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PPU: Fixed V/H read toggle

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This commit is contained in:
Sour 2019-02-21 17:45:11 -05:00
parent 66aa5034a0
commit 93b730b390
1 changed files with 15 additions and 9 deletions
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24
Core/Ppu.cpp
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@ -571,32 +571,38 @@ uint8_t Ppu::Read(uint16_t addr)
return returnValue;
}
case 0x213B:{
case 0x213B: {
//CGDATAREAD - CGRAM Data read
uint8_t value = _cgram[_cgramAddress];
_cgramAddress = (_cgramAddress + 1) & (Ppu::CgRamSize - 1);
return value;
}
case 0x213C:
case 0x213C: {
//OPHCT - Horizontal Scanline Location
uint8_t value;
if(_horizontalLocToggle) {
//"Note that the value read is only 9 bits: bits 1-7 of the high byte are PPU2 Open Bus."
return ((_horizontalLocation & 0x100) >> 8) | ((addr >> 8) & 0xFE);
value = ((_horizontalLocation & 0x100) >> 8) | ((addr >> 8) & 0xFE);
} else {
return _horizontalLocation & 0xFF;
value = _horizontalLocation & 0xFF;
}
break;
_horizontalLocToggle = !_horizontalLocToggle;
return value;
}
case 0x213D:
case 0x213D: {
//OPVCT - Vertical Scanline Location
uint8_t value;
if(_verticalLocationToggle) {
//"Note that the value read is only 9 bits: bits 1-7 of the high byte are PPU2 Open Bus."
return ((_verticalLocation & 0x100) >> 8) | ((addr >> 8) & 0xFE);
value = ((_verticalLocation & 0x100) >> 8) | ((addr >> 8) & 0xFE);
} else {
return _verticalLocation & 0xFF;
value = _verticalLocation & 0xFF;
}
break;
_verticalLocationToggle = !_verticalLocationToggle;
return value;
}
case 0x213E: