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Emulate division by zero edge cases (fixes #80)

This commit is contained in:
Jeffrey Pfau 2014-07-05 05:19:58 -07:00
parent 26c33b18e1
commit 2fd9ab1197
1 changed files with 34 additions and 12 deletions
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46
src/gba/gba-bios.c
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@ -101,6 +101,38 @@ static void _MidiKey2Freq(struct GBA* gba) {
cpu->gprs[0] = key / powf(2, (180.f - cpu->gprs[1] - cpu->gprs[2] / 256.f) / 12.f);
}
static void _Div(struct ARMCore* cpu, int32_t num, int32_t denom) {
if (denom != 0) {
div_t result = div(num, denom);
cpu->gprs[0] = result.quot;
cpu->gprs[1] = result.rem;
cpu->gprs[3] = abs(result.quot);
} else {
switch (num) {
case 0:
cpu->gprs[0] = 1;
cpu->gprs[1] = 0;
cpu->gprs[3] = 1;
break;
case 1:
cpu->gprs[0] = 1;
cpu->gprs[1] = 1;
cpu->gprs[3] = 1;
break;
case -1:
cpu->gprs[0] = -1;
cpu->gprs[1] = -1;
cpu->gprs[3] = 1;
break;
default:
// Technically this should hang, but that would be painful to emulate in HLE
cpu->gprs[0] = 0;
cpu->gprs[1] = 0;
cpu->gprs[3] = 0;
}
}
}
void GBASwi16(struct ARMCore* cpu, int immediate) {
struct GBA* gba = (struct GBA*) cpu->master;
GBALog(gba, GBA_LOG_DEBUG, "SWI: %02x", immediate);
@ -124,20 +156,10 @@ void GBASwi16(struct ARMCore* cpu, int immediate) {
ARMRaiseSWI(cpu);
break;
case 0x6:
{
div_t result = div(cpu->gprs[0], cpu->gprs[1]);
cpu->gprs[0] = result.quot;
cpu->gprs[1] = result.rem;
cpu->gprs[3] = abs(result.quot);
}
_Div(cpu, cpu->gprs[0], cpu->gprs[1]);
break;
case 0x7:
{
div_t result = div(cpu->gprs[1], cpu->gprs[0]);
cpu->gprs[0] = result.quot;
cpu->gprs[1] = result.rem;
cpu->gprs[3] = abs(result.quot);
}
_Div(cpu, cpu->gprs[1], cpu->gprs[0]);
break;
case 0x8:
cpu->gprs[0] = sqrt(cpu->gprs[0]);