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dingusppc
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poweropcodes: improve lscbx emulation.

This commit is contained in:
Maxim Poliakovski 2024-02-24 22:44:45 +01:00
parent d71a213c4b
commit 45ccabb11d
1 changed files with 16 additions and 15 deletions
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31
cpu/ppc/poweropcodes.cpp
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@ -136,30 +136,28 @@ void dppc_interpreter::power_dozi() {
void dppc_interpreter::power_lscbx() {
ppc_grab_regsdab();
ppc_effective_address = reg_a ? (ppc_result_a + ppc_result_b) : ppc_result_b;
//ppc_result_d = 0xFFFFFFFF;
ppc_effective_address = reg_a ? ppc_result_a + ppc_result_b : ppc_result_b;
uint8_t return_value = 0;
uint32_t bytes_to_load = (ppc_state.spr[SPR::XER] & 0x7f);
uint8_t return_value = 0;
uint32_t bytes_to_load = (ppc_state.spr[SPR::XER] & 0x7F);
uint32_t bytes_copied = 0;
uint8_t matching_byte = (uint8_t)((ppc_state.spr[SPR::XER] & 0xFF00) >> 8);
uint8_t matching_byte = (uint8_t)(ppc_state.spr[SPR::XER] >> 8);
// for storing each byte
uint32_t bitmask = 0xFF000000;
uint8_t shift_amount = 24;
uint32_t bitmask = 0xFF000000;
uint8_t shift_amount = 24;
while (bytes_to_load > 0) {
return_value = mmu_read_vmem<uint8_t>(ppc_effective_address);
// return_value = mem_grab_byte(ppc_effective_address);
ppc_result_d = (ppc_result_d & ~(bitmask)) | (return_value << shift_amount);
ppc_store_result_regd();
if (bitmask == 0x000000FF) {
ppc_result_d = (ppc_result_d & ~bitmask) | (return_value << shift_amount);
if (!shift_amount) {
if (reg_d != reg_a && reg_d != reg_b)
ppc_store_result_regd();
reg_d = (reg_d + 1) & 31;
//ppc_result_d = 0xFFFFFFFF;
bitmask = 0xFF000000;
shift_amount = 24;
}
else {
} else {
bitmask >>= 8;
shift_amount -= 8;
}
@ -172,8 +170,11 @@ void dppc_interpreter::power_lscbx() {
break;
}
ppc_state.spr[SPR::XER] = (ppc_state.spr[SPR::XER] & 0xFFFFFF80) | bytes_copied;
// store partiallly loaded register if any
if (shift_amount != 24 && reg_d != reg_a && reg_d != reg_b)
ppc_store_result_regd();
ppc_state.spr[SPR::XER] = (ppc_state.spr[SPR::XER] & ~0x7F) | bytes_copied;
if (rc_flag)
ppc_changecrf0(ppc_result_d);