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optimized Thumbulator range checks

This commit is contained in:
Thomas Jentzsch 2022-03-30 14:20:11 +02:00
parent 5e5a426a02
commit f6fcb8aa06
1 changed files with 5 additions and 40 deletions
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45
src/emucore/Thumbulator.cxx
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@ -552,61 +552,26 @@ bool Thumbulator::isInvalidROM(uInt32 addr)
{
const uInt32 romStart = configuration == ConfigureFor::DPCplus ? 0xc00 : 0x750; // was 0x800
switch(romSize)
{
case 64_KB:
if(!(addr >= romStart && addr <= 0x0FFFF))
return true;
break;
case 128_KB:
if(!(addr >= romStart && addr <= 0x1FFFF))
return true;
break;
case 256_KB:
if(!(addr >= romStart && addr <= 0x3FFFF))
return true;
break;
case 512_KB:
if(!(addr >= romStart && addr <= 0x7FFFF))
return true;
break;
default: // assuming 32 KB
if(!(addr >= romStart && addr <= 0x07FFF))
return true;
break;
}
return false;
return addr < romStart || addr >= romSize; // CDFJ+ allows ROM sizes larger than 32 KB
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bool Thumbulator::isInvalidRAM(uInt32 addr)
{
// Note: addr is already checked for RAM (0x4xxxxxxx)
switch(romSize)
switch(romSize) // CDFJ+ allows more than 8 KB RAM depending on ROM sizes
{
case 64_KB:
case 128_KB:
if(addr > 0x40003fff)
return true;
break;
return addr > 0x40003fff; // 16 KB
case 256_KB:
case 512_KB:
if(addr > 0x40007fff)
return true;
break;
return addr > 0x40007fff; // 32 KB
default: // assuming 32 KB
if(addr > 0x40001fff)
return true;
break;
return addr > 0x40001fff; // 8 KB
}
return false;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -