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Merge pull request #1449 from TomHarte/FullerAudio
Switch to full-clock PWM audio implementation, with noise generator.
This commit is contained in:
Thomas Harte
GitHub
commit
58ef91a7b1
@ -13,12 +13,6 @@
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namespace Commodore::Plus4 {
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// PAL: / 160 i.e. 5*32
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// NTSC: / 128 i.e. 4*32
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// 111860.78125 = NTSC
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// 110840.46875 = PAL
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class Audio: public Outputs::Speaker::BufferSource<Audio, false> {
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public:
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Audio(Concurrency::AsyncTaskQueue<false> &audio_queue) :
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@ -26,88 +20,126 @@ public:
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template <Outputs::Speaker::Action action>
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void apply_samples(std::size_t size, Outputs::Speaker::MonoSample *const target) {
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const auto count_frequency = [&](int index) {
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++counts_[index];
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if(counts_[index] == (frequencies_[index] ^ 1023) * frequency_multiplier_) {
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states_[index] ^= 1;
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counts_[index] = 0;
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} else if(counts_[index] == 1024 * frequency_multiplier_) {
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counts_[index] = 0;
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// Divide by frequency_multiplier_ and multiply by 8 to get the "8Mhz clock".
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// Each 32-window cycle of that clock is a single complete tick of the audio engine.
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const auto update_channel = [&](int channel) {
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if(sound_dc_ || channels_[channel].count == 0x3ff) {
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channels_[channel].count = (channels_[channel].frequency + 1) & 0x3ff;
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} else {
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++channels_[channel].count;
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if(channels_[channel].count == 0x3ff) {
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channels_[channel].state ^= 1;
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}
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}
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channels_[channel].pwm_count = 0;
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};
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if(sound_dc_) {
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Outputs::Speaker::fill<action>(target, target + size, Outputs::Speaker::MonoSample(volume_ * 2));
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} else {
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// TODO: noise generation.
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const auto update_noise = [&] {
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noise_ <<= 1;
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noise_ |= 1 ^ (noise_ >> 7) ^ (noise_ >> 5) ^ (noise_ >> 4) ^ (noise_ >> 1);
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};
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for(size_t c = 0; c < size; c++) {
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count_frequency(0);
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count_frequency(1);
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for(size_t c = 0; c < size; c++) {
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subcycle_ = (subcycle_ + 1) & 31;
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Outputs::Speaker::apply<action>(
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target[c],
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Outputs::Speaker::MonoSample(
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(
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((states_[0] & masks_[0]) * external_volume_) +
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((states_[1] & masks_[1]) * external_volume_)
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) * volume_
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));
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if(subcycle_ == 0) update_channel(0);
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if(subcycle_ == 16) {
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update_channel(1);
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update_noise();
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}
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++ channels_[0].pwm_count;
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++ channels_[1].pwm_count;
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if(sound_dc_) {
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channels_[0].state = 0;
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channels_[1].state = 0;
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noise_ = 0;
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}
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target[c] =
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external_volume_ * (
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((channels_[0].pwm_count < volume_) & channels_[0].enabled & ~channels_[0].state) |
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((channels_[1].pwm_count < volume_) &
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(
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(channels_[1].enabled & ~channels_[1].state) |
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(sound2_noise_on_ & noise_ & 1)
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)
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)
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);
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}
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r_ += size;
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}
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void set_sample_volume_range(const std::int16_t range) {
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external_volume_ = range / (2 * 9); // Two channels and nine output levels.
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external_volume_ = range; // / (2 * 9); // Two channels and nine output levels.
