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Take a swing at adding an adjustment period.

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This commit is contained in:
Thomas Harte 2024-10-03 22:07:46 -04:00
parent 45549b5fcd
commit 35acf88847
1 changed files with 43 additions and 32 deletions
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75
Components/6845/CRTC6845.hpp
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@ -232,12 +232,21 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
if(character_counter_ == layout_.horizontal.start_sync) {
hsync_counter_ = 0;
bus_state_.hsync = true;
// printf("%d / %d [%d] + %d [v %d] => m:%d f:%d a:%d [sync: %d %d as %d]\n",
// row_counter_, bus_state_.row_address, row_end_hit,
// adjustment_counter_, layout_.vertical.adjust,
// eom_latched_, eof_latched_, is_in_adjustment_period_,
// bus_state_.hsync, bus_state_.vsync,
// layout_.vertical.start_sync);
}
// Check for end-of-line.
character_reset_history_ <<= 1;
if(character_total_hit) {
character_counter_ = 0;
character_is_visible_ = true;
character_reset_history_ |= 1;
} else {
character_counter_++;
}
@ -251,30 +260,46 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
// End-of-frame.
//
if(new_frame) {
is_in_adjustment_period_ = eom_latched_ = eof_latched_ = false;
} else {
eom_latched_ |= character_counter_ == 1 && row_end_hit && row_counter_ == layout_.vertical.total;
if(eom_latched_ && character_counter_ == 2) {
eof_latched_ |= adjustment_counter_ == layout_.vertical.adjust;
is_in_adjustment_period_ |= eom_latched_ && !eof_latched_;
if(character_total_hit) {
if(eof_latched_) {
eof_latched_ = eom_latched_ = is_in_adjustment_period_ = false;
adjustment_counter_ = 0;
} else if(is_in_adjustment_period_) {
adjustment_counter_ = (adjustment_counter_ + 1) & 31;
}
}
if(character_total_hit) {
if(is_in_adjustment_period_) {
adjustment_counter_ = (adjustment_counter_ + 1) & 31;
} else if(eof_latched_) {
is_in_adjustment_period_ = false;
adjustment_counter_ = 0;
}
if(character_reset_history_ & 2) {
eom_latched_ |= row_end_hit && row_counter_ == layout_.vertical.total;
}
if(character_reset_history_ & 4 && eom_latched_) {
is_in_adjustment_period_ |= adjustment_counter_ != layout_.vertical.adjust;
eof_latched_ |= adjustment_counter_ == layout_.vertical.adjust;
}
//
// Vertical.
//
// Sync.
const bool vsync_horizontal =
(!odd_field_ && !character_counter_) ||
(odd_field_ && character_counter_ == (layout_.horizontal.total >> 1));
if(vsync_horizontal) {
if((row_counter_ == layout_.vertical.start_sync && !bus_state_.row_address) || bus_state_.vsync) {
bus_state_.vsync = true;
vsync_counter_ = (vsync_counter_ + 1) & 0xf;
} else {
vsync_counter_ = 0;
}
if(vsync_counter_ == layout_.vertical.sync_lines) {
bus_state_.vsync = false;
}
}
// Row address.
if(character_total_hit) {
if(eof_latched_ ) {
bus_state_.row_address = 0;
@ -288,6 +313,7 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
}
}
// Row counter.
row_counter_ = next_row_counter_;
if(new_frame) {
next_row_counter_ = 0;
@ -297,23 +323,7 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
is_first_scanline_ &= !row_end_hit;
}
// Sync.
const bool vsync_horizontal =
(!odd_field_ && !character_counter_) ||
(odd_field_ && character_counter_ == (layout_.horizontal.total >> 1));
if(vsync_horizontal) {
if(row_counter_ == layout_.vertical.start_sync || bus_state_.vsync) {
bus_state_.vsync = true;
vsync_counter_ = (vsync_counter_ + 1) & 0xf;
} else {
vsync_counter_ = 0;
}
if(vsync_counter_ == layout_.vertical.sync_lines) {
bus_state_.vsync = false;
}
}
// Vertical display enable.
if(is_first_scanline_) {
line_is_visible_ = true;
} else if(line_is_visible_ && row_counter_ == layout_.vertical.displayed) {
@ -406,6 +416,7 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
int selected_register_ = 0;
uint8_t character_counter_ = 0;
uint32_t character_reset_history_ = 0;
uint8_t row_counter_ = 0, next_row_counter_ = 0;
uint8_t adjustment_counter_ = 0;