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87 lines
1.6 KiB
C++
87 lines
1.6 KiB
C++
//
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// Audio.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 20/03/2024.
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// Copyright © 2024 Thomas Harte. All rights reserved.
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//
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#pragma once
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#include <cstdint>
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namespace Archimedes {
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/// Models the Archimedes sound output; in a real machine this is a joint efort between the VIDC and the MEMC.
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template <typename InterruptObserverT>
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struct Sound {
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Sound(InterruptObserverT &observer) : observer_(observer) {}
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void set_next_end(uint32_t value) {
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next_.end = value;
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}
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void set_next_start(uint32_t value) {
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next_.start = value;
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set_buffer_valid(true); // My guess: this is triggered on next buffer start write.
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}
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bool interrupt() const {
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return !next_buffer_valid_;
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}
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void swap() {
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current_.start = next_.start;
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std::swap(current_.end, next_.end);
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set_buffer_valid(false);
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halted_ = false;
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}
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void set_frequency(uint8_t frequency) {
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divider_ = reload_ = frequency;
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}
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void set_stereo_image([[maybe_unused]] uint8_t channel, [[maybe_unused]] uint8_t value) {
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// TODO.
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}
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void tick() {
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if(halted_) {
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return;
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}
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--divider_;
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if(divider_) return;
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divider_ = reload_;
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current_.start += 16;
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if(current_.start == current_.end) {
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if(next_buffer_valid_) {
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swap();
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} else {
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halted_ = true;
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}
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}
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}
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private:
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uint8_t divider_ = 0, reload_ = 0;
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void set_buffer_valid(bool valid) {
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next_buffer_valid_ = valid;
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observer_.update_sound_interrupt();
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}
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bool next_buffer_valid_ = false;
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bool halted_ = true; // This is a bit of a guess.
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struct Buffer {
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uint32_t start = 0, end = 0;
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};
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Buffer current_, next_;
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InterruptObserverT &observer_;
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};
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}
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