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PPU: Implemented second PPU status flag ($213F)

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This commit is contained in:
Sour 2019-02-21 18:11:31 -05:00
parent 93b730b390
commit bcf41aca83
2 changed files with 21 additions and 2 deletions
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21
Core/Ppu.cpp
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@ -524,6 +524,7 @@ void Ppu::LatchLocationValues()
{
_horizontalLocation = _cycle;
_verticalLocation = _scanline;
_locationLatched = true;
}
uint8_t Ppu::Read(uint16_t addr)
@ -606,6 +607,7 @@ uint8_t Ppu::Read(uint16_t addr)
case 0x213E:
//STAT77 - PPU Status Flag and Version
//TODO open bus on bit 4
//"The high/low selector is reset to <20>elow<6F>f when $213f is read"
@ -615,9 +617,26 @@ uint8_t Ppu::Read(uint16_t addr)
return (
(_timeOver ? 0x80 : 0) |
(_rangeOver ? 0x40 : 0) |
0x01 //PPU chip version
0x01 //PPU (5c77) chip version
);
case 0x213F: {
//STAT78 - PPU Status Flag and Version
//TODO open bus on bit 5
uint8_t value = (
((_frameCount & 0x01) ? 0x80 : 0) |
(_locationLatched ? 0x40 : 0) |
//TODO (_isPal ? 0x10 : 0)
0x02 //PPU (5c78) chip version
);
if(_regs->GetIoPortOutput() & 0x80) {
_locationLatched = false;
}
return value;
}
default:
MessageManager::DisplayMessage("Debug", "Unimplemented register read: " + HexUtilities::ToHex(addr));
break;

2
Core/Ppu.h
View file

@ -113,9 +113,9 @@ private:
uint16_t _horizontalLocation = 0;
bool _horizontalLocToggle = false;
uint16_t _verticalLocation = 0;
bool _verticalLocationToggle = false;
bool _locationLatched = false;
uint16_t _mode7MatrixA = 0;
uint16_t _mode7MatrixB = 0;