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It's inaccurrate to call this _the_ shifter. So don't.

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This commit is contained in:
Thomas Harte 2019-12-27 19:03:10 -05:00
parent ec9357e080
commit 5fa8e046d8
2 changed files with 19 additions and 19 deletions
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32
Machines/Atari/ST/Video.cpp
View File

@ -107,7 +107,7 @@ const int hsync_end = CYCLE(8); // Cycles before end of line when hsync ends.
Video::Video() :
deferrer_([=] (HalfCycles duration) { advance(duration); }),
crt_(1024, 1, Outputs::Display::Type::PAL50, Outputs::Display::InputDataType::Red4Green4Blue4),
shifter_(crt_, palette_) {
video_stream_(crt_, palette_) {
// Show a total of 260 lines; a little short for PAL but a compromise between that and the ST's
// usual output height of 200 lines.
@ -201,11 +201,11 @@ void Video::advance(HalfCycles duration) {
// inside the shifter on the temporary register values.
if(horizontal_.sync || vertical_.sync) {
shifter_.output_sync(run_length);
video_stream_.output_sync(run_length);
} else if(horizontal_.blank || vertical_.blank) {
shifter_.output_blank(run_length);
video_stream_.output_blank(run_length);
} else if(!load_) {
shifter_.output_border(run_length, output_bpp_);
video_stream_.output_border(run_length, output_bpp_);
} else {
const int since_load = x_ - load_base_;
@ -222,12 +222,12 @@ void Video::advance(HalfCycles duration) {
// was reloaded by the fetch depends on the FIFO.
if(start_column == end_column) {
shifter_.output_pixels(run_length, output_bpp_);
video_stream_.output_pixels(run_length, output_bpp_);
} else {
// Continue the current column if partway across.
if(since_load&7) {
// If at least one column boundary is crossed, complete this column.
shifter_.output_pixels(8 - (since_load & 7), output_bpp_);
video_stream_.output_pixels(8 - (since_load & 7), output_bpp_);
++start_column; // This starts a new column, so latch a new word.
push_latched_data();
}
@ -235,13 +235,13 @@ void Video::advance(HalfCycles duration) {
// Run for all columns that have their starts in this time period.
int complete_columns = end_column - start_column;
while(complete_columns--) {
shifter_.output_pixels(8, output_bpp_);
video_stream_.output_pixels(8, output_bpp_);
push_latched_data();
}
// Output the start of the next column, if necessary.
if((since_load + run_length) & 7) {
shifter_.output_pixels((since_load + run_length) & 7, output_bpp_);
video_stream_.output_pixels((since_load + run_length) & 7, output_bpp_);
}
}
}
@ -331,7 +331,7 @@ void Video::push_latched_data() {
data_latch_read_position_ = (data_latch_read_position_ + 1) & 127;
if(!(data_latch_read_position_ & 3)) {
shifter_.load(
video_stream_.load(
(uint64_t(data_latch_[(data_latch_read_position_ - 4) & 127]) << 48) |
(uint64_t(data_latch_[(data_latch_read_position_ - 3) & 127]) << 32) |
(uint64_t(data_latch_[(data_latch_read_position_ - 2) & 127]) << 16) |
@ -489,7 +489,7 @@ void Video::update_output_mode() {
// MARK: - The shifter
void Video::Shifter::flush_output(OutputMode next_mode) {
void Video::VideoStream::flush_output(OutputMode next_mode) {
switch(output_mode_) {
case OutputMode::Sync: crt_.output_sync(duration_); break;
case OutputMode::Blank: crt_.output_blank(duration_); break;
@ -513,7 +513,7 @@ void Video::Shifter::flush_output(OutputMode next_mode) {
output_mode_ = next_mode;
}
void Video::Shifter::output_colour_burst(int duration) {
void Video::VideoStream::output_colour_burst(int duration) {
// More hackery afoot here; if and when duration_ crosses a threshold of 40,
// output 40 cycles of colour burst and then redirect to blank.
if(output_mode_ != OutputMode::ColourBurst) {
@ -528,7 +528,7 @@ void Video::Shifter::output_colour_burst(int duration) {
}
}
void Video::Shifter::output_blank(int duration) {
void Video::VideoStream::output_blank(int duration) {
if(output_mode_ != OutputMode::Blank) {
// Bit of a hack: if this is a transition from sync or we're really in
// colour burst, divert into that.
@ -541,14 +541,14 @@ void Video::Shifter::output_blank(int duration) {
duration_ += duration;
}
void Video::Shifter::output_sync(int duration) {
void Video::VideoStream::output_sync(int duration) {
if(output_mode_ != OutputMode::Sync) {
flush_output(OutputMode::Sync);
}
duration_ += duration;
}
void Video::Shifter::output_border(int duration, OutputBpp bpp) {
void Video::VideoStream::output_border(int duration, OutputBpp bpp) {
// If there's still anything in the shifter, redirect this to an output_pixels call.
if(output_shifter_) {
// This doesn't take an opinion on how much of the shifter remains populated;
@ -569,7 +569,7 @@ void Video::Shifter::output_border(int duration, OutputBpp bpp) {
duration_ += duration;
}
void Video::Shifter::output_pixels(int duration, OutputBpp bpp) {
void Video::VideoStream::output_pixels(int duration, OutputBpp bpp) {
// If the shifter is empty and there's no pixel buffer at present,
// redirect this to an output_level call. Otherwise, do a quick
// memset-type fill, since the special case has been detected anyway.
@ -680,7 +680,7 @@ void Video::Shifter::output_pixels(int duration, OutputBpp bpp) {
}
}
void Video::Shifter::load(uint64_t value) {
void Video::VideoStream::load(uint64_t value) {
output_shifter_ = value;
}

6
Machines/Atari/ST/Video.hpp
View File

@ -166,9 +166,9 @@ class Video {
void reset_fifo();
class Shifter {
class VideoStream {
public:
Shifter(Outputs::CRT::CRT &crt, uint16_t *palette) : crt_(crt), palette_(palette) {}
VideoStream(Outputs::CRT::CRT &crt, uint16_t *palette) : crt_(crt), palette_(palette) {}
void output_blank(int duration);
void output_sync(int duration);
void output_border(int duration, OutputBpp bpp);
@ -196,7 +196,7 @@ class Video {
Outputs::CRT::CRT &crt_;
uint16_t *palette_ = nullptr;
} shifter_;
} video_stream_;
/// Contains copies of the various observeable fields, after the relevant propagation delay.
struct PublicState {