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Corrects a counting error in the MSX.

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This commit is contained in:
Thomas Harte 2018-03-01 21:59:51 -05:00
parent 99d28a172b
commit b05d2b26bf
1 changed files with 15 additions and 14 deletions
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29
Machines/MSX/MSX.cpp
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@ -282,13 +282,6 @@ class ConcreteMachine:
// MARK: Z80::BusHandler
forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
if(time_until_interrupt_ > 0) {
time_until_interrupt_ -= cycle.length;
if(time_until_interrupt_ <= HalfCycles(0)) {
z80_.set_interrupt_line(true, time_until_interrupt_);
}
}
uint16_t address = cycle.address ? *cycle.address : 0x0000;
switch(cycle.operation) {
case CPU::Z80::PartialMachineCycle::ReadOpcode:
@ -468,13 +461,21 @@ class ConcreteMachine:
// Per the best information I currently have, the MSX inserts an extra cycle into each opcode read,
// but otherwise runs without pause.
HalfCycles addition((cycle.operation == CPU::Z80::PartialMachineCycle::ReadOpcode) ? 2 : 0);
time_since_vdp_update_ += cycle.length + addition;
time_since_ay_update_ += cycle.length + addition;
memory_slots_[0].cycles_since_update += cycle.length + addition;
memory_slots_[1].cycles_since_update += cycle.length + addition;
memory_slots_[2].cycles_since_update += cycle.length + addition;
memory_slots_[3].cycles_since_update += cycle.length + addition;
const HalfCycles addition((cycle.operation == CPU::Z80::PartialMachineCycle::ReadOpcode) ? 2 : 0);
const HalfCycles total_length = addition + cycle.length;
if(time_until_interrupt_ > 0) {
time_until_interrupt_ -= total_length;
if(time_until_interrupt_ <= HalfCycles(0)) {
z80_.set_interrupt_line(true, time_until_interrupt_);
}
}
time_since_vdp_update_ += total_length;
time_since_ay_update_ += total_length;
memory_slots_[0].cycles_since_update += total_length;
memory_slots_[1].cycles_since_update += total_length;
memory_slots_[2].cycles_since_update += total_length;
memory_slots_[3].cycles_since_update += total_length;
return addition;
}