Genesis-Plus-GX/source/sound/sound.c

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/***************************************************************************************
* Genesis Plus 1.2a
*
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 Charles Mac Donald (original code)
* modified by Eke-Eke (compatibility fixes & additional code), GC/Wii port
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Sound Hardware
****************************************************************************************/
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#include "shared.h"
#include "samplerate.h"
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/* generic functions */
int (*_YM2612_Write)(unsigned char adr, unsigned char data);
int (*_YM2612_Read)(void);
void (*_YM2612_Update)(int **buf, int length);
int (*_YM2612_Reset)(void);
/* cycle-accurate samples */
static double m68cycles_per_sample[2];
static double z80cycles_per_sