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poweropcodes: fix div emulation.

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Clean up power_doz and power_maskir as well.
This commit is contained in:
Maxim Poliakovski 2023-12-01 20:38:29 +01:00
parent 07030378c8
commit 819d475181
1 changed files with 15 additions and 9 deletions
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24
cpu/ppc/poweropcodes.cpp
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@ -1,6 +1,6 @@
/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-21 divingkatae and maximum
Copyright (C) 2018-23 divingkatae and maximum
(theweirdo) spatium
(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
@ -78,8 +78,17 @@ void dppc_interpreter::power_clcs() {
void dppc_interpreter::power_div() {
ppc_grab_regsdab();
ppc_result_d = (ppc_result_a | ppc_state.spr[SPR::MQ]) / ppc_result_b;
ppc_state.spr[SPR::MQ] = (ppc_result_a | ppc_state.spr[SPR::MQ]) % ppc_result_b;
uint64_t dividend = ((uint64_t)ppc_result_a << 32) | ppc_state.spr[SPR::MQ];
int32_t divisor = (uint32_t)ppc_result_b;
if ((ppc_result_a == 0x80000000UL && divisor == -1) || !divisor) {
ppc_state.spr[SPR::MQ] = 0;
ppc_result_d = 0x80000000UL; // -2^31 aka INT32_MIN
} else {
ppc_result_d = dividend / divisor;
ppc_state.spr[SPR::MQ] = dividend % divisor;
}
if (oe_flag)
power_setsoov(ppc_result_b, ppc_result_a, ppc_result_d);
@ -104,11 +113,8 @@ void dppc_interpreter::power_divs() {
void dppc_interpreter::power_doz() {
ppc_grab_regsdab();
if (((int32_t)ppc_result_a) > ((int32_t)ppc_result_b)) {
ppc_result_d = 0;
} else {
ppc_result_d = ppc_result_b - ppc_result_a;
}
ppc_result_d = ((int32_t)ppc_result_a >= (int32_t)ppc_result_b) ? 0 :
ppc_result_b - ppc_result_a;
if (rc_flag)
ppc_changecrf0(ppc_result_d);
@ -199,7 +205,7 @@ void dppc_interpreter::power_maskg() {
void dppc_interpreter::power_maskir() {
ppc_grab_regssab();
ppc_result_a = (ppc_result_d & ppc_result_b) | (~(ppc_result_b) & ppc_result_a);
ppc_result_a = (ppc_result_a & ~ppc_result_b) | (ppc_result_d & ppc_result_b);
if (rc_flag)
ppc_changecrf0(ppc_result_a);