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Reacts to no acknowledgement.

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This commit is contained in:
Thomas Harte 2019-10-31 21:00:05 -04:00
parent a5bbf54a27
commit 75e34b4215
2 changed files with 12 additions and 5 deletions
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2
Components/68901/MFP68901.hpp
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@ -37,7 +37,7 @@ class MFP68901: public ClockingHint::Source {
bool get_interrupt_line(); bool get_interrupt_line();
const int NoAcknowledgement = 0x100; static const int NoAcknowledgement = 0x100;
int acknowledge_interrupt(); int acknowledge_interrupt();
struct InterruptDelegate { struct InterruptDelegate {

15
Machines/AtariST/AtariST.cpp
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@ -307,6 +307,10 @@ class ConcreteMachine:
// MARK: MC68000::BusHandler // MARK: MC68000::BusHandler
using Microcycle = CPU::MC68000::Microcycle; using Microcycle = CPU::MC68000::Microcycle;
HalfCycles perform_bus_operation(const CPU::MC68000::Microcycle &cycle, int is_supervisor) { HalfCycles perform_bus_operation(const CPU::MC68000::Microcycle &cycle, int is_supervisor) {
// Just in case the last cycle was an interrupt acknowledge or bus error. TODO: find a better solution?
mc68000_.set_is_peripheral_address(false);
mc68000_.set_bus_error(false);
// Advance time. // Advance time.
advance_time(cycle.length); advance_time(cycle.length);
@ -323,15 +327,18 @@ class ConcreteMachine:
return HalfCycles(0); return HalfCycles(0);
} else { } else {
if(cycle.operation & Microcycle::SelectByte) { if(cycle.operation & Microcycle::SelectByte) {
cycle.value->halves.low = mfp_->acknowledge_interrupt(); const int interrupt = mfp_->acknowledge_interrupt();
if(interrupt != Motorola::MFP68901::MFP68901::NoAcknowledgement) {
cycle.value->halves.low = uint8_t(interrupt);
} else {
// TODO: this should take a while. Find out how long.
mc68000_.set_bus_error(true);
}
} }
return HalfCycles(0); return HalfCycles(0);
} }
} }
// Just in case the last cycle was an interrupt acknowledge. TODO: find a better solution?
mc68000_.set_is_peripheral_address(false);
auto address = cycle.word_address(); auto address = cycle.word_address();
// if(cycle.data_select_active()) printf("%c %06x\n", (cycle.operation & Microcycle::Read) ? 'r' : 'w', *cycle.address & 0xffffff); // if(cycle.data_select_active()) printf("%c %06x\n", (cycle.operation & Microcycle::Read) ? 'r' : 'w', *cycle.address & 0xffffff);
uint16_t *memory; uint16_t *memory;