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Eliminates repetition of the unpacking of register 3 into a horizontal sync count.

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This commit is contained in:
Thomas Harte 2017-08-26 14:37:03 -04:00
parent e7ad79c79a
commit 7d7aa2f5d5
1 changed files with 8 additions and 7 deletions
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15
Components/6845/CRTC6845.hpp
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@ -87,16 +87,17 @@ template <class T> class CRTC6845 {
void run_for(Cycles cycles) {
int cyles_remaining = cycles.as_int();
while(cyles_remaining--) {
// check for end of horizontal sync
if(bus_state_.hsync) {
hsync_counter_ = (hsync_counter_ + 1) & 15;
bus_state_.hsync = hsync_counter_ != (registers_[3] & 15);
}
// check for start of horizontal sync
if(character_counter_ == registers_[2]) {
hsync_counter_ = 0;
if(registers_[3] & 15) bus_state_.hsync = true;
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