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Attempts to switch to correct video state machine.

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Some glitches remain to be ironed out.
This commit is contained in:
Thomas Harte 2019-11-05 23:02:25 -05:00
parent 6c75c60149
commit 41f3c29e30
3 changed files with 334 additions and 153 deletions
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4
Machines/AtariST/AtariST.cpp
View File

@ -64,8 +64,8 @@ class ConcreteMachine:
set_clock_rate(CLOCK_RATE);
speaker_.set_input_rate(CLOCK_RATE / 4);
ram_.resize(512 * 512);
video_->set_ram(ram_.data());
ram_.resize(512 * 512); // i.e. 512kb
video_->set_ram(ram_.data(), ram_.size());
Memory::Fuzz(ram_);
std::vector<ROMMachine::ROM> rom_descriptions = {

440
Machines/AtariST/Video.cpp
View File

@ -16,35 +16,54 @@ using namespace Atari::ST;
namespace {
struct ModeParams {
const int lines_per_frame;
const int first_video_line;
const int final_video_line;
const int line_length;
const int end_of_blank;
const int start_of_display_enable;
const int end_of_display_enable;
const int start_of_output;
const int end_of_output;
const int start_of_blank;
const int start_of_hsync;
const int end_of_hsync;
} modes[3] = {
{313, 56, 256, 1024, 64, 116, 116+640, 116+48, 116+48+640, 904, 928, 1008 },
{},
{}
/*!
Defines the line counts at which mode-specific events will occur:
vertical enable being set and being reset, and the line on which
the frame will end.
*/
struct VerticalParams {
const int set_enable;
const int reset_enable;
const int height;
} vertical_params[3] = {
{63, 264, 313}, // 47 rather than 63 on early machines.
{34, 234, 263},
{1, 401, 500} // 72 Hz mode: who knows?
};
const ModeParams &mode_params_for_mode() {
// TODO: rest of potential combinations, and accept mode as a paramter.
return modes[0];
/// @returns The correct @c VerticalParams for output at @c frequency.
const VerticalParams &vertical_parameters(FieldFrequency frequency) {
return vertical_params[int(frequency)];
}
/*!
Defines the horizontal counts at which mode-specific events will occur:
horizontal enable being set and being reset, blank being set and reset, and the
intended length of this ine.
The caller should:
* latch line length at cycle 54 (TODO: also for 72Hz mode?);
* at (line length - 50), start sync and reset enable (usually for the second time);
* at (line length - 10), disable sync.
*/
struct HorizontalParams {
const int set_enable;
const int reset_enable;
const int set_blank;
const int reset_blank;
const int length;
} modes[3] = {
{56*2, 376*2, 450*2, 28*2, 512*2},
{52*2, 372*2, 450*2, 24*2, 508*2},
{4*2, 164*2, 184*2, 2*2, 224*2}
};
const HorizontalParams &horizontal_parameters(FieldFrequency frequency) {
return modes[int(frequency)];
}
}
@ -53,7 +72,7 @@ Video::Video() :
crt_(1024, 1, Outputs::Display::Type::PAL50, Outputs::Display::InputDataType::Red4Green4Blue4) {
}
void Video::set_ram(uint16_t *ram) {
void Video::set_ram(uint16_t *ram, size_t size) {
ram_ = ram;
}
@ -62,98 +81,216 @@ void Video::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
}
void Video::run_for(HalfCycles duration) {
const auto horizontal_timings = horizontal_parameters(field_frequency_);
const auto vertical_timings = vertical_parameters(field_frequency_);
int integer_duration = int(duration.as_integral());
const auto mode_params = mode_params_for_mode();
#define Period(lower, upper, type) \
if(x >= lower && x < upper) { \
const auto target = std::min(upper, final_x); \
type(target - x); \
x = target; \
}
// TODO: the below is **way off**. The real hardware does what you'd expect with ongoing state and
// exact equality tests. Fixes to come.
while(integer_duration) {
const int final_x = std::min(x + integer_duration, mode_params.line_length);
integer_duration -= (final_x - x);
// Seed next event to end of line.
int next_event = line_length_;
if(y >= mode_params.first_video_line && y < mode_params.final_video_line) {
// TODO: Prior to output: collect all necessary data, obeying start_of_display_enable and end_of_display_enable.
