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ppcopcodes: Fix divw for MPC601.

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joevt 2024-12-02 00:56:02 -08:00 committed by dingusdev
parent b8af8d387c
commit b45b0a8df4
1 changed files with 8 additions and 2 deletions
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10
cpu/ppc/ppcopcodes.cpp
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@ -529,14 +529,20 @@ void dppc_interpreter::ppc_divw(uint32_t opcode) {
ppc_grab_regsdab(opcode);
if (!ppc_result_b) { // handle the "anything / 0" case
ppc_result_d = 0; // tested on G4 in Mac OS X 10.4 and Open Firmware.
if (is_601)
ppc_result_d = (int32_t(ppc_result_a) < 0) ? 1 : -1; // tested on 601 in Mac OS 9.1
else
ppc_result_d = 0; // tested on G4 in Mac OS X 10.4 and Open Firmware.
// ppc_result_d = (int32_t(ppc_result_a) < 0) ? -1 : 0; /* UNDOCUMENTED! */
if (ov)
ppc_state.spr[SPR::XER] |= XER::SO | XER::OV;
} else if (ppc_result_a == 0x80000000UL && ppc_result_b == 0xFFFFFFFFUL) {
ppc_result_d = 0; // tested on G4 in Mac OS X 10.4 and Open Firmware.
if (is_601)
ppc_result_d = 0x80000000U; // tested on 601 in Mac OS 9.1
else
ppc_result_d = 0; // tested on G4 in Mac OS X 10.4 and Open Firmware.
if (ov)
ppc_state.spr[SPR::XER] |= XER::SO | XER::OV;