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321 lines
8.8 KiB
C++
321 lines
8.8 KiB
C++
//
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// OPL2.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 02/04/2020.
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// Copyright © 2020 Thomas Harte. all rights reserved.
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//
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#include "OPL2.hpp"
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#include <cassert>
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#include <cmath>
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#include "Implementation/Tables.h"
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using namespace Yamaha::OPL;
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template <typename Child>
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OPLBase<Child>::OPLBase(Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {}
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template <typename Child>
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void OPLBase<Child>::write(uint16_t address, uint8_t value) {
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if(address & 1) {
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static_cast<Child *>(this)->write_register(selected_register_, value);
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} else {
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selected_register_ = value;
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}
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}
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template class Yamaha::OPL::OPLBase<Yamaha::OPL::OPLL>;
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template class Yamaha::OPL::OPLBase<Yamaha::OPL::OPL2>;
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OPLL::OPLL(Concurrency::DeferringAsyncTaskQueue &task_queue, int audio_divider, bool is_vrc7): OPLBase(task_queue), audio_divider_(audio_divider) {
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// Due to the way that sound mixing works on the OPLL, the audio divider may not
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// be larger than 2.
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assert(audio_divider <= 2);
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// Install fixed instruments.
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const uint8_t *patch_set = is_vrc7 ? vrc7_patch_set : opll_patch_set;
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for(int c = 0; c < 15; ++c) {
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setup_fixed_instrument(c+1, patch_set);
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patch_set += 8;
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}
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// Install rhythm patches.
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for(int c = 0; c < 3; ++c) {
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setup_fixed_instrument(c+16, &percussion_patch_set[c * 8]);
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}
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// Set default modulators.
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for(int c = 0; c < 9; ++c) {
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channels_[c].modulator = &operators_[0];
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}
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}
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bool OPLL::is_zero_level() {
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// for(int c = 0; c < 9; ++c) {
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// if(channels_[c].is_audible()) return false;
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// }
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return false;
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}
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void OPLL::get_samples(std::size_t number_of_samples, std::int16_t *target) {
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// Both the OPLL and the OPL2 divide the input clock by 72 to get the base tick frequency;
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// unlike the OPL2 the OPLL time-divides the output for 'mixing'.
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const int update_period = 72 / audio_divider_;
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const int channel_output_period = 8 / audio_divider_;
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// Fill in any leftover from the previous session.
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if(audio_offset_) {
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while(audio_offset_ < update_period && number_of_samples) {
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*target = int16_t(channels_[audio_offset_ / channel_output_period].level);
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++target;
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++audio_offset_;
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--number_of_samples;
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}
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audio_offset_ = 0;
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}
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// End now if that provided everything that was asked for.
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if(!number_of_samples) return;
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int total_updates = int(number_of_samples) / update_period;
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number_of_samples %= size_t(update_period);
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audio_offset_ = int(number_of_samples);
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while(total_updates--) {
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update_all_chanels();
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for(int c = 0; c < update_period; ++c) {
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*target = int16_t(channels_[c / channel_output_period].level);
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++target;
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}
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}
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// If there are any other spots remaining, fill them.
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if(number_of_samples) {
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update_all_chanels();
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for(int c = 0; c < int(number_of_samples); ++c) {
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*target = int16_t(channels_[c / channel_output_period].level);
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++target;
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}
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}
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}
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void OPLL::set_sample_volume_range(std::int16_t range) {
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total_volume_ = range;
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}
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uint8_t OPLL::read(uint16_t address) {
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// I've seen mention of an undocumented two-bit status register. I don't yet know what is in it.
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return 0xff;
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}
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void OPLL::write_register(uint8_t address, uint8_t value) {
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// The OPLL doesn't have timers or other non-audio functions, so all writes
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// go to the audio queue.
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task_queue_.defer([this, address, value] {
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// The first 8 locations are used to define the custom instrument, and have
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// exactly the same format as the patch set arrays at the head of this file.
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if(address < 8) {
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custom_instrument_[address] = value;
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// Update whatever that did to the instrument.
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setup_fixed_instrument(0, custom_instrument_);
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return;
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}
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// Register 0xe is a cut-down version of the OPLL's register 0xbd.
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if(address == 0xe) {
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depth_rhythm_control_ = value & 0x3f;
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return;
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}
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const auto index = address & 0xf;
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if(index > 8) return;
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switch(address & 0xf0) {
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case 0x30:
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// Select an instrument in the top nibble, set a channel volume in the lower.
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channels_[index].overrides.attenuation = value & 0xf;
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channels_[index].modulator = &operators_[(value >> 4) * 2];
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break;
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case 0x10: channels_[index].set_frequency_low(value); break;
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case 0x20:
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// Set sustain on/off, key on/off, octave and a single extra bit of frequency.
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// So they're a lot like OPLL registers 0xb0 to 0xb8, but not identical.