// Check the explicitly-placed events.
if(horizontal_timings.reset_blank > x) next_event = std::min(next_event, horizontal_timings.reset_blank);
if(horizontal_timings.set_blank > x) next_event = std::min(next_event, horizontal_timings.set_blank);
if(horizontal_timings.reset_enable > x) next_event = std::min(next_event, horizontal_timings.reset_enable);
if(horizontal_timings.set_enable > x) next_event = std::min(next_event, horizontal_timings.set_enable);
Period(0, mode_params.end_of_blank, crt_.output_blank);
Period(mode_params.end_of_blank, mode_params.start_of_output, output_border);
// Check for events that are relative to existing latched state.
if(line_length_ - 50 > x) next_event = std::min(next_event, line_length_ - 50);
if(line_length_ - 10 > x) next_event = std::min(next_event, line_length_ - 10);
if(x >= mode_params.start_of_output && x < mode_params.end_of_output) {
if(x == mode_params.start_of_output) {
// TODO: resolutions other than 320.
pixel_pointer_ = reinterpret_cast<uint16_t *>(crt_.begin_data(320));
}
// Determine current output mode and number of cycles to output for.
const int run_length = std::min(integer_duration, next_event - x);
const auto target = std::min(mode_params.end_of_output, final_x);
while(x < target) {
if(!(x&31) && pixel_pointer_) {
// TODO: RAM sizes other than 512kb.
uint16_t source[4] = {
ram_[(current_address_ + 0) & 262143],
ram_[(current_address_ + 1) & 262143],
ram_[(current_address_ + 2) & 262143],
ram_[(current_address_ + 3) & 262143],
};
current_address_ += 4;
enum class OutputMode {
Sync, Blank, Border, Pixels
} output_mode;
for(int c = 0; c < 16; ++c) {
*pixel_pointer_ = palette_[
((source[3] >> 12) & 0x8) |
((source[2] >> 13) & 0x4) |
((source[1] >> 14) & 0x2) |
((source[0] >> 15) & 0x1)
];
source[0] <<= 1;
source[1] <<= 1;
source[2] <<= 1;
source[3] <<= 1;
++pixel_pointer_;
}
}
++x;
}
if(x == mode_params.end_of_output) {
crt_.output_data(mode_params.end_of_output - mode_params.start_of_output, 320);
pixel_pointer_ = nullptr;
}
}
Period(mode_params.end_of_output, mode_params.start_of_blank, output_border);
Period(mode_params.start_of_blank, mode_params.start_of_hsync, crt_.output_blank);
Period(mode_params.start_of_hsync, mode_params.end_of_hsync, crt_.output_sync);
Period(mode_params.end_of_hsync, mode_params.line_length, crt_.output_blank);
if(horizontal_.sync || vertical_.sync) {
// Output sync.
output_mode = OutputMode::Sync;
} else if(horizontal_.blank || vertical_.blank) {
// Output blank.
output_mode = OutputMode::Blank;
} else if(!vertical_.enable) {
// There can be no pixels this line, just draw border.
output_mode = OutputMode::Border;
} else {
// Hard code the first three lines as vertical sync.
if(y < 3) {
Period(0, mode_params.start_of_hsync, crt_.output_sync);
Period(mode_params.start_of_hsync, mode_params.end_of_hsync, crt_.output_blank);
Period(mode_params.end_of_hsync, mode_params.line_length, crt_.output_sync);
} else {
Period(0, mode_params.end_of_blank, crt_.output_blank);
Period(mode_params.end_of_blank, mode_params.start_of_blank, output_border);
Period(mode_params.start_of_blank, mode_params.start_of_hsync, crt_.output_blank);
Period(mode_params.start_of_hsync, mode_params.end_of_hsync, crt_.output_sync);
Period(mode_params.end_of_hsync, mode_params.line_length, crt_.output_blank);
}
output_mode = horizontal_.enable ? OutputMode::Pixels : OutputMode::Border;
}
if(x == mode_params.line_length) {
// Flush any lingering pixels.
if(
(pixel_buffer_.output_bpp != output_bpp_) || // Buffer is now of wrong density.
(output_mode != OutputMode::Pixels && pixel_buffer_.pixels_output)) { // Buffering has stopped for now.
pixel_buffer_.flush(crt_);
}
switch(output_mode) {
case OutputMode::Sync: crt_.output_sync(run_length); break;
case OutputMode::Blank:
data_latch_position_ = 0;
crt_.output_blank(run_length);
break;
case OutputMode::Border: {
if(!output_shifter) {
output_border(run_length);
} else {
if(run_length < 32) {
shift_out(run_length);
} else {
shift_out(32);
output_border(run_length - 32);
}
}
} break;
default:
// There will be pixels this line, subject to the shifter pipeline.
// Divide into 8-[half-]cycle windows; at the start of each window fetch a word,
// and during the rest of the window, shift out.
int start_column = x >> 3;
const int end_column = (x + run_length) >> 3;
if(start_column == end_column) {
shift_out(run_length);
} else {
// Continue the current column if partway across.
if(x&7) {
// If at least one column boundary is crossed, complete this column.
// Otherwise the run_length is clearly less than 8 and within this column,
// so go for the entirety of it.
shift_out(8 - (x & 7));
++start_column;
}
// Run for all columns that have their starts in this time period.
int complete_columns = end_column - start_column;
while(complete_columns--) {
latch_word();
shift_out(8);
}
// Output the start of the next column, if necessary.
if(start_column != end_column && (x + run_length) & 7) {
latch_word();
shift_out((x + run_length) & 7);
}
}
break;
}
// Check for whether line length should have been latched during this run.
if(x <= 54 && (x + run_length) > 54) line_length_ = horizontal_timings.length;
// Apply the next event.
x += run_length;
integer_duration -= run_length;
if(horizontal_timings.reset_blank == x) horizontal_.blank = false;
if(horizontal_timings.set_blank == x) horizontal_.blank = true;
if(horizontal_timings.reset_enable == x) horizontal_.enable = false;
if(horizontal_timings.set_enable == x) horizontal_.enable = true;
if(line_length_ - 50 == x) horizontal_.sync = true;
if(line_length_ - 10 == x) horizontal_.sync = false;
// Check whether the terminating event was end-of-line; if so then advance
// the vertical bits of state.
if(x == line_length_) {
x = 0;
y = (y + 1) % mode_params.lines_per_frame;
if(!y)
++y;
// Use vertical_parameters to get parameters for the current output frequency.
if(y == vertical_timings.set_enable) {
vertical_.enable = true;
} else if(y == vertical_timings.reset_enable) {
vertical_.enable = false;
} else if(y == vertical_timings.height) {
y = 0;
vertical_.sync = true;
current_address_ = base_address_ >> 1;
} else if(y == 3) {
vertical_.sync = false;
}
}
}
}
#undef Period
void Video::latch_word() {
data_latch_[data_latch_position_] = ram_[current_address_ & 262143];
++current_address_;
++data_latch_position_;
if(data_latch_position_ == 4) {
data_latch_position_ = 0;
output_shifter =
(uint64_t(data_latch_[0]) << 48) |
(uint64_t(data_latch_[1]) << 32) |
(uint64_t(data_latch_[2]) << 16) |
uint64_t(data_latch_[3]);
}
}
void Video::shift_out(int length) {
if(!pixel_buffer_.pixel_pointer) pixel_buffer_.allocate(crt_);
pixel_buffer_.cycles_output += length;
switch(output_bpp_) {
case OutputBpp::One: {
int pixels = length << 1;
pixel_buffer_.pixels_output += pixels;
if(pixel_buffer_.pixel_pointer) {
while(pixels--) {
*pixel_buffer_.pixel_pointer = ((output_shifter >> 63) & 1) * 0xffff;
output_shifter <<= 1;
++pixel_buffer_.pixel_pointer;
}
} else {
output_shifter <<= pixels;
}
} break;
case OutputBpp::Two:
pixel_buffer_.pixels_output += length;
if(pixel_buffer_.pixel_pointer) {
while(length--) {
*pixel_buffer_.pixel_pointer = palette_[
((output_shifter >> 63) & 1) |
((output_shifter >> 46) & 2)
];
output_shifter = (output_shifter << 1) & 0xefff;
++pixel_buffer_.pixel_pointer;
}
} else {
while(length--) {
output_shifter = (output_shifter << 1) & 0xefff;
}
}
break;
default:
case OutputBpp::Four:
pixel_buffer_.pixels_output += length >> 1;
if(pixel_buffer_.pixel_pointer) {
while(length) {
*pixel_buffer_.pixel_pointer = palette_[
((output_shifter >> 63) & 1) |
((output_shifter >> 46) & 2) |
((output_shifter >> 29) & 4) |
((output_shifter >> 12) & 8)
];
output_shifter = (output_shifter << 1) & 0xeeee;
++pixel_buffer_.pixel_pointer;
length -= 2;
}
} else {
while(length) {
output_shifter = (output_shifter << 1) & 0xeeee;
length -= 2;
}
}
break;
}
// Check for buffer being full. Buffers are allocated as 328 pixels, and this method is
// never called for more than 8 pixels, so there's no chance of overrun.
if(pixel_buffer_.pixels_output >= 320) pixel_buffer_.flush(crt_);
}
void Video::output_border(int duration) {
@ -163,61 +300,41 @@ void Video::output_border(int duration) {
}
bool Video::hsync() {
const auto mode_params = mode_params_for_mode();
return x >= mode_params.start_of_hsync && x < mode_params.end_of_hsync;
return horizontal_.sync;
}
bool Video::vsync() {
return y < 3;
return vertical_.sync;
}
bool Video::display_enabled() {
const auto mode_params = mode_params_for_mode();
return y >= mode_params.first_video_line && y < mode_params.final_video_line && x >= mode_params.start_of_display_enable && x < mode_params.end_of_display_enable;
return horizontal_.enable && vertical_.enable;
}
HalfCycles Video::get_next_sequence_point() {
// The next hsync transition will occur either this line or the next.
const auto mode_params = mode_params_for_mode();
HalfCycles cycles_until_hsync;
if(x < mode_params.start_of_hsync) {
cycles_until_hsync = HalfCycles(mode_params.start_of_hsync - x);
} else if(x < mode_params.end_of_hsync) {
cycles_until_hsync = HalfCycles(mode_params.end_of_hsync - x);
} else {
cycles_until_hsync = HalfCycles(mode_params.start_of_hsync + mode_params.line_length - x);
}
// The next sequence point will be whenever display_enabled, vsync or hsync next changes.
// The next vsync transition depends purely on the current y.
HalfCycles cycles_until_vsync;
if(y < 3) {
cycles_until_vsync = HalfCycles(mode_params.line_length - x + (2 - y)*mode_params.line_length);
} else {
cycles_until_vsync = HalfCycles(mode_params.line_length - x + (mode_params.lines_per_frame - 1 - y)*mode_params.line_length);
}
// The next display enable transition will occur only in the visible area.
HalfCycles cycles_until_display_enable;
if(display_enabled()) {
cycles_until_display_enable = HalfCycles(mode_params.end_of_display_enable - x);
} else {
const auto horizontal_cycles = mode_params.start_of_display_enable - x;
int vertical_lines = 0;
if(y < mode_params.first_video_line) {
vertical_lines = mode_params.first_video_line - y;
} else if(y >= mode_params.final_video_line ) {
vertical_lines = mode_params.first_video_line + mode_params.lines_per_frame - y;
// If this is a vertically-enabled line, and right now is either before graphics display,
// or during it, then it's display enabled that will change next.
const auto horizontal_timings = horizontal_parameters(field_frequency_);
if(vertical_.enable) {
if(x < horizontal_timings.set_enable) {
return HalfCycles(horizontal_timings.set_enable - x);
} else if(x < horizontal_timings.reset_enable) {
return HalfCycles(horizontal_timings.reset_enable - x);
}
if(horizontal_cycles < 0) ++vertical_lines;
cycles_until_display_enable = HalfCycles(horizontal_cycles + vertical_lines * mode_params.line_length);
}
// Determine the minimum of the three
if(cycles_until_hsync < cycles_until_vsync && cycles_until_hsync < cycles_until_display_enable) {
return cycles_until_hsync;
} else {
return (cycles_until_vsync < cycles_until_display_enable) ? cycles_until_vsync : cycles_until_display_enable;
}
// Otherwise, if this is before or during horizontal sync then that's the next event.
if(x < line_length_ - 50) return HalfCycles(line_length_ - 50 - x);
else if(x < line_length_ - 10) return HalfCycles(line_length_ - 10 - x);
// Okay, then, it depends on the next line. If the next line is the start or end of vertical sync,
// it's that. Otherwise it's the beginning of display enable on the next line.
const auto vertical_timings = horizontal_parameters(field_frequency_);
if(y+1 == vertical_timings.length || y+1 == 3) return HalfCycles(line_length_ - x);
return HalfCycles(line_length_ + horizontal_timings.set_enable - x);
}
// MARK: - IO dispatch
@ -233,6 +350,7 @@ uint16_t Video::read(int address) {
case 0x02: return uint16_t(0xff00 | (current_address_ >> 16));
case 0x03: return uint16_t(0xff00 | (current_address_ >> 8));
case 0x04: return uint16_t(0xff00 | (current_address_));
case 0x05: return sync_mode_ | 0xfcff;
case 0x30: return video_mode_ | 0xfcff;
}
return 0xff;
@ -248,8 +366,15 @@ void Video::write(int address, uint16_t value) {
case 0x00: base_address_ = (base_address_ & 0x00ffff) | ((value & 0xff) << 16); break;
case 0x01: base_address_ = (base_address_ & 0xff00ff) | ((value & 0xff) << 8); break;
// Mode.
case 0x30: video_mode_ = value; break;
// Sync mode and pixel mode.
case 0x05:
sync_mode_ = value;
update_output_mode();
break;
case 0x30:
video_mode_ = value;
update_output_mode();
break;
// Palette.
case 0x20: case 0x21: case 0x22: case 0x23:
@ -262,3 +387,20 @@ void Video::write(int address, uint16_t value) {
} break;
}
}
void Video::update_output_mode() {
// If this is black and white mode, that's that.
switch((video_mode_ >> 8) & 3) {
default:
case 0: output_bpp_ = OutputBpp::Four; break;
case 1: output_bpp_ = OutputBpp::Two; break;
// 1bpp mode ignores the otherwise-programmed frequency.
case 2:
output_bpp_ = OutputBpp::One;
field_frequency_ = FieldFrequency::SeventyTwo;
return;
}
field_frequency_ = (sync_mode_ & 0x200) ? FieldFrequency::Fifty : FieldFrequency::Sixty;
}

43
Machines/AtariST/Video.hpp
View File

@ -15,6 +15,10 @@
namespace Atari {
namespace ST {
enum class FieldFrequency {
Fifty = 0, Sixty = 1, SeventyTwo = 2
};
class Video {
public:
Video();
@ -39,7 +43,7 @@ class Video {
bool vsync();
bool display_enabled();
void set_ram(uint16_t *);
void set_ram(uint16_t *, size_t size);
uint16_t read(int address);
void write(int address, uint16_t value);
@ -53,12 +57,47 @@ class Video {
uint16_t *ram_;
uint16_t line_buffer_[256];
uint16_t *pixel_pointer_;
int x = 0, y = 0;
void output_border(int duration);
uint16_t video_mode_ = 0;
uint16_t sync_mode_ = 0;
FieldFrequency field_frequency_ = FieldFrequency::Fifty;
enum class OutputBpp {
One, Two, Four
} output_bpp_;
void update_output_mode();
struct State {
bool enable = false;
bool blank = false;
bool sync = false;
} horizontal_, vertical_;
int line_length_ = 512;
int data_latch_position_ = 0;
uint16_t data_latch_[4];
uint64_t output_shifter;
void shift_out(int length);
void latch_word();
struct PixelBufferState {
uint16_t *pixel_pointer;
int pixels_output = 0;
int cycles_output = 0;
OutputBpp output_bpp;
void flush(Outputs::CRT::CRT &crt) {
if(cycles_output) crt.output_data(cycles_output, size_t(pixels_output));
pixels_output = cycles_output = 0;
pixel_pointer = nullptr;
}
void allocate(Outputs::CRT::CRT &crt) {
flush(crt);
pixel_pointer = reinterpret_cast<uint16_t *>(crt.begin_data(328));
}
} pixel_buffer_;
};
}