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Switches to latching video interrupts until acknowledged.

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Seems to fix Cisco Heat, at least. I have no idea whether I'm latching the correct thing, whether IACK should clear both or only one, etc.
This commit is contained in:
Thomas Harte 2019-12-30 23:00:55 -05:00
parent 09513ec14c
commit 8e777c299f
1 changed files with 21 additions and 3 deletions
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24
Machines/Atari/ST/AtariST.cpp
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@ -176,7 +176,10 @@ class ConcreteMachine:
// An interrupt acknowledge, perhaps?
if(cycle.operation & Microcycle::InterruptAcknowledge) {
// Current implementation: everything other than 6 (i.e. the MFP is autovectored.
if((cycle.word_address()&7) != 6) {
const int interrupt_level = cycle.word_address()&7;
if(interrupt_level != 6) {
video_interrupts_pending_ &= ~interrupt_level;
update_interrupt_input();
mc68000_.set_is_peripheral_address(true);
return HalfCycles(0);
} else {
@ -552,12 +555,27 @@ class ConcreteMachine:
update_interrupt_input();
}
int video_interrupts_pending_ = 0;
bool previous_hsync_ = false, previous_vsync_ = false;
void update_interrupt_input() {
// Complete guess: set video interrupts pending if/when hsync of vsync
// go inactive. Reset upon IACK.
const bool hsync = video_.last_valid()->hsync();
const bool vsync = video_.last_valid()->vsync();
if(previous_hsync_ != hsync && previous_hsync_) {
video_interrupts_pending_ |= 2;
}
if(previous_vsync_ != vsync && previous_vsync_) {
video_interrupts_pending_ |= 4;
}
previous_vsync_ = vsync;
previous_hsync_ = hsync;
if(mfp_->get_interrupt_line()) {
mc68000_.set_interrupt_level(6);
} else if(video_->vsync()) {
} else if(video_interrupts_pending_ & 4) {
mc68000_.set_interrupt_level(4);
} else if(video_->hsync()) {
} else if(video_interrupts_pending_ & 2) {
mc68000_.set_interrupt_level(2);
} else {
mc68000_.set_interrupt_level(0);