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Ensured the PIA timer resumes its normal tick rate after being read; fixed those spaces that had crept in where tabs should be.

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This commit is contained in:
Thomas Harte 2015-08-10 16:55:16 +01:00
parent 42677f5f83
commit aebf636528
3 changed files with 41 additions and 31 deletions
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22
Machines/Atari2600.cpp
View File

@ -354,15 +354,25 @@ int Machine::perform_bus_operation(CPU6502::BusOperation operation, uint16_t add
if ((address&0x1280) == 0x280) {
if(isReadOperation(operation)) {
switch(address & 0xf) {
case 0x04: returnValue &= _piaTimerValue >> _piaTimerShift; break;
case 0x05: returnValue &= _piaTimerStatus; _piaTimerStatus &= ~0x40; break;
case 0x04:
returnValue &= _piaTimerValue >> _piaTimerShift;
if(_writtenPiaTimerShift != _piaTimerShift) {
_piaTimerShift = _writtenPiaTimerShift;
_piaTimerValue <<= _writtenPiaTimerShift;
}
break;
case 0x05:
returnValue &= _piaTimerStatus;
_piaTimerStatus &= ~0x40;
break;
}
} else {
switch(address & 0x0f) {
case 0x04: _piaTimerShift = 0; _piaTimerValue = *value << 0; _piaTimerStatus &= ~0xc0; break;
case 0x05: _piaTimerShift = 3; _piaTimerValue = *value << 3; _piaTimerStatus &= ~0xc0; break;
case 0x06: _piaTimerShift = 6; _piaTimerValue = *value << 6; _piaTimerStatus &= ~0xc0; break;
case 0x07: _piaTimerShift = 10; _piaTimerValue = *value << 10; _piaTimerStatus &= ~0xc0; break;
case 0x04: _writtenPiaTimerShift = _piaTimerShift = 0; _piaTimerValue = *value << 0; _piaTimerStatus &= ~0xc0; break;
case 0x05: _writtenPiaTimerShift = _piaTimerShift = 3; _piaTimerValue = *value << 3; _piaTimerStatus &= ~0xc0; break;
case 0x06: _writtenPiaTimerShift = _piaTimerShift = 6; _piaTimerValue = *value << 6; _piaTimerStatus &= ~0xc0; break;
case 0x07: _writtenPiaTimerShift = _piaTimerShift = 10; _piaTimerValue = *value << 10; _piaTimerStatus &= ~0xc0; break;
}
}
// printf("Uncaught PIA %04x\n", address);

2
Machines/Atari2600.hpp
View File

@ -37,7 +37,7 @@ class Machine: public CPU6502::Processor<Machine> {
// the timer
unsigned int _piaTimerValue;
unsigned int _piaTimerShift;
unsigned int _piaTimerShift, _writtenPiaTimerShift;
uint8_t _piaTimerStatus;
// playfield registers