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This appears to be a more accurate take on 6845 address advancement — it is necessary that character output has finished for the line address to be updated.

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This commit is contained in:
Thomas Harte 2017-08-10 11:12:53 -04:00
parent 1b86bc21ab
commit a4c910f1de
1 changed files with 6 additions and 5 deletions
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11
Components/6845/CRTC6845.hpp
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@ -71,9 +71,6 @@ template <class T> class CRTC6845 {
// check for end-of-line
if(is_end_of_line) {
character_counter_ = 0;
character_is_visible_ = true;
// check for end of vertical sync
if(vsync_down_counter_) {
vsync_down_counter_--;
@ -94,7 +91,8 @@ template <class T> class CRTC6845 {
} else {
// advance vertical counter
if(bus_state_.row_address == registers_[9]) {
line_address_ = bus_state_.refresh_address;
if(!character_is_visible_)
line_address_ = bus_state_.refresh_address;
bus_state_.row_address = 0;
bool is_at_end_of_frame = line_counter_ == registers_[4];
@ -126,9 +124,12 @@ template <class T> class CRTC6845 {
}
} else {
bus_state_.row_address++;
bus_state_.refresh_address = line_address_;
}
bus_state_.refresh_address = line_address_;
}
character_counter_ = 0;
character_is_visible_ = true;
}
bus_state_.display_enable = character_is_visible_ && line_is_visible_;