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Merge pull request #1455 from TomHarte/MatchBefore
Restructure loop to perform events AT time, not upon reaching it.
This commit is contained in:
Thomas Harte
GitHub
commit
61086d5360
@ -223,6 +223,148 @@ public:
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subcycles_ += cycles * 2;
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auto ticks_remaining = subcycles_.divide(is_ntsc_ ? Cycles(4) : Cycles(5)).as<int>();
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while(ticks_remaining) {
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//
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// Check for events: (i) deferred; ...
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//
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if(delayed_events_) {
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if(delayed_events_ & uint64_t(DelayedEvent::Latch)) {
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if(char_pos_latch_ && vertical_sub_active_) {
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character_position_reload_ = character_position_;
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}
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char_pos_latch_ = vertical_sub_count_ == 6;
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if(char_pos_latch_ && enable_display_) {
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video_counter_reload_ = video_counter_;
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}
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}
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if(delayed_events_ & uint64_t(DelayedEvent::Flash)) {
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if(vertical_counter_ == 205) {
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++flash_count_;
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flash_mask_ = (flash_count_ & 0x10) ? 0xff : 0x00;
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}
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}
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if(delayed_events_ & uint64_t(DelayedEvent::IncrementVerticalLine)) {
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vertical_counter_ = next_vertical_counter_;
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bad_line2_ = bad_line();
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}
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if(delayed_events_ & uint64_t(DelayedEvent::IncrementVerticalSub)) {
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if(!video_line_) {
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vertical_sub_count_ = 7; // TODO: should be between cycle 0xc8 and 0xca?
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} else if(display_enable_ && vertical_sub_active_) {
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vertical_sub_count_ = (vertical_sub_count_ + 1) & 7;
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}
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}
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if(delayed_events_ & uint64_t(DelayedEvent::CounterReset)) {
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horizontal_counter_ = 0;
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}
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delayed_events_ &= ~uint64_t(DelayedEvent::Mask);
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}
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// ... (ii) timer-linked.
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switch(HorizontalEvent(horizontal_counter_)) {
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case HorizontalEvent::CounterOverflow:
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horizontal_counter_ = 0;
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[[fallthrough]];
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case HorizontalEvent::Begin40Columns:
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if(vertical_screen_ && enable_display_) wide_screen_ = true;
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break;
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case HorizontalEvent::End40Columns:
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if(vertical_screen_ && enable_display_) wide_screen_ = false;
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break;
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case HorizontalEvent::Begin38Columns:
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if(vertical_screen_ && enable_display_) narrow_screen_ = true;
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break;
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case HorizontalEvent::End38Columns:
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if(vertical_screen_ && enable_display_) narrow_screen_ = false;
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video_shift_ = false;
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break;
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case HorizontalEvent::DMAWindowEnd: dma_window_ = false; break;
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case HorizontalEvent::EndRefresh: refresh_ = false; break;
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case HorizontalEvent::EndCharacterFetchWindow: character_window_ = false; break;
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case HorizontalEvent::BeginBlank: horizontal_blank_ = true; break;
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case HorizontalEvent::BeginSync: horizontal_sync_ = true; break;
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case HorizontalEvent::EndSync: horizontal_sync_ = false; break;
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case HorizontalEvent::LatchCharacterPosition: schedule<8>(DelayedEvent::Latch); break;
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case HorizontalEvent::IncrementFlashCounter: schedule<4>(DelayedEvent::Flash); break;
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case HorizontalEvent::EndOfScreen:
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schedule<8>(DelayedEvent::IncrementVerticalLine);
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next_vertical_counter_ = video_line_ == eos() ? 0 : ((vertical_counter_ + 1) & 511);
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horizontal_burst_ = true;
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break;
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case HorizontalEvent::EndExternalFetchWindow:
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external_fetch_ = false;
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increment_character_position_ = false;
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if(enable_display_) increment_video_counter_ = false;
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refresh_ = true;
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break;
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case HorizontalEvent::VerticalSubActive:
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if(bad_line()) {
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vertical_sub_active_ = true;
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} else if(!enable_display_) {
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vertical_sub_active_ = false;
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}
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break;
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case HorizontalEvent::IncrementVerticalSub:
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schedule<8>(DelayedEvent::IncrementVerticalSub);
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video_line_ = vertical_counter_;
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character_position_ = 0;
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if(video_line_ == eos()) {
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character_position_reload_ = 0;
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video_counter_reload_ = 0;
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}
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break;
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case HorizontalEvent::ScheduleCounterReset:
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schedule<1>(DelayedEvent::CounterReset);
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break;
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case HorizontalEvent::BeginExternalFetchClock:
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external_fetch_ = true;
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if(video_line_ == vs_start()) {
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vertical_sync_ = true;
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} else if(video_line_ == vs_stop()) {
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vertical_sync_ = false;
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}
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break;
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case HorizontalEvent::BeginAttributeFetch:
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dma_window_ = true;
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horizontal_burst_ = false; // Should be 1 cycle later, if the data sheet is completely accurate.
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// Though all other timings work on the assumption that it isn't.
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break;
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case HorizontalEvent::EndBlank:
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horizontal_blank_ = false;
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break;
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case HorizontalEvent::IncrementVideoCounter:
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increment_character_position_ = true;
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if(enable_display_) increment_video_counter_ = true;
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if(enable_display_ && vertical_sub_active_) {
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character_position_ = character_position_reload_;
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}
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video_counter_ = video_counter_reload_;
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break;
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case HorizontalEvent::BeginShiftRegister:
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if(enable_display_) {
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character_window_ = video_shift_ = true;
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}
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output_.reset();
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break;
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}
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// Test for raster interrupt.
