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Ensured that resetting the horizontal timer affects phase.

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This commit is contained in:
Thomas Harte 2016-05-22 16:29:53 -04:00
parent df93d7849d
commit 4c6d4d899d
1 changed files with 6 additions and 4 deletions
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10
Machines/Atari2600/Atari2600.cpp
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@ -378,6 +378,7 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
uint8_t returnValue = 0xff;
unsigned int cycles_run_for = 1;
unsigned int additional_pixels = 0;
// this occurs as a feedback loop — the 2600 requests ready, then performs the cycles_run_for
// leap to the end of ready only once ready is signalled — because on a 6502 ready doesn't take
@ -386,9 +387,10 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
if(operation == CPU6502::BusOperation::Ready) {
unsigned int distance_to_end_of_ready = horizontalTimerPeriod - _horizontalTimer;
cycles_run_for = distance_to_end_of_ready / 3;
additional_pixels = distance_to_end_of_ready % 3;
}
output_pixels(cycles_run_for * 3);
output_pixels(additional_pixels + cycles_run_for * 3);
// printf("/%d/", _horizontalTimer);
@ -471,8 +473,8 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
if(_horizontalTimer) set_ready_line(true);
break;
case 0x03:
_horizontalTimer = 0; // TODO: this should be delayed by four cycles, affecting phase;
// need to fix wait logic.
// Reset is delayed by four cycles.
_horizontalTimer = horizontalTimerPeriod - 4;
break;
case 0x04:
@ -699,7 +701,7 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
_piaTimerStatus |= 0xc0;
}
// output_pixels(cycles_run_for * 3);
// output_pixels(additional_pixels + cycles_run_for * 3);
return cycles_run_for;
}