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}
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bool is_zero_level() const {
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return !(masks_[0] || masks_[1] || sound2_noise_on_) || !volume_;
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return !(channels_[0].enabled || channels_[1].enabled || sound2_noise_on_) || !volume_;
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}
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template <int channel> void set_frequency_low(uint8_t value) {
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audio_queue_.enqueue([this, value] {
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frequencies_[channel] = (frequencies_[channel] & 0xff00) | value;
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channels_[channel].frequency = (channels_[channel].frequency & 0xff00) | value;
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});
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}
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template <int channel> void set_frequency_high(uint8_t value) {
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audio_queue_.enqueue([this, value] {
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frequencies_[channel] = (frequencies_[channel] & 0x00ff) | ((value&3) << 8);
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channels_[channel].frequency = (channels_[channel].frequency & 0x00ff) | ((value&3) << 8);
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});
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}
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void set_constrol(uint8_t value) {
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void set_control(const uint8_t value) {
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audio_queue_.enqueue([this, value] {
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switch(value & 0xf) {
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case 0: volume_ = 31; break;
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case 1: volume_ = 30; break;
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case 2: volume_ = 28; break;
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case 3: volume_ = 26; break;
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case 4: volume_ = 24; break;
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case 5: volume_ = 22; break;
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case 6: volume_ = 20; break;
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case 7: volume_ = 18; break;
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default: volume_ = 16; break;
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}
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volume_ = std::min(value & 0xf, 8); // Only nine volumes are available.
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masks_[0] = (value & 0x10) ? 1 : 0;
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masks_[1] = (value & 0x20) ? 1 : 0;
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channels_[0].enabled = (value & 0x10) ? 1 : 0;
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channels_[1].enabled = (value & 0x20) ? 1 : 0;
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sound2_noise_on_ = (value & 0x40) && !(value & 0x20);
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sound_dc_ = value & 0x80;
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});
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}
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void set_divider(const uint8_t value) {
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audio_queue_.enqueue([this, value] {
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frequency_multiplier_ = 32 * (value & 0x40 ? 4 : 5);
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});
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}
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private:
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// Calling-thread state.
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Concurrency::AsyncTaskQueue<false> &audio_queue_;
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// Audio-thread state.
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int16_t external_volume_ = 0;
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int frequencies_[2]{};
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int frequency_multiplier_ = 5;
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int counts_[2]{};
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int states_[2]{};
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int masks_[2]{};
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int subcycle_ = 0;
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struct Channel {
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int frequency = 0;
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int count = 0;
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int pwm_count = 0;
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int state = 0;
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int enabled = 0;
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} channels_[2];
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uint8_t noise_ = 0;
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bool sound2_noise_on_ = false;
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bool sound_dc_ = false;
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int volume_ = 0;
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int r_ = 0;
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};
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}
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@ -146,7 +146,7 @@ public:
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const auto clock = clock_rate(false);
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media_divider_ = Cycles(clock);
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set_clock_rate(clock);
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speaker_.set_input_rate(float(clock) / 32.0f);
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speaker_.set_input_rate(float(clock));
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// TODO: decide whether to attach a 1541 for real.
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const bool has_c1541 = true;
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@ -347,7 +347,11 @@ public:
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case 0xff04: timers_.write<4>(*value); break;
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case 0xff05: timers_.write<5>(*value); break;
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case 0xff06: video_.write<0xff06>(*value); break;
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case 0xff07: video_.write<0xff07>(*value); break;
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case 0xff07:
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video_.write<0xff07>(*value);
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update_audio();
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audio_.set_divider(*value);
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break;
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case 0xff08:
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// Observation here: the kernel posts a 0 to this
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// address upon completing each keyboard scan cycle,
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@ -398,7 +402,7 @@ public:
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case 0xff11:
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ff11_ = *value;
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update_audio();
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audio_.set_constrol(*value);
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audio_.set_control(*value);
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break;
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case 0xff12:
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ff12_ = *value & 0x3f;
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@ -540,7 +544,7 @@ private:
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Cycles time_since_audio_update_;
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Outputs::Speaker::PullLowpass<Audio> speaker_;
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void update_audio() {
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speaker_.run_for(audio_queue_, time_since_audio_update_.divide(Cycles(32)));
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speaker_.run_for(audio_queue_, time_since_audio_update_.flush<Cycles>());
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}
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// MARK: - MappedKeyboardMachine.
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