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Formalised set_interrupt_line's optional parameter as being a count of HalfCycles; corrected PartialMachineCycle.is_wait and effected the proper timing for counter reset on a ZX81.

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This commit is contained in:
Thomas Harte 2017-07-27 21:10:14 -04:00
parent 37950143fc
commit 8848ebbd4f
2 changed files with 10 additions and 7 deletions
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11
Machines/ZX8081/ZX8081.cpp
View File

@ -99,8 +99,12 @@ HalfCycles Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &c
} break;
case CPU::Z80::PartialMachineCycle::Interrupt:
// resetting event is M1 and IOREQ both simultaneously having leading edges;
// that happens 2 cycles before the end of INTACK. So the timer was reset and
// now has advanced twice.
horizontal_counter_ = HalfCycles(2);
*cycle.value = 0xff;
horizontal_counter_ = 0;
break;
case CPU::Z80::PartialMachineCycle::Refresh:
@ -109,7 +113,7 @@ HalfCycles Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &c
// final two cycles of an opcode fetch. Therefore communicate a transient signalling
// of the IRQ line if necessary.
if(!(address & 0x40)) {
set_interrupt_line(true, -2);
set_interrupt_line(true, Cycles(-2));
set_interrupt_line(false);
}
if(has_latched_video_byte_) {
@ -126,8 +130,7 @@ HalfCycles Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &c
}
break;
case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
case CPU::Z80::PartialMachineCycle::ReadOpcodeWait:
case CPU::Z80::PartialMachineCycle::ReadOpcode:
// Check for use of the fast tape hack.
if(use_fast_tape_hack_ && address == tape_trap_address_ && tape_player_.has_tape()) {
uint64_t prior_offset = tape_player_.get_tape()->get_offset();

6
Processors/Z80/Z80.hpp
View File

@ -104,7 +104,7 @@ struct PartialMachineCycle {
return operation <= Operation::BusAcknowledge;
}
inline bool is_wait() const {
return operation >= Operation::ReadWait && operation <= Operation::InterruptWait;
return operation >= Operation::ReadOpcodeWait && operation <= Operation::InterruptWait;
}
};
@ -1894,7 +1894,7 @@ template <class T> class Processor {
how many cycles before now the line changed state. The value may not be longer than the
current machine cycle. If called at any other time, this must be zero.
*/
void set_interrupt_line(bool value, int offset = 0) {
void set_interrupt_line(bool value, HalfCycles offset = 0) {
if(irq_line_ == value) return;
// IRQ requests are level triggered and masked.
@ -1908,7 +1908,7 @@ template <class T> class Processor {
// If this change happened at least one cycle ago then: (i) we're promised that this is a machine
// cycle per the contract on supplying an offset; and (ii) that means it happened before the lines
// were sampled. So adjust the most recent sample.
if(offset < 0) {
if(offset <= HalfCycles(-2)) {
last_request_status_ = (last_request_status_ & ~Interrupt::IRQ) | (request_status_ & Interrupt::IRQ);
}
}