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Track basic frame events.

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This commit is contained in:
Thomas Harte 2024-12-11 21:54:03 -05:00
parent 0eab6146fc
commit a487619578
1 changed files with 63 additions and 37 deletions
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100
Machines/Commodore/Plus4/Video.hpp
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@ -82,8 +82,10 @@ public:
auto ticks_remaining = cycles.as<int>() * 8;
while(ticks_remaining) {
//
// Test vertical first; this will catch both any programmed change that has occurred outside
// of the loop and any change to the vertical counter that occurs during the horizontal runs.
//
const auto attribute_fetch_start = []{};
switch(vertical_counter_) {
case 261: // End of screen NTSC. [and hence 0: Attribute fetch start].
@ -115,29 +117,15 @@ public:
case 204: // Vertical screen window stop (25 lines).
break;
case 226: // NTSC vertical blank start.
break;
case 226: if(is_ntsc_) vertical_blank_ = true; break; // NTSC vertical blank start.
case 229: if(is_ntsc_) vertical_sync_ = true; break; // NTSC vsync start.
case 232: if(is_ntsc_) vertical_sync_ = false; break; // NTSC vsync end.
case 244: if(is_ntsc_) vertical_blank_ = false; break; // NTSC vertical blank end.
case 229: // NTSC vsync start.
break;
case 232: // NTSC vsync end.
break;
case 244: // NTSC vertical blank end.
break;
case 251: // PAL vertical blank start.
break;
case 254: // PAL vsync start.
break;
case 257: // PAL vsync end.
break;
case 269: // PAL vertical blank end.
break;
case 251: if(!is_ntsc_) vertical_blank_ = true; break; // PAL vertical blank start.
case 254: if(!is_ntsc_) vertical_sync_ = true; break; // PAL vsync start.
case 257: if(!is_ntsc_) vertical_sync_ = false; break; // PAL vsync end.
case 269: if(!is_ntsc_) vertical_blank_ = false; break; // PAL vertical blank end.
}
const auto next = Numeric::upper_bound<
@ -145,8 +133,36 @@ public:
>(horizontal_counter_);
const auto period = std::min(next - horizontal_counter_, ticks_remaining);
// printf("From %d next is %d\n", horizontal_counter_, next);
//
// TODO: output.
//
OutputState state;
if(vertical_sync_ || horizontal_sync_) {
state = OutputState::Sync;
} else if(vertical_blank_ || horizontal_blank_) {
state = horizontal_burst_ ? OutputState::Burst : OutputState::Blank;
} else {
state = OutputState::Border;
// TODO: pixels when?
}
if(state != output_state_) {
switch(output_state_) {
case OutputState::Blank: crt_.output_blank(time_in_state_); break;
case OutputState::Sync: crt_.output_sync(time_in_state_); break;
case OutputState::Burst: crt_.output_default_colour_burst(time_in_state_); break;
case OutputState::Border: crt_.output_level<uint16_t>(time_in_state_, 0x8080); break;
}
time_in_state_ = 0;
}
output_state_ = state;
time_in_state_ += period;
//
// Advance for current period.
//
horizontal_counter_ += period;
ticks_remaining -= period;
switch(horizontal_counter_) {
@ -177,31 +193,24 @@ public:
case 336: // Increment blink, increment refresh end.
break;
case 344: // Horizontal blanking start.
break;
case 358: // Horizontal sync start.
break;
case 376: // Increment vertical line.
++vertical_counter_;
break;
case 384: // Burst start, end of screen — clear vertical line, vertical sub and character reload registers.
horizontal_burst_ = true;
// TODO: rest.
break;
case 390: // Horizontal sync end.
break;
case 344: horizontal_blank_ = true; break; // Horizontal blanking start.
case 358: horizontal_sync_ = true; break; // Horizontal sync start.
case 390: horizontal_sync_ = false; break; // Horizontal sync end.
case 408: horizontal_burst_ = false; break; // Burst end.
case 416: horizontal_blank_ = false; break; // Horizontal blanking end.
case 400: // External fetch window start.
break;
case 408: // Burst end.
break;
case 416: // Horizontal blanking end.
break;
case 424: // Increment character position reload.
break;
@ -232,6 +241,7 @@ public:
private:
Outputs::CRT::CRT crt_;
// Programmable values.
bool extended_colour_mode_ = false;
bool bitmap_mode_ = false;
bool display_enable_ = false;
@ -250,8 +260,24 @@ private:
uint16_t character_generator_address_ = 0;
uint16_t screen_memory_address_ = 0;
// Field position.
int horizontal_counter_ = 0;
int vertical_counter_ = 0;
// Running state.
bool vertical_blank_ = false;
bool vertical_sync_ = false;
bool horizontal_blank_ = false;
bool horizontal_sync_ = false;
bool horizontal_burst_ = false;
enum class OutputState {
Blank,
Sync,
Burst,
Border,
} output_state_ = OutputState::Blank;
int time_in_state_ = 0;
};
}