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Relocates the HSYNC start test, in order to pass Arnold's cpctest HSYNC start position conformance test.

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This commit is contained in:
Thomas Harte 2017-08-26 17:22:48 -04:00
parent 97f57a3948
commit 6c5a03187b
1 changed files with 13 additions and 13 deletions
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26
Components/6845/CRTC6845.hpp
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@ -87,19 +87,6 @@ template <class T> class CRTC6845 {
void run_for(Cycles cycles) {
int cyles_remaining = cycles.as_int();
while(cyles_remaining--) {
// check for start of horizontal sync
if(character_counter_ == registers_[2]) {
hsync_counter_ = 0;
bus_state_.hsync = true;
}
// check for end of horizontal sync; note that a sync time of zero will result in an immediate
// cancellation of the plan to perform sync
if(bus_state_.hsync) {
bus_state_.hsync = hsync_counter_ != (registers_[3] & 15);
hsync_counter_ = (hsync_counter_ + 1) & 15;
}
// check for end of visible characters
if(character_counter_ == registers_[1]) {
// TODO: consider skew in character_is_visible_. Or maybe defer until perform_bus_cycle?
@ -120,6 +107,19 @@ template <class T> class CRTC6845 {
character_counter_++;
}
// check for start of horizontal sync
if(character_counter_ == registers_[2]) {
hsync_counter_ = 0;
bus_state_.hsync = true;
}
// check for end of horizontal sync; note that a sync time of zero will result in an immediate
// cancellation of the plan to perform sync
if(bus_state_.hsync) {
bus_state_.hsync = hsync_counter_ != (registers_[3] & 15);
hsync_counter_ = (hsync_counter_ + 1) & 15;
}
perform_bus_cycle_phase2();
}
}