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Switch to faster timer implementation; it seems to work.

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This commit is contained in:
Thomas Harte 2019-12-09 19:23:08 -05:00
parent e1c7a140d0
commit c2646a415f
1 changed files with 7 additions and 20 deletions
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23
Components/68901/MFP68901.cpp
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@ -178,29 +178,16 @@ void MFP68901::write(int address, uint8_t value) {
void MFP68901::run_for(HalfCycles time) { void MFP68901::run_for(HalfCycles time) {
cycles_left_ += time; cycles_left_ += time;
// TODO: this is the stupidest possible implementation. Improve. const int cycles = int(cycles_left_.flush<Cycles>().as_integral());
int cycles = int(cycles_left_.flush<Cycles>().as_integral());
while(cycles--) {
for(int c = 0; c < 4; ++c) { for(int c = 0; c < 4; ++c) {
if(timers_[c].mode >= TimerMode::Delay) { if(timers_[c].mode >= TimerMode::Delay) {
--timers_[c].divisor; const int dividend = (cycles + timers_[c].prescale - timers_[c].divisor);
if(!timers_[c].divisor) { const int decrements = dividend / timers_[c].prescale;
timers_[c].divisor = timers_[c].prescale; timers_[c].divisor = timers_[c].prescale - (dividend % timers_[c].prescale);
decrement_timer(c, 1); if(decrements) decrement_timer(c, decrements);
} }
} }
} }
}
// const int cycles = int(cycles_left_.flush<Cycles>().as_integral());
// for(int c = 0; c < 4; ++c) {
// if(timers_[c].mode >= TimerMode::Delay) {
// const int dividend = (cycles + timers_[c].prescale - timers_[c].divisor);
// const int decrements = dividend / timers_[c].prescale;
// timers_[c].divisor = timers_[c].prescale - (dividend % timers_[c].prescale);
// if(decrements) decrement_timer(c, decrements);
// }
// }
}
HalfCycles MFP68901::get_next_sequence_point() { HalfCycles MFP68901::get_next_sequence_point() {
return HalfCycles(-1); return HalfCycles(-1);