169 lines
8.0 KiB
C++
169 lines
8.0 KiB
C++
//
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// 6847.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 04/05/2026.
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// Copyright © 2026 Thomas Harte. All rights reserved.
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//
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#include "6847.hpp"
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#include <cstdint>
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namespace {
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static constexpr uint8_t font[64][12] = {
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x02, 0x1a, 0x2a, 0x2a, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x08, 0x14, 0x22, 0x22, 0x3e, 0x22, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3c, 0x12, 0x12, 0x1c, 0x12, 0x12, 0x3c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x20, 0x20, 0x20, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3c, 0x12, 0x12, 0x12, 0x12, 0x12, 0x3c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3e, 0x20, 0x20, 0x3c, 0x20, 0x20, 0x3e, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3e, 0x20, 0x20, 0x3c, 0x20, 0x20, 0x20, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1e, 0x20, 0x20, 0x26, 0x22, 0x22, 0x1e, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x22, 0x22, 0x3e, 0x22, 0x22, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x08, 0x08, 0x08, 0x08, 0x08, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x02, 0x02, 0x02, 0x02, 0x22, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x24, 0x28, 0x30, 0x28, 0x24, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x3e, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x36, 0x2a, 0x2a, 0x22, 0x22, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x32, 0x2a, 0x26, 0x22, 0x22, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3e, 0x22, 0x22, 0x22, 0x22, 0x22, 0x3e, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3c, 0x22, 0x22, 0x3c, 0x20, 0x20, 0x20, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x22, 0x22, 0x2a, 0x24, 0x1a, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3c, 0x22, 0x22, 0x3c, 0x28, 0x24, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x10, 0x08, 0x04, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3e, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x22, 0x22, 0x14, 0x14, 0x08, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x22, 0x22, 0x2a, 0x2a, 0x36, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x22, 0x14, 0x08, 0x14, 0x22, 0x22, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x22, 0x22, 0x14, 0x08, 0x08, 0x08, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3e, 0x02, 0x04, 0x08, 0x10, 0x20, 0x3e, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x38, 0x20, 0x20, 0x20, 0x20, 0x20, 0x38, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x20, 0x20, 0x10, 0x08, 0x04, 0x02, 0x02, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x0e, 0x02, 0x02, 0x02, 0x02, 0x02, 0x0e, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x08, 0x1c, 0x2a, 0x08, 0x08, 0x08, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x08, 0x10, 0x3e, 0x10, 0x08, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x08, 0x08, 0x08, 0x08, 0x08, 0x00, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x14, 0x14, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x14, 0x14, 0x36, 0x00, 0x36, 0x14, 0x14, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x08, 0x1e, 0x20, 0x1c, 0x02, 0x3c, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x32, 0x32, 0x04, 0x08, 0x10, 0x26, 0x26, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x10, 0x28, 0x28, 0x10, 0x2a, 0x24, 0x1a, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x18, 0x18, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x08, 0x10, 0x20, 0x20, 0x20, 0x10, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x08, 0x04, 0x02, 0x02, 0x02, 0x04, 0x08, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x08, 0x1c, 0x3e, 0x1c, 0x08, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x08, 0x08, 0x3e, 0x08, 0x08, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x30, 0x10, 0x20, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3e, 0x00, 0x00, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x30, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x02, 0x02, 0x04, 0x08, 0x10, 0x20, 0x20, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x18, 0x24, 0x24, 0x24, 0x24, 0x24, 0x18, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x08, 0x18, 0x08, 0x08, 0x08, 0x08, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x02, 0x1c, 0x20, 0x20, 0x3e, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x02, 0x0c, 0x02, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x04, 0x0c, 0x14, 0x3e, 0x04, 0x04, 0x04, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3e, 0x20, 0x3c, 0x02, 0x02, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x20, 0x20, 0x3c, 0x22, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x3e, 0x02, 0x04, 0x08, 0x10, 0x20, 0x20, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x22, 0x1c, 0x22, 0x22, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x1c, 0x22, 0x22, 0x1e, 0x02, 0x02, 0x1c, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x18, 0x18, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x18, 0x18, 0x00, 0x18, 0x18, 0x08, 0x10, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x04, 0x08, 0x10, 0x20, 0x10, 0x08, 0x04, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x3e, 0x00, 0x3e, 0x00, 0x00, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x10, 0x08, 0x04, 0x02, 0x04, 0x08, 0x10, 0x00, 0x00, },
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{ 0x00, 0x00, 0x00, 0x18, 0x24, 0x04, 0x08, 0x08, 0x00, 0x08, 0x00, 0x00, },
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};
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static constexpr int CRTMultiplier = 14;
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}
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using namespace Motorola::MC6847;
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// TODO: the real 6847 is in-phase, but I don't currently know whether it's 228 colour cycles per line or 227.
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// So the below isn't quite accurate. This is something to figure out.
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MC6847Base::MC6847Base(const Outputs::Display::Type display_type) :
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crt_(
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910,
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1,
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display_type,
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Outputs::Display::InputDataType::Red4Green4Blue4 // TODO.
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) {
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crt_.set_display_type(Outputs::Display::DisplayType::CompositeColour);
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}
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void MC6847Base::pixel_line(const int line, const int line_begin, const int line_end) {
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Numeric::clamp<0, LineLayout::EndOfSync>(line_begin, line_end, [&](int, const int end) {
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if(end == LineLayout::EndOfSync) {
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crt_.output_sync(LineLayout::EndOfSync * CRTMultiplier);
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}
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});
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Numeric::clamp<LineLayout::EndOfSync, LineLayout::EndOfLeftBorder>(line_begin, line_end, [&](int, const int end) {
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if(end == LineLayout::EndOfLeftBorder) {
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crt_.output_blank((LineLayout::EndOfLeftBorder - LineLayout::EndOfSync) * CRTMultiplier);
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}
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});
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Numeric::clamp<LineLayout::EndOfLeftBorder, LineLayout::EndOfPixels>(
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line_begin,
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line_end,
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[&](const int begin, const int end) {
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if(begin == LineLayout::EndOfLeftBorder) {
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pixels_ = reinterpret_cast<uint16_t *>(crt_.begin_data(256));
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}
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// TODO: obey graphics mode here, use proper colours, more.
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if(pixels_) {
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const int row = address_.row();
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for(int c = line_begin; c < line_end; c++) {
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const int column = c - LineLayout::EndOfLeftBorder;
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const int pixels = font[line_.data[column] & 63][row];
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pixels_[0] = (pixels & 0x80) ? 0xffff : 0x0000;
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pixels_[1] = (pixels & 0x40) ? 0xffff : 0x0000;
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pixels_[2] = (pixels & 0x20) ? 0xffff : 0x0000;
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pixels_[3] = (pixels & 0x10) ? 0xffff : 0x0000;
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pixels_[4] = (pixels & 0x08) ? 0xffff : 0x0000;
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pixels_[5] = (pixels & 0x04) ? 0xffff : 0x0000;
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pixels_[6] = (pixels & 0x02) ? 0xffff : 0x0000;
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pixels_[7] = (pixels & 0x01) ? 0xffff : 0x0000;
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pixels_ += 8;
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}
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}
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if(end == LineLayout::EndOfPixels) {
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crt_.output_data(32 * CRTMultiplier, 256);
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address_.apply_hsync();
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printf("\n");
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}
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}
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);
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Numeric::clamp<LineLayout::EndOfPixels, LineLayout::EndOfLine>(line_begin, line_end, [&](int, const int end) {
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if(end == LineLayout::EndOfLine) {
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crt_.output_blank((LineLayout::EndOfLine - LineLayout::EndOfPixels) * CRTMultiplier);
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}
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});
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}
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void MC6847Base::border_line(const int, const int end) {
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if(end == LineLayout::EndOfLine) {
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crt_.output_sync(LineLayout::EndOfSync * CRTMultiplier);
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crt_.output_blank((LineLayout::EndOfLine - LineLayout::EndOfSync) * CRTMultiplier);
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}
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}
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void MC6847Base::porch_line(const int begin, const int end) {
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border_line(begin, end);
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}
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void MC6847Base::sync_line(const int, const int end) {
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if(end == LineLayout::EndOfLine) {
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crt_.output_sync((LineLayout::EndOfLine) * CRTMultiplier);
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}
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}
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void MC6847Base::reset() {
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address_.apply_vertical_preload();
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}
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