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449 lines
14 KiB
C++
449 lines
14 KiB
C++
//
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// Video.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 10/12/2016.
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// Copyright 2016 Thomas Harte. All rights reserved.
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//
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#include "Video.hpp"
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#include <cstring>
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using namespace Electron;
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// MARK: - Lifecycle
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VideoOutput::VideoOutput(const uint8_t *memory) :
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ram_(memory),
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crt_(128,
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1,
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Outputs::Display::Type::PAL50,
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Outputs::Display::InputDataType::Red1Green1Blue1) {
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memset(palette_, 0xf, sizeof(palette_));
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// TODO: as implied below, I've introduced a clock's latency into the graphics pipeline somehow. Investigate.
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// crt_.set_visible_area(crt_.get_rect_for_area(first_graphics_line - 1, 256, (first_graphics_cycle+1) * crt_cycles_multiplier, 80 * crt_cycles_multiplier, 4.0f / 3.0f));
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}
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void VideoOutput::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
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crt_.set_scan_target(scan_target);
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}
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Outputs::Display::ScanStatus VideoOutput::get_scaled_scan_status() const {
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return crt_.get_scaled_scan_status();// / float(crt_cycles_multiplier);
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}
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void VideoOutput::set_display_type(Outputs::Display::DisplayType display_type) {
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crt_.set_display_type(display_type);
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}
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Outputs::Display::DisplayType VideoOutput::get_display_type() const {
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return crt_.get_display_type();
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}
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// MARK: - Display update methods
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//void VideoOutput::start_pixel_line() {
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// current_pixel_line_ = (current_pixel_line_+1)&255;
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// if(!current_pixel_line_) {
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// start_line_address_ = start_screen_address_;
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// current_character_row_ = 0;
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// is_blank_line_ = false;
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// } else {
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// bool mode_has_blank_lines = (screen_mode_ == 6) || (screen_mode_ == 3);
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// is_blank_line_ = (mode_has_blank_lines && ((current_character_row_ > 7 && current_character_row_ < 10) || (current_pixel_line_ > 249)));
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//
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// if(!is_blank_line_) {
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// start_line_address_++;
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//
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// if(current_character_row_ > 7) {
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// start_line_address_ += ((screen_mode_ < 4) ? 80 : 40) * 8 - 8;
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// current_character_row_ = 0;
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// }
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// }
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// }
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// current_screen_address_ = start_line_address_;
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// current_pixel_column_ = 0;
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// initial_output_target_ = current_output_target_ = nullptr;
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//}
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//
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//void VideoOutput::end_pixel_line() {
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// const int data_length = int(current_output_target_ - initial_output_target_);
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// if(data_length) {
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// crt_.output_data(data_length * current_output_divider_, size_t(data_length));
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// }
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// current_character_row_++;
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//}
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//
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//void VideoOutput::output_pixels(int number_of_cycles) {
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// if(!number_of_cycles) return;
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//
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// if(is_blank_line_) {
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// crt_.output_blank(number_of_cycles * crt_cycles_multiplier);
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// } else {
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// int divider = 1;
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// switch(screen_mode_) {
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// case 0: case 3: divider = 1; break;
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// case 1: case 4: case 6: divider = 2; break;
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// case 2: case 5: divider = 4; break;
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// }
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//
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// if(!initial_output_target_ || divider != current_output_divider_) {
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// const int data_length = int(current_output_target_ - initial_output_target_);
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// if(data_length) {
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// crt_.output_data(data_length * current_output_divider_, size_t(data_length));
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// }
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// current_output_divider_ = divider;
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// initial_output_target_ = current_output_target_ = crt_.begin_data(size_t(640 / current_output_divider_), size_t(8 / divider));
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// }
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//
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//#define get_pixel() \
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// if(current_screen_address_&32768) {\
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// current_screen_address_ = (screen_mode_base_address_ + current_screen_address_)&32767;\
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// }\
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// last_pixel_byte_ = ram_[current_screen_address_];\
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// current_screen_address_ = current_screen_address_+8
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//
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// switch(screen_mode_) {
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// case 0: case 3:
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// if(initial_output_target_) {
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// while(number_of_cycles--) {
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// get_pixel();
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// *reinterpret_cast<uint64_t *>(current_output_target_) = palette_tables_.eighty1bpp[last_pixel_byte_];
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// current_output_target_ += 8;
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// current_pixel_column_++;
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// }
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// } else current_output_target_ += 8*number_of_cycles;
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// break;
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//