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if(raster_interrupt_ == vertical_counter_) {
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if(!raster_interrupt_done_) {
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@ -435,155 +577,11 @@ public:
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}
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}
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}
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// Advance for the current period.
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time_in_state_ += period;
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//
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// Advance for current period, then check for...
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//
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horizontal_counter_ += period;
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// ... deferred events, and...
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if(delayed_events_) {
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delayed_events_ >>= period * DelayEventSize;
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if(delayed_events_ & uint64_t(DelayedEvent::Latch)) {
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if(char_pos_latch_ && vertical_sub_active_) {
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character_position_reload_ = character_position_;
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}
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char_pos_latch_ = vertical_sub_count_ == 6;
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if(char_pos_latch_ && enable_display_) {
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video_counter_reload_ = video_counter_;
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}
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}
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if(delayed_events_ & uint64_t(DelayedEvent::Flash)) {
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if(vertical_counter_ == 205) {
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++flash_count_;
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flash_mask_ = (flash_count_ & 0x10) ? 0xff : 0x00;
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}
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}
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if(delayed_events_ & uint64_t(DelayedEvent::IncrementVerticalLine)) {
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vertical_counter_ = next_vertical_counter_;
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bad_line2_ = bad_line();
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}
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if(delayed_events_ & uint64_t(DelayedEvent::IncrementVerticalSub)) {
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if(!video_line_) {
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vertical_sub_count_ = 7; // TODO: should be between cycle 0xc8 and 0xca?
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} else if(display_enable_ && vertical_sub_active_) {
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vertical_sub_count_ = (vertical_sub_count_ + 1) & 7;
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}
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}
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if(delayed_events_ & uint64_t(DelayedEvent::CounterReset)) {
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horizontal_counter_ = 0;
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}
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delayed_events_ &= ~uint64_t(DelayedEvent::Mask);
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}
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// ... timer-linked events.
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switch(HorizontalEvent(horizontal_counter_)) {
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case HorizontalEvent::CounterOverflow:
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horizontal_counter_ = 0;
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[[fallthrough]];
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case HorizontalEvent::Begin40Columns:
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if(vertical_screen_ && enable_display_) wide_screen_ = true;
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break;
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case HorizontalEvent::End40Columns:
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if(vertical_screen_ && enable_display_) wide_screen_ = false;
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break;
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case HorizontalEvent::Begin38Columns:
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if(vertical_screen_ && enable_display_) narrow_screen_ = true;
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break;
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case HorizontalEvent::End38Columns:
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if(vertical_screen_ && enable_display_) narrow_screen_ = false;
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video_shift_ = false;
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break;
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case HorizontalEvent::DMAWindowEnd: dma_window_ = false; break;
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case HorizontalEvent::EndRefresh: refresh_ = false; break;
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case HorizontalEvent::EndCharacterFetchWindow: character_window_ = false; break;
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case HorizontalEvent::BeginBlank: horizontal_blank_ = true; break;
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case HorizontalEvent::BeginSync: horizontal_sync_ = true; break;
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case HorizontalEvent::EndSync: horizontal_sync_ = false; break;
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case HorizontalEvent::LatchCharacterPosition: schedule<8>(DelayedEvent::Latch); break;
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case HorizontalEvent::IncrementFlashCounter: schedule<4>(DelayedEvent::Flash); break;
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case HorizontalEvent::EndOfScreen:
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schedule<8>(DelayedEvent::IncrementVerticalLine);
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next_vertical_counter_ = video_line_ == eos() ? 0 : ((vertical_counter_ + 1) & 511);
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horizontal_burst_ = true;
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break;
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case HorizontalEvent::EndExternalFetchWindow:
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external_fetch_ = false;
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increment_character_position_ = false;
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if(enable_display_) increment_video_counter_ = false;
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refresh_ = true;
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break;
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case HorizontalEvent::VerticalSubActive:
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if(bad_line()) {
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vertical_sub_active_ = true;
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} else if(!enable_display_) {
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vertical_sub_active_ = false;
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}
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break;
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case HorizontalEvent::IncrementVerticalSub:
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schedule<8>(DelayedEvent::IncrementVerticalSub);
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video_line_ = vertical_counter_;
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character_position_ = 0;
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if(video_line_ == eos()) {
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character_position_reload_ = 0;
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video_counter_reload_ = 0;
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}
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break;
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case HorizontalEvent::ScheduleCounterReset:
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schedule<1>(DelayedEvent::CounterReset);
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break;
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case HorizontalEvent::BeginExternalFetchClock:
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external_fetch_ = true;
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if(video_line_ == vs_start()) {
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vertical_sync_ = true;
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} else if(video_line_ == vs_stop()) {
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vertical_sync_ = false;
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}
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break;
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case HorizontalEvent::BeginAttributeFetch:
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dma_window_ = true;
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horizontal_burst_ = false; // Should be 1 cycle later, if the data sheet is completely accurate.
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// Though all other timings work on the assumption that it isn't.
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break;
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case HorizontalEvent::EndBlank:
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horizontal_blank_ = false;
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break;
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case HorizontalEvent::IncrementVideoCounter:
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increment_character_position_ = true;
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if(enable_display_) increment_video_counter_ = true;
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if(enable_display_ && vertical_sub_active_) {
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character_position_ = character_position_reload_;
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}
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video_counter_ = video_counter_reload_;
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break;
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case HorizontalEvent::BeginShiftRegister:
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if(enable_display_) {
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character_window_ = video_shift_ = true;
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}
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output_.reset();
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break;
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}
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delayed_events_ >>= period * DelayEventSize;
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ticks_remaining -= period;
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}
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}
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