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CLK/Machines/Apple/AppleIIgs/Sound.hpp
2020-12-09 19:46:32 -05:00

112 lines
3.1 KiB
C++

//
// Sound.hpp
// Clock Signal
//
// Created by Thomas Harte on 04/11/2020.
// Copyright © 2020 Thomas Harte. All rights reserved.
//
#ifndef Apple_IIgs_Sound_hpp
#define Apple_IIgs_Sound_hpp
#include <atomic>
#include "../../../ClockReceiver/ClockReceiver.hpp"
#include "../../../Concurrency/AsyncTaskQueue.hpp"
#include "../../../Outputs/Speaker/Implementation/SampleSource.hpp"
namespace Apple {
namespace IIgs {
namespace Sound {
class GLU: public Outputs::Speaker::SampleSource {
public:
GLU(Concurrency::DeferringAsyncTaskQueue &audio_queue);
void set_control(uint8_t);
uint8_t get_control();
void set_data(uint8_t);
uint8_t get_data();
void set_address_low(uint8_t);
uint8_t get_address_low();
void set_address_high(uint8_t);
uint8_t get_address_high();
void run_for(Cycles);
Cycles get_next_sequence_point() const;
bool get_interrupt_line();
// SampleSource.
void get_samples(std::size_t number_of_samples, std::int16_t *target);
void set_sample_volume_range(std::int16_t range);
void skip_samples(const std::size_t number_of_samples);
private:
Concurrency::DeferringAsyncTaskQueue &audio_queue_;
uint16_t address_ = 0;
// Use a circular buffer for piping memory alterations onto the audio
// thread; it would be prohibitive to defer every write individually.
//
// Assumed: on most modern architectures, an atomic 64-bit read or
// write can be achieved locklessly.
struct MemoryWrite {
uint32_t time;
uint16_t address;
uint8_t value;
bool enabled;
};
static_assert(sizeof(MemoryWrite) == 8);
constexpr static int StoreBufferSize = 16384;
std::atomic<MemoryWrite> pending_stores_[StoreBufferSize];
uint32_t pending_store_read_ = 0, pending_store_read_time_ = 0;
uint32_t pending_store_write_ = 0, pending_store_write_time_ = 0;
// Maintain state both 'locally' (i.e. on the emulation thread) and
// 'remotely' (i.e. on the audio thread).
struct EnsoniqState {
uint8_t ram_[65536];
struct Oscillator {
uint32_t position;
// Programmer-set values.
uint16_t velocity;
uint8_t volume;
uint8_t address;
uint8_t control;
uint8_t table_size;
// Derived state.
uint32_t overflow_mask; // If a non-zero bit gets anywhere into the overflow mask, this channel
// has wrapped around. It's a function of table_size.
bool interrupt_request = false; // Will be non-zero if this channel would request an interrupt, were
// it currently enabled to do so.
uint8_t sample(uint8_t *ram);
int16_t output(uint8_t *ram);
} oscillators[32];
// Some of these aren't actually needed on both threads.
uint8_t control = 0;
int oscillator_count = 1;
void set_register(uint16_t address, uint8_t value);
} local_, remote_;
// Functions to update an EnsoniqState; these don't belong to the state itself
// because they also access the pending stores (inter alia).
void generate_audio(size_t number_of_samples, std::int16_t *target);
void skip_audio(EnsoniqState &state, size_t number_of_samples);
// Audio-thread state.
int16_t output_range_ = 0;
};
}
}
}
#endif /* SoundGLU_hpp */