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Adds a single-cycle M1 delay to the ColecoVision.

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This commit is contained in:
Thomas Harte 2019-02-27 22:01:30 -05:00
parent 28e69152d8
commit d2da55aa03
1 changed files with 7 additions and 7 deletions
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14
Machines/ColecoVision/ColecoVision.cpp
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@ -192,14 +192,14 @@ class ConcreteMachine:
// MARK: Z80::BusHandler // MARK: Z80::BusHandler
forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) { forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
// The SN76489 will use its ready line to trigger the Z80's wait for three // The SN76489 will use its ready line to trigger the Z80's wait for three
// cycles when accessed. Everything else runs at full speed. Short-circuit // cycles when accessed. M1 cycles are extended by a single cycle. Short-circuit
// that whole piece of communications by just accruing the time here if applicable. // that whole piece of communications by just accruing the time here if applicable.
const HalfCycles penalty( HalfCycles penalty(0);
( if(cycle.operation == CPU::Z80::PartialMachineCycle::Output && ((*cycle.address >> 5) & 7) == 7) {
cycle.operation == CPU::Z80::PartialMachineCycle::Output && penalty = HalfCycles(6);
((*cycle.address >> 5) & 7) == 7 } else if(cycle.operation == CPU::Z80::PartialMachineCycle::ReadOpcode) {
) ? 6 : 0 penalty = HalfCycles(2);
); }
const HalfCycles length = cycle.length + penalty; const HalfCycles length = cycle.length + penalty;
time_since_vdp_update_ += length; time_since_vdp_update_ += length;