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Make cursor blink.

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This commit is contained in:
Thomas Harte 2023-12-04 09:52:46 -05:00
parent 0d7646d42a
commit 646c6b08f7
1 changed files with 27 additions and 7 deletions
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34
Components/6845/CRTC6845.hpp
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@ -65,7 +65,7 @@ enum CursorType {
// TODO UM6845R and R12/R13; see http://www.cpcwiki.eu/index.php/CRTC#CRTC_Differences
template <class T, CursorType cursor> class CRTC6845 {
template <class T, CursorType cursor_type> class CRTC6845 {
public:
CRTC6845(Personality p, T &bus_handler) noexcept :
@ -136,7 +136,7 @@ template <class T, CursorType cursor> class CRTC6845 {
bus_state_.refresh_address = (bus_state_.refresh_address + 1) & 0x3fff;
bus_state_.cursor = is_cursor_line_ &&
bus_state_.refresh_address == ((registers_[15] | (registers_[14] << 8))&0x3fff);
bus_state_.refresh_address == (registers_[15] | (registers_[14] << 8));
// Check for end-of-line.
if(character_counter_ == registers_[0]) {
@ -192,9 +192,11 @@ template <class T, CursorType cursor> class CRTC6845 {
}
inline void do_end_of_line() {
// Check for cursor disable.
// TODO: this is handled differently on the EGA, should I ever implement that.
is_cursor_line_ &= bus_state_.row_address != (registers_[11] & 0x1f);
if constexpr (cursor_type != CursorType::None) {
// Check for cursor disable.
// TODO: this is handled differently on the EGA, should I ever implement that.
is_cursor_line_ &= bus_state_.row_address != (registers_[11] & 0x1f);
}
// Check for end of vertical sync.
if(bus_state_.vsync) {
@ -255,8 +257,21 @@ template <class T, CursorType cursor> class CRTC6845 {
character_counter_ = 0;
character_is_visible_ = (registers_[1] != 0);
// Check for cursor enable.
is_cursor_line_ |= bus_state_.row_address == (registers_[10] & 0x1f);
if constexpr (cursor_type != CursorType::None) {
// Check for cursor enable.
is_cursor_line_ |= bus_state_.row_address == (registers_[10] & 0x1f);
switch(cursor_type) {
// MDA-style blinking; timings are a bit of a guess for now.
case CursorType::MDA:
switch(registers_[10] >> 5) {
case 0b11: is_cursor_line_ &= (field_count_ & 15) < 5; break;
case 0b00: is_cursor_line_ &= bool(field_count_ & 16); break;
default: break;
}
break;
}
}
}
inline void do_end_of_frame() {
@ -264,6 +279,9 @@ template <class T, CursorType cursor> class CRTC6845 {
line_is_visible_ = true;
line_address_ = uint16_t((registers_[12] << 8) | registers_[13]);
bus_state_.refresh_address = line_address_;
if constexpr (cursor_type != CursorType::None) {
++field_count_;
}
}
Personality personality_;
@ -291,6 +309,8 @@ template <class T, CursorType cursor> class CRTC6845 {
unsigned int character_is_visible_shifter_ = 0;
bool is_cursor_line_ = false;
int field_count_ = 0;
};
}