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Fix carry update for subfc(.) and subfco(.).

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This commit is contained in:
Maxim Poliakovski
2020-02-09 07:41:03 +01:00
parent 6f16ba8c57
commit 49002860ed
1 changed files with 13 additions and 4 deletions
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cpu/ppc/ppcopcodes.cpp
+13 -4
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@@ -165,6 +165,15 @@ void ppc_carry(uint32_t a, uint32_t b) {
}
}
inline void ppc_carry_sub(uint32_t a, uint32_t b) {
if (b >= a) { // TODO: ensure it works everywhere
ppc_state.ppc_spr[SPR::XER] |= 0x20000000UL;
}
else {
ppc_state.ppc_spr[SPR::XER] &= 0xDFFFFFFFUL;
}
}
//Affects the XER register's SO and OV Bits
inline void ppc_setsoov(uint32_t a, uint32_t b, uint32_t d) {
@@ -469,14 +478,14 @@ void ppc_subfodot() {
void ppc_subfc() {
ppc_grab_regsdab();
ppc_result_d = ppc_result_b - ppc_result_a;
ppc_carry(~ppc_result_a, ppc_result_d);
ppc_carry_sub(ppc_result_a, ppc_result_b);
ppc_store_result_regd();
}
void ppc_subfcdot() {
ppc_grab_regsdab();
ppc_result_d = ppc_result_b - ppc_result_a;
ppc_carry(~ppc_result_a, ppc_result_d);
ppc_carry_sub(ppc_result_a, ppc_result_b);
ppc_changecrf0(ppc_result_d);
ppc_store_result_regd();
}
@@ -485,7 +494,7 @@ void ppc_subfco() {
ppc_grab_regsdab();
ppc_result_d = ppc_result_b - ppc_result_a;
ppc_setsoov(ppc_result_b, ppc_result_a, ppc_result_d);
ppc_carry(~ppc_result_a, ppc_result_d);
ppc_carry_sub(ppc_result_a, ppc_result_b);
ppc_store_result_regd();
}
@@ -493,7 +502,7 @@ void ppc_subfcodot() {
ppc_grab_regsdab();
ppc_result_d = ppc_result_b - ppc_result_a;
ppc_setsoov(ppc_result_b, ppc_result_a, ppc_result_d);
ppc_carry(~ppc_result_a, ppc_result_d);
ppc_carry_sub(ppc_result_a, ppc_result_b);
ppc_changecrf0(ppc_result_d);
ppc_store_result_regd();
}