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optimise away unneeded flag sets

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- especially useful for thumb code and larger max block sizes
- can still be improved upon
This commit is contained in:
RSDuck
2019-08-25 12:28:48 +02:00
parent 03ab7f1645
commit 5ea91b8a03
8 changed files with 243 additions and 104 deletions
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24
src/ARMJIT.cpp
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@ -126,6 +126,24 @@ void DeInit()
delete compiler;
}
void floodFillSetFlags(FetchedInstr instrs[], int start, u8 flags)
{
for (int j = start; j >= 0; j--)
{
u8 match = instrs[j].Info.WriteFlags & flags;
u8 matchMaybe = (instrs[j].Info.WriteFlags >> 4) & flags;
if (matchMaybe) // writes flags maybe
instrs[j].SetFlags |= matchMaybe;
if (match)
{
instrs[j].SetFlags |= match;
flags &= ~match;
if (!flags)
return;
}
}
}
CompiledBlock CompileBlock(ARM* cpu)
{
bool thumb = cpu->CPSR & 0x20;
@ -175,8 +193,14 @@ CompiledBlock CompileBlock(ARM* cpu)
instrs[i].Info = ARMInstrInfo::Decode(thumb, cpu->Num, instrs[i].Instr);
i++;
bool canCompile = compiler->CanCompile(thumb, instrs[i - 1].Info.Kind);
if (instrs[i - 1].Info.ReadFlags != 0 || !canCompile)
floodFillSetFlags(instrs, i - 2, canCompile ? instrs[i - 1].Info.ReadFlags : 0xF);
} while(!instrs[i - 1].Info.EndBlock && i < Config::JIT_MaxBlockSize);
floodFillSetFlags(instrs, i - 1, 0xF);
CompiledBlock block = compiler->CompileBlock(cpu, instrs, i);
if (cpu->Num == 0)