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Pulls out address reload position as a separate constant.

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Thomas Harte 2019-12-28 10:36:50 -05:00
parent a9d1f5d925
commit f7825dd2a2
1 changed files with 23 additions and 19 deletions
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42
Machines/Atari/ST/Video.cpp
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@ -94,10 +94,11 @@ struct Checker {
} checker; } checker;
#endif #endif
const int de_delay_period = CYCLE(28); // Number of half cycles after DE that observed DE changes. const int de_delay_period = CYCLE(28); // Number of half cycles after DE that observed DE changes.
const int vsync_x_position = CYCLE(54); // Horizontal cycle on which vertical sync changes happen. const int vsync_x_position = CYCLE(54); // Horizontal cycle on which vertical sync changes happen.
const int hsync_start = CYCLE(48); // Cycles before end of line when hsync starts. const int address_reload_x_position = CYCLE(54); // Horizontal cycle on which the base address is reloaded.
const int hsync_end = CYCLE(8); // Cycles before end of line when hsync ends. const int hsync_start = CYCLE(48); // Cycles before end of line when hsync starts.
const int hsync_end = CYCLE(8); // Cycles before end of line when hsync ends.
// "VSYNC starts 104 cycles after the start of the previous line's HSYNC, so that's 4 cycles before DE would be activated. "; // "VSYNC starts 104 cycles after the start of the previous line's HSYNC, so that's 4 cycles before DE would be activated. ";
// hsync is at -50, so that's +54, or thereabouts. // hsync is at -50, so that's +54, or thereabouts.
@ -246,10 +247,21 @@ void Video::advance(HalfCycles duration) {
} }
} }
// Check for address reload; this timing is _highly_ speculative on my part. // Check for address reload; this timing is _highly_ speculative on my part. I originally had it at frame end,
if(y_ == vertical_timings.height - 3 && x_ <= vsync_x_position && (x_ + run_length) > vsync_x_position) { // then Enchanted Woods seemed to be doing its things three lines too late, so I moved it forward a little.
// Which didn't solve the problem, so I guess that title's logic isn't triggered on address reload, but it makes
// sense to keep it out separate and I've no better intel about its actual positioning.
if(y_ == vertical_timings.height - 3 && x_ <= address_reload_x_position && (x_ + run_length) > address_reload_x_position) {
current_address_ = base_address_ >> 1; current_address_ = base_address_ >> 1;
reset_fifo(); // TODO: remove this, probably, once otherwise stable? reset_fifo(); // TODO: remove this, probably, once otherwise stable?
// Consider a shout out to the range observer.
if(previous_base_address_ != base_address_) {
previous_base_address_ = base_address_;
if(range_observer_) {
range_observer_->video_did_change_access_range(this);
}
}
} }
// Check for whether line length should have been latched during this run. // Check for whether line length should have been latched during this run.
@ -270,20 +282,12 @@ void Video::advance(HalfCycles duration) {
next_vertical_.enable = true; next_vertical_.enable = true;
} else if(y_ == vertical_timings.reset_enable) { } else if(y_ == vertical_timings.reset_enable) {
next_vertical_.enable = false; next_vertical_.enable = false;
} else if(next_y_ == vertical_timings.height - 1) {
next_vertical_.sync_schedule = VerticalState::SyncSchedule::Begin;
} else if(next_y_ == vertical_timings.height) { } else if(next_y_ == vertical_timings.height) {
next_y_ = 0; next_y_ = 0;
} else if(y_ == 0) { } else if(next_y_ == 2) {
next_vertical_.sync_schedule = VerticalState::SyncSchedule::Begin;
} else if(y_ == 3) {
next_vertical_.sync_schedule = VerticalState::SyncSchedule::End; next_vertical_.sync_schedule = VerticalState::SyncSchedule::End;
// Consider a shout out to the range observer.
if(previous_base_address_ != base_address_) {
previous_base_address_ = base_address_;
if(range_observer_) {
range_observer_->video_did_change_access_range(this);
}
}
} }
} }
@ -490,8 +494,8 @@ void Video::update_output_mode() {
video_stream_.set_bpp(output_bpp_); video_stream_.set_bpp(output_bpp_);
} }
// const int freqs[] = {50, 60, 72}; const int freqs[] = {50, 60, 72};
// printf("%d, %d -> %d [%d %d]\n", x_ / 2, y_, freqs[int(field_frequency_)], horizontal_.enable, vertical_.enable); printf("%d, %d -> %d [%d %d]\n", x_ / 2, y_, freqs[int(field_frequency_)], horizontal_.enable, vertical_.enable);
} }
// MARK: - The shifter // MARK: - The shifter