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channels_[index].set_9bit_frequency_octave_key_on(value);
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channels_[index].overrides.use_sustain_level = value & 0x20;
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break;
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default: break;
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}
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});
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}
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void OPLL::setup_fixed_instrument(int number, const uint8_t *data) {
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auto modulator = &operators_[number * 2];
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auto carrier = &operators_[number * 2 + 1];
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modulator->set_am_vibrato_hold_sustain_ksr_multiple(data[0]);
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carrier->set_am_vibrato_hold_sustain_ksr_multiple(data[1]);
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modulator->set_scaling_output(data[2]);
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// Set waveforms — only sine and halfsine are available.
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carrier->set_waveform((data[3] >> 4) & 1);
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modulator->set_waveform((data[3] >> 3) & 1);
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// TODO: data[3] b0-b2: modulator feedback level
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// TODO: data[3] b6, b7: carrier key-scale level
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// Set ADSR parameters.
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modulator->set_attack_decay(data[4]);
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carrier->set_attack_decay(data[5]);
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modulator->set_sustain_release(data[6]);
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carrier->set_sustain_release(data[7]);
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}
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void OPLL::update_all_chanels() {
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if(depth_rhythm_control_ & 0x20) {
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// Rhythm mode. Somehow?
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// Melodic channels. Easy!
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for(int c = 0; c < 6; ++ c) {
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channels_[c].level = (channels_[c].update() * total_volume_) >> 14;
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}
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} else {
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// All melody, all the time.
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for(int c = 0; c < 9; ++ c) {
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channels_[c].level = (channels_[c].update() * total_volume_) >> 14;
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}
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}
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// channels_[2].level = (channels_[2].update() * total_volume_) >> 14;
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}
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/*
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template <Personality personality>
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void OPL2<personality>::get_samples(std::size_t number_of_samples, std::int16_t *target) {
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// TODO.
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// out = exp(logsin(phase2 + exp(logsin(phase1) + gain1)) + gain2)
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// Melodic channels are:
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//
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// Channel Operator 1 Operator 2
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// 0 0 3
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// 1 1 4
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// 2 2 5
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// 3 6 9
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// 4 7 10
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// 5 8 11
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// 6 12 15
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// 7 13 16
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// 8 14 17
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//
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// In percussion mode, only channels 0–5 are use as melodic, with 6, 7 and 8 being
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// replaced by:
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//
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// Bass drum, using operators 12 and 15;
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// Snare, using operator 16;
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// Tom tom, using operator 14,
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// Cymbal, using operator 17; and
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// Symbol, using operator 13.
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}
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*/
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void OPL2::write_register(uint8_t address, uint8_t value) {
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// Deal with timer changes synchronously.
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switch(address) {
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case 0x02: timers_[0] = value; return;
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case 0x03: timers_[1] = value; return;
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case 0x04: timer_control_ = value; return;
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// TODO from register 4:
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// b7 = IRQ reset;
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// b6/b5 = timer 1/2 mask (irq enabling flags, I think?)
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// b4/b3 = timer 2/1 start (seemingly the opposite order to b6/b5?)
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default: break;
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}
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// Enqueue any changes that affect audio output.
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task_queue_.enqueue([this, address, value] {
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//
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// Modal modifications.
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//
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switch(address) {
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case 0x01: waveform_enable_ = value & 0x20; break;
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case 0x08:
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// b7: "composite sine wave mode on/off"?
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csm_keyboard_split_ = value;
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// b6: "Controls the split point of the keyboard. When 0, the keyboard split is the
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// second bit from the bit 8 of the F-Number. When 1, the MSB of the F-Number is used."
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break;
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case 0xbd: depth_rhythm_control_ = value; break;
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default: break;
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}
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//
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// Operator modifications.
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//
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if((address >= 0x20 && address < 0xa0) || address >= 0xe0) {
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// The 18 operators are spreat out across 22 addresses; each group of
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// six is framed within an eight-byte area thusly:
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constexpr int operator_by_address[] = {
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0, 1, 2, 3, 4, 5, -1, -1,
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6, 7, 8, 9, 10, 11, -1, -1,
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12, 13, 14, 15, 16, 17, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1,
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};
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const auto index = operator_by_address[address & 0x1f];
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if(index == -1) return;
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switch(address & 0xe0) {
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case 0x20: operators_[index].set_am_vibrato_hold_sustain_ksr_multiple(value); break;
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case 0x40: operators_[index].set_scaling_output(value); break;
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case 0x60: operators_[index].set_attack_decay(value); break;
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case 0x80: operators_[index].set_sustain_release(value); break;
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case 0xe0: operators_[index].set_waveform(value); break;
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default: break;
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}
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}
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//
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// Channel modifications.
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//
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const auto index = address & 0xf;
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if(index > 8) return;
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switch(address & 0xf0) {
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case 0xa0: channels_[index].set_frequency_low(value); break;
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case 0xb0: channels_[index].set_10bit_frequency_octave_key_on(value); break;
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case 0xc0: channels_[index].set_feedback_mode(value); break;
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default: break;
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}
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});
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}
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uint8_t OPL2::read(uint16_t address) {
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// TODO. There's a status register where:
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// b7 = IRQ status (set if interrupt request ongoing)
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// b6 = timer 1 flag (set if timer 1 expired)
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// b5 = timer 2 flag
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return 0xff;
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}
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