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Introduce some vertical metrics.

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This commit is contained in:
Thomas Harte 2024-01-08 21:49:24 -05:00
parent 8290220657
commit f1453d9363
1 changed files with 38 additions and 8 deletions
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46
Components/6845/CRTC6845.hpp
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@ -103,13 +103,35 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
}
void set_register(uint8_t value) {
static constexpr bool is_ega = is_egavga(personality);
switch(selected_register_) {
case 0: layout_.horizontal.total = value; break;
case 1: layout_.horizontal.displayed = value; break;
case 2: layout_.horizontal.start_blank = value; break;
case 3:
if constexpr (is_ega) {
} else {
layout_.horizontal.sync_width = value & 0xf;
layout_.vertical.sync_lines = value >> 4;
// TODO: vertical sync lines:
// "(0 means 16 on some CRTC. Not present on all CRTCs, fixed to 16 lines on these)"
}
break;
case 4:
if constexpr (is_ega) {
} else {
layout_.vertical.total = value & 0x7f;
}
break;
case 5:
layout_.vertical.adjust = value & 0x1f;
break;
case 6:
layout_.vertical.displayed = value & 0x7f;
break;
}
static constexpr bool is_ega = is_egavga(personality);
static constexpr uint8_t masks[] = {
0xff, // Horizontal total.
0xff, // Horizontal display end.
@ -187,12 +209,12 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
switch(personality) {
case Personality::HD6845S:
case Personality::UM6845R:
bus_state_.hsync = hsync_counter_ != (registers_[3] & 15);
bus_state_.hsync = hsync_counter_ != layout_.horizontal.sync_width;
hsync_counter_ = (hsync_counter_ + 1) & 15;
break;
default:
hsync_counter_ = (hsync_counter_ + 1) & 15;
bus_state_.hsync = hsync_counter_ != (registers_[3] & 15);
bus_state_.hsync = hsync_counter_ != layout_.horizontal.sync_width;
break;
}
}
@ -234,7 +256,7 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
switch(personality) {
case Personality::HD6845S:
case Personality::AMS40226:
bus_state_.vsync = vsync_counter_ != (registers_[3] >> 4);
bus_state_.vsync = vsync_counter_ != layout_.vertical.sync_lines;
break;
default:
bus_state_.vsync = vsync_counter_ != 0;
@ -244,7 +266,7 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
if(is_in_adjustment_period_) {
line_counter_++;
if(line_counter_ == registers_[5]) {
if(line_counter_ == layout_.vertical.adjust) {
is_in_adjustment_period_ = false;
do_end_of_frame();
}
@ -255,8 +277,8 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
line_address_ = end_of_line_address_;
// Check for entry into the overflow area.
if(line_counter_ == registers_[4]) {
if(registers_[5]) {
if(line_counter_ == layout_.vertical.total) {
if(layout_.vertical.adjust) {
line_counter_ = 0;
is_in_adjustment_period_ = true;
} else {
@ -272,7 +294,7 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
}
// Check for end of visible lines.
if(line_counter_ == registers_[6]) {
if(line_counter_ == layout_.vertical.displayed) {
line_is_visible_ = false;
}
}
@ -322,7 +344,15 @@ template <class BusHandlerT, Personality personality, CursorType cursor_type> cl
uint8_t total;
uint8_t displayed;
uint8_t start_blank;
uint8_t sync_width;
} horizontal;
struct {
uint8_t total;
uint8_t displayed;
uint8_t sync_lines;
uint8_t adjust;
} vertical;
} layout_;
uint8_t registers_[18]{};