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Mitigate performance impact of respecting FP bit

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In #135 we switched from a static OpcodeGrabber table to a
curOpcodeGrabber pointer in ppc_main_opcode. This results in an extra
indirection (as far as generated assembly having an additional load),
which reduces execution speed.

Switch to making the opcode grabber into a parameter to
ppc_main_opcode, and make ppc_exec_inner keep it up to date (via an
EXEF_OPCODE exception flag).

Also fixes FPU instructions in ppctests - we now need to set the FP
MSR bit when initializing the CPU.
This commit is contained in:
Mihai Parparita
2025-01-25 17:46:25 -08:00
parent 7df166a99e
commit 134339ae9d
5 changed files with 49 additions and 25 deletions
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cpu/ppc/ppcexceptions.cpp
+6 -4
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@@ -57,7 +57,7 @@ void ppc_exception_handler(Except_Type exception_type, uint32_t srr1_bits) {
break;
case Except_Type::EXC_ISI:
if (exec_flags) {
if (exec_flags & ~EXEF_OPC_DECODER) {
ppc_state.spr[SPR::SRR0] = ppc_next_instruction_address;
} else {
ppc_state.spr[SPR::SRR0] = ppc_state.pc & 0xFFFFFFFCUL;
@@ -66,7 +66,7 @@ void ppc_exception_handler(Except_Type exception_type, uint32_t srr1_bits) {
break;
case Except_Type::EXC_EXT_INT:
if (exec_flags) {
if (exec_flags & ~EXEF_OPC_DECODER) {
ppc_state.spr[SPR::SRR0] = ppc_next_instruction_address;
} else {
ppc_state.spr[SPR::SRR0] = (ppc_state.pc & 0xFFFFFFFCUL) + 4;
@@ -90,7 +90,7 @@ void ppc_exception_handler(Except_Type exception_type, uint32_t srr1_bits) {
break;
case Except_Type::EXC_DECR:
if (exec_flags) {
if (exec_flags & ~EXEF_OPC_DECODER) {
ppc_state.spr[SPR::SRR0] = ppc_next_instruction_address;
} else {
ppc_state.spr[SPR::SRR0] = (ppc_state.pc & 0xFFFFFFFCUL) + 4;
@@ -114,10 +114,12 @@ void ppc_exception_handler(Except_Type exception_type, uint32_t srr1_bits) {
}
ppc_state.spr[SPR::SRR1] = (ppc_state.msr & 0x0000FF73) | srr1_bits;
uint32_t old_msr_val = ppc_state.msr;
ppc_state.msr &= 0xFFFB1041;
/* copy MSR[ILE] to MSR[LE] */
ppc_state.msr = (ppc_state.msr & ~MSR::LE) | !!(ppc_state.msr & MSR::ILE);
ppc_msr_did_change();
// Don't clobber the ppc_next_instruction_address value
ppc_msr_did_change(old_msr_val, false);
if (ppc_state.msr & MSR::IP) {
ppc_next_instruction_address |= 0xFFF00000;