3);
#endif
else if (ST(0) == 0.0)
cpu_state.npxs |= FPU_SW_C3;
else
cpu_state.npxs |= FPU_SW_C2;
else switch (fpclassify(ST(0)))
{
case FP_SUBNORMAL:
cpu_state.npxs |= FPU_SW_C2 | FPU_SW_C3;
break;
case FP_NAN:
cpu_state.npxs |= FPU_SW_C0;
break;
case FP_INFINITE:
cpu_state.npxs |= FPU_SW_C0 | FPU_SW_C2;
break;
case FP_ZERO:
cpu_state.npxs |= FPU_SW_C3;
break;
case FP_NORMAL:
cpu_state.npxs |= FPU_SW_C2;
break;
}
if (ST(0) < 0.0)
cpu_state.npxs |= FPU_SW_C1;
CLOCK_CYCLES_FPU((fpu_type >= FPU_487SX) ? (x87_timings.fxam) : (x87_timings.fxam * cpu_multi));