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Introduces equalisation pulses for the Apple II.

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This commit is contained in:
Thomas Harte 2018-06-23 22:11:39 -04:00
parent e48ba89721
commit 55ab305dbf
1 changed files with 16 additions and 2 deletions
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18
Machines/AppleII/Video.hpp
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@ -88,11 +88,25 @@ template <class BusHandler> class Video: public VideoBase {
int int_cycles = cycles.as_int();
while(int_cycles) {
const int cycles_this_line = std::min(65 - column_, int_cycles);
const int ending_column = column_ + cycles_this_line;
if(row_ >= first_sync_line && row_ < first_sync_line + 3) {
crt_->output_sync(static_cast<unsigned int>(cycles_this_line) * 14);
// In effect apply an XOR to HSYNC and VSYNC flags in order to include equalising
// pulses (and hencce keep hsync approximately where it should be during vsync).
const int blank_start = std::max(first_sync_column, column_);
const int blank_end = std::min(first_sync_column + 4, ending_column);
if(blank_end > blank_start) {
if(blank_start > column_) {
crt_->output_sync(static_cast<unsigned int>(blank_start - column_) * 14);
}
crt_->output_blank(static_cast<unsigned int>(blank_end - blank_start) * 14);
if(blank_end < ending_column) {
crt_->output_sync(static_cast<unsigned int>(ending_column - blank_end) * 14);
}
} else {
crt_->output_sync(static_cast<unsigned int>(cycles_this_line) * 14);
}
} else {
const int ending_column = column_ + cycles_this_line;
const GraphicsMode line_mode = use_graphics_mode_ ? graphics_mode_ : GraphicsMode::Text;
// The first 40 columns are submitted to the CRT only upon completion;