shithub: zelda3

ref: 540167a714a5f8f9c9335818801187baad91f1bc
dir: /snes/dsp.h/

#ifndef DSP_H
#define DSP_H

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>

#include "dsp_regs.h"
typedef struct Dsp Dsp;

#include "saveload.h"

typedef struct DspChannel {
  // pitch
  uint16_t pitch;
  uint16_t pitchCounter;
  bool pitchModulation;
  // brr decoding
  int16_t decodeBuffer[19]; // 16 samples per brr-block, +3 for interpolation
  uint8_t srcn;
  uint16_t decodeOffset;
  uint8_t previousFlags; // from last sample
  int16_t old;
  int16_t older;
  bool useNoise;
  // adsr, envelope, gain
  uint16_t adsrRates[4]; // attack, decay, sustain, gain
  uint16_t rateCounter;
  uint8_t adsrState; // 0: attack, 1: decay, 2: sustain, 3: gain, 4: release
  uint16_t sustainLevel;
  bool useGain;
  uint8_t gainMode;
  bool directGain;
  uint16_t gainValue; // for direct gain
  uint16_t gain;
  // keyon/off
  bool keyOn;
  bool keyOff;
  // output
  int16_t sampleOut; // final sample, to be multiplied by channel volume
  int8_t volumeL;
  int8_t volumeR;
  bool echoEnable;
} DspChannel;

struct Dsp {
  uint8_t *apu_ram;
  // mirror ram
  uint8_t ram[0x80];
  // 8 channels
  DspChannel channel[8];
  // overarching
  uint16_t dirPage;
  bool evenCycle;
  bool mute;
  bool reset;
  int8_t masterVolumeL;
  int8_t masterVolumeR;
  // noise
  int16_t noiseSample;
  uint16_t noiseRate;
  uint16_t noiseCounter;
  // echo
  bool echoWrites;
  int8_t echoVolumeL;
  int8_t echoVolumeR;
  int8_t feedbackVolume;
  uint16_t echoBufferAdr;
  uint16_t echoDelay;
  uint16_t echoRemain;
  uint16_t echoBufferIndex;
  uint8_t firBufferIndex;
  int8_t firValues[8];
  int16_t firBufferL[8];
  int16_t firBufferR[8];
  // sample buffer (1 frame at 32040 Hz: 534 samples, *2 for stereo)
  int16_t sampleBuffer[534 * 2];
  uint16_t sampleOffset; // current offset in samplebuffer
};


typedef struct DspRegWriteHistory {
  uint32_t count;
  uint8_t addr[256];
  uint8_t val[256];
} DspRegWriteHistory;

Dsp* dsp_init(uint8_t *apu_ram);
void dsp_free(Dsp* dsp);
void dsp_reset(Dsp* dsp);
void dsp_cycle(Dsp* dsp);
uint8_t dsp_read(Dsp* dsp, uint8_t adr);
void dsp_write(Dsp* dsp, uint8_t adr, uint8_t val);
void dsp_getSamples(Dsp* dsp, int16_t* sampleData, int samplesPerFrame, int numChannels);
void dsp_saveload(Dsp *dsp, SaveLoadFunc *func, void *ctx);

#endif