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// case 1:
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// if(initial_output_target_) {
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// while(number_of_cycles--) {
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// get_pixel();
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// *reinterpret_cast<uint32_t *>(current_output_target_) = palette_tables_.eighty2bpp[last_pixel_byte_];
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// current_output_target_ += 4;
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// current_pixel_column_++;
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// }
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// } else current_output_target_ += 4*number_of_cycles;
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// break;
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//
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// case 2:
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// if(initial_output_target_) {
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// while(number_of_cycles--) {
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// get_pixel();
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// *reinterpret_cast<uint16_t *>(current_output_target_) = palette_tables_.eighty4bpp[last_pixel_byte_];
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// current_output_target_ += 2;
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// current_pixel_column_++;
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// }
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// } else current_output_target_ += 2*number_of_cycles;
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// break;
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//
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// case 4: case 6:
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// if(initial_output_target_) {
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// if(current_pixel_column_&1) {
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// last_pixel_byte_ <<= 4;
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// *reinterpret_cast<uint32_t *>(current_output_target_) = palette_tables_.forty1bpp[last_pixel_byte_];
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// current_output_target_ += 4;
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//
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// number_of_cycles--;
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// current_pixel_column_++;
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// }
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// while(number_of_cycles > 1) {
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// get_pixel();
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// *reinterpret_cast<uint32_t *>(current_output_target_) = palette_tables_.forty1bpp[last_pixel_byte_];
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// current_output_target_ += 4;
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//
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// last_pixel_byte_ <<= 4;
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// *reinterpret_cast<uint32_t *>(current_output_target_) = palette_tables_.forty1bpp[last_pixel_byte_];
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// current_output_target_ += 4;
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//
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// number_of_cycles -= 2;
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// current_pixel_column_+=2;
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// }
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// if(number_of_cycles) {
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// get_pixel();
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// *reinterpret_cast<uint32_t *>(current_output_target_) = palette_tables_.forty1bpp[last_pixel_byte_];
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// current_output_target_ += 4;
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// current_pixel_column_++;
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// }
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// } else current_output_target_ += 4 * number_of_cycles;
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// break;
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//
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// case 5:
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// if(initial_output_target_) {
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// if(current_pixel_column_&1) {
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// last_pixel_byte_ <<= 2;
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// *reinterpret_cast<uint16_t *>(current_output_target_) = palette_tables_.forty2bpp[last_pixel_byte_];
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// current_output_target_ += 2;
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//
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// number_of_cycles--;
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// current_pixel_column_++;
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// }
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// while(number_of_cycles > 1) {
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// get_pixel();
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// *reinterpret_cast<uint16_t *>(current_output_target_) = palette_tables_.forty2bpp[last_pixel_byte_];
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// current_output_target_ += 2;
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//
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// last_pixel_byte_ <<= 2;
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// *reinterpret_cast<uint16_t *>(current_output_target_) = palette_tables_.forty2bpp[last_pixel_byte_];
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// current_output_target_ += 2;
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//
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// number_of_cycles -= 2;
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// current_pixel_column_+=2;
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// }
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// if(number_of_cycles) {
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// get_pixel();
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// *reinterpret_cast<uint16_t *>(current_output_target_) = palette_tables_.forty2bpp[last_pixel_byte_];
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// current_output_target_ += 2;
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// current_pixel_column_++;
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// }
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// } else current_output_target_ += 2*number_of_cycles;
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// break;
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// }
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//
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//#undef get_pixel
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// }
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//}
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uint8_t VideoOutput::run_for(const Cycles cycles) {
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uint8_t interrupts{};
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int number_of_cycles = cycles.as<int>();
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while(number_of_cycles--) {
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// Horizontal and vertical counter updates.
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const bool is_v_end = v_count == v_total();
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h_count += 8;
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if(h_count == h_total) {
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h_count = 0;
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++v_count;
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if(is_v_end) {
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v_count = 0;
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field = !field;
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}
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}
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// Test for interrupts.
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if(v_count == v_rtc && ((!field && !h_count) || (field && h_count == h_half))) {
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interrupts |= static_cast<uint8_t>(Interrupt::RealTimeClock);
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}
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if(h_count == hsync_start && ((v_count == v_disp_gph && !mode_text) or (v_count == v_disp_txt && mode_text))) {
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interrupts |= static_cast<uint8_t>(Interrupt::DisplayEnd);
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}
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// Update syncs.
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if(!field) {
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if(!h_count && v_count == vsync_start) {
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vsync_int = true;
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} else if(h_count == h_half && v_count == vsync_end) {
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vsync_int = false;
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}
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} else {
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if(h_count == h_half && v_count == vsync_start) {
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vsync_int = true;
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} else if(!h_count && v_count == vsync_end + 1) {
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vsync_int = false;
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}
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}
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if(h_count == hsync_start) {
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hsync_int = true;
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} else if(h_count == hsync_end) {
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hsync_int = false;
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}
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// Update character row on the trailing edge of hsync.
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if(h_count == hsync_end) {
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if(is_v_end) {
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char_row = 0;
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} else {
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char_row = last_line() ? 0 : char_row + 1;
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}
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}
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// Disable the top bit of the char_row counter outside of text mode.
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if(!mode_text) {
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char_row &= 7;
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}
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// Latch video address at frame start.
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if(h_count == h_reset_addr && is_v_end) {
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row_addr = byte_addr = screen_base;
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}
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// Copy byte_addr back into row_addr if a new character row has begun.
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if(hsync_int) {
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if(last_line()) {
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row_addr = byte_addr;
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} else {
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byte_addr = row_addr;
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}
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}
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// Determine current output item.
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OutputStage stage;
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if(vsync_int || hsync_int) {
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stage = OutputStage::Sync;
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} else if(in_blank()) {
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stage = OutputStage::Blank;
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} else {
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stage = OutputStage::Pixels;
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}
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if(stage != output_) {
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switch(output_) {
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case OutputStage::Sync: crt_.output_sync(output_length_); break;
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case OutputStage::Blank: crt_.output_blank(output_length_); break;
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case OutputStage::Pixels:
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if(current_output_target_) {
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crt_.output_data(
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output_length_,
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static_cast<size_t>(current_output_target_ - initial_output_target_)
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);
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} else {
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crt_.output_data(output_length_);
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}
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break;
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}
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output_length_ = 0;
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output_ = stage;
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if(stage == OutputStage::Pixels) {
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initial_output_target_ = current_output_target_ = crt_.begin_data(640);//crt_.begin_data(mode_40 ? 320 : 640);
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}
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}
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++output_length_;
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if(output_ == OutputStage::Pixels && (!mode_40 || h_count & 8) && current_output_target_) {
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const uint8_t data = ram_[byte_addr | char_row];
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current_output_target_[0] = (data & 0x80) ? 0xff : 0x00;
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current_output_target_[1] = (data & 0x40) ? 0xff : 0x00;
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current_output_target_[2] = (data & 0x20) ? 0xff : 0x00;
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current_output_target_[3] = (data & 0x10) ? 0xff : 0x00;
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current_output_target_[4] = (data & 0x08) ? 0xff : 0x00;
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current_output_target_[5] = (data & 0x04) ? 0xff : 0x00;
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current_output_target_[6] = (data & 0x02) ? 0xff : 0x00;
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current_output_target_[7] = (data & 0x01) ? 0xff : 0x00;
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current_output_target_ += 8;
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}
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// Increment the byte address across the line.
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// (slghtly pained logic here because the input clock is still at the pixel rate, not the byte rate)
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if(h_count < h_active) {
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if(
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(!mode_40 && !(h_count & 0x7)) ||
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(mode_40 && ((h_count & 0xf) == 0x8))
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) {
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byte_addr += 8;
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if(!(byte_addr & 0b0111'1000'0000'0000)) {
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byte_addr = mode_base | (byte_addr & 0x0000'0111'1111'1111);
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}
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}
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}
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}
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return interrupts;
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}
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// MARK: - Register hub
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void VideoOutput::write(int address, uint8_t value) {
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switch(address & 0xf) {
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case 0x02:
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screen_base =
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(screen_base & 0b0111'1110'0000'0000) |
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((value << 1) & 0b0000'0001'1100'0000);
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break;
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case 0x03:
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screen_base =
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((value << 9) & 0b0111'1110'0000'0000) |
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(screen_base & 0b0000'0001'1100'0000);
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break;
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case 0x07: {
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uint8_t mode = (value >> 3)&7;
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mode_40 = mode >= 4;
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mode_text = mode == 3 || mode == 6;
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switch(mode) {
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case 0:
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case 1:
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case 2: mode_base = 0x3000; break;
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case 3: mode_base = 0x4000; break;
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case 6: mode_base = 0x6000; break;
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default: mode_base = 0x5800; break;
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}
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switch(mode) {
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default: mode_bpp = Bpp::One; break;
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case 1:
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case 5: mode_bpp = Bpp::Two; break;
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case 2: mode_bpp = Bpp::Four; break;
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}
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} break;
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case 0x08: case 0x09: case 0x0a: case 0x0b:
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case 0x0c: case 0x0d: case 0x0e: case 0x0f: {
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// constexpr int registers[4][4] = {
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// {10, 8, 2, 0},
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// {14, 12, 6, 4},
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// {15, 13, 7, 5},
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// {11, 9, 3, 1},
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// };
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// const int index = (address >> 1)&3;
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// const uint8_t colour = ~value;
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// if(address&1) {
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// palette_[registers[index][0]] = (palette_[registers[index][0]]&3) | ((colour >> 1)&4);
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// palette_[registers[index][1]] = (palette_[registers[index][1]]&3) | ((colour >> 0)&4);
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// palette_[registers[index][2]] = (palette_[registers[index][2]]&3) | ((colour << 1)&4);
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// palette_[registers[index][3]] = (palette_[registers[index][3]]&3) | ((colour << 2)&4);
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//
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// palette_[registers[index][2]] = (palette_[registers[index][2]]&5) | ((colour >> 4)&2);
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// palette_[registers[index][3]] = (palette_[registers[index][3]]&5) | ((colour >> 3)&2);
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// } else {
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// palette_[registers[index][0]] = (palette_[registers[index][0]]&6) | ((colour >> 7)&1);
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// palette_[registers[index][1]] = (palette_[registers[index][1]]&6) | ((colour >> 6)&1);
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// palette_[registers[index][2]] = (palette_[registers[index][2]]&6) | ((colour >> 5)&1);
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// palette_[registers[index][3]] = (palette_[registers[index][3]]&6) | ((colour >> 4)&1);
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//
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// palette_[registers[index][0]] = (palette_[registers[index][0]]&5) | ((colour >> 2)&2);
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// palette_[registers[index][1]] = (palette_[registers[index][1]]&5) | ((colour >> 1)&2);
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// }
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//
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// // regenerate all palette tables for now
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// for(int byte = 0; byte < 256; byte++) {
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// uint8_t *target = reinterpret_cast<uint8_t *>(&palette_tables_.forty1bpp[byte]);
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// target[0] = palette_[(byte&0x80) >> 4];
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// target[1] = palette_[(byte&0x40) >> 3];
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// target[2] = palette_[(byte&0x20) >> 2];
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// target[3] = palette_[(byte&0x10) >> 1];
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//
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// target = reinterpret_cast<uint8_t *>(&palette_tables_.eighty2bpp[byte]);
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// target[0] = palette_[((byte&0x80) >> 4) | ((byte&0x08) >> 2)];
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// target[1] = palette_[((byte&0x40) >> 3) | ((byte&0x04) >> 1)];
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// target[2] = palette_[((byte&0x20) >> 2) | ((byte&0x02) >> 0)];
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// target[3] = palette_[((byte&0x10) >> 1) | ((byte&0x01) << 1)];
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//
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// target = reinterpret_cast<uint8_t *>(&palette_tables_.eighty1bpp[byte]);
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// target[0] = palette_[(byte&0x80) >> 4];
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// target[1] = palette_[(byte&0x40) >> 3];
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// target[2] = palette_[(byte&0x20) >> 2];
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// target[3] = palette_[(byte&0x10) >> 1];
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// target[4] = palette_[(byte&0x08) >> 0];
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// target[5] = palette_[(byte&0x04) << 1];
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// target[6] = palette_[(byte&0x02) << 2];
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// target[7] = palette_[(byte&0x01) << 3];
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//
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// target = reinterpret_cast<uint8_t *>(&palette_tables_.forty2bpp[byte]);
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// target[0] = palette_[((byte&0x80) >> 4) | ((byte&0x08) >> 2)];
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// target[1] = palette_[((byte&0x40) >> 3) | ((byte&0x04) >> 1)];
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//
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// target = reinterpret_cast<uint8_t *>(&palette_tables_.eighty4bpp[byte]);
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// target[0] = palette_[((byte&0x80) >> 4) | ((byte&0x20) >> 3) | ((byte&0x08) >> 2) | ((byte&0x02) >> 1)];
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// target[1] = palette_[((byte&0x40) >> 3) | ((byte&0x10) >> 2) | ((byte&0x04) >> 1) | ((byte&0x01) >> 0)];
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// }
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} break;
|
|
}
|
|
}
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|
|