Genesis-Plus-GX/source/sound/sn76489.h

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2007-08-10 22:34:06 +02:00
#ifndef _SN76489_H_
#define _SN76489_H_
#define MAX_SN76489 4
#include "shared.h"
/*
More testing is needed to find and confirm feedback patterns for
SN76489 variants and compatible chips.
*/
enum feedback_patterns {
FB_BBCMICRO = 0x8005, /* Texas Instruments TMS SN76489N (original) from BBC Micro computer */
FB_SC3000 = 0x0006, /* Texas Instruments TMS SN76489AN (rev. A) from SC-3000H computer */
FB_SEGAVDP = 0x0009, /* SN76489 clone in Sega's VDP chips (315-5124, 315-5246, 315-5313, Game Gear) */
};
enum sr_widths {
SRW_SC3000BBCMICRO = 15,
SRW_SEGAVDP = 16
};
enum volume_modes {
VOL_TRUNC = 0, /* Volume levels 13-15 are identical */
VOL_FULL = 1, /* Volume levels 13-15 are unique */
};
enum mute_values {
MUTE_ALLOFF = 0, /* All channels muted */
MUTE_TONE1 = 1, /* Tone 1 mute control */
MUTE_TONE2 = 2, /* Tone 2 mute control */
MUTE_TONE3 = 4, /* Tone 3 mute control */
MUTE_NOISE = 8, /* Noise mute control */
MUTE_ALLON = 15, /* All channels enabled */
};
typedef struct
{
int Mute; // per-channel muting
int VolumeArray;
int BoostNoise; // double noise volume when non-zero
/* Variables */
float Clock;
float dClock;
int PSGStereo;
int NumClocksForSample;
int WhiteNoiseFeedback;
int SRWidth;
/* PSG registers: */
int Registers[8]; /* Tone, vol x4 */
int LatchedRegister;
int NoiseShiftRegister;
int NoiseFreq; /* Noise channel signal generator frequency */
/* Output calculation variables */
int ToneFreqVals[4]; /* Frequency register values (counters) */
int ToneFreqPos[4]; /* Frequency channel flip-flops */
int Channels[4]; /* Value of each channel, before stereo is applied */
float IntermediatePos[4]; /* intermediate values used at boundaries between + and - (does not need double accuracy)*/
int panning[4]; /* fake stereo - 0..127..254 */
} SN76489_Context;
/* Function prototypes */
void SN76489_Init(int which, int PSGClockValue, int SamplingRate);
void SN76489_Reset(int which);
void SN76489_Shutdown(void);
void SN76489_Config(int which, int mute, int volume, int feedback, int sw_width, int boost_noise);
void SN76489_SetContext(int which, uint8 *data);
void SN76489_GetContext(int which, uint8 *data);
uint8 *SN76489_GetContextPtr(int which);
int SN76489_GetContextSize(void);
void SN76489_Write(int which, int data);
/*void SN76489_GGStereoWrite(int which, int data);*/
void SN76489_Update(int which, INT16 *buffer, int length);
/* Non-standard getters and setters */
int SN76489_GetMute(int which);
void SN76489_SetMute(int which, int val);
int SN76489_GetVolType(int which);
void SN76489_SetVolType(int which, int val);
void SN76489_SetPanning(int which, int ch0, int ch1, int ch2, int ch3);
/* and a non-standard data getter */
/*void SN76489_UpdateOne(int which, int *l, int *r);*/
#endif /* _SN76489_H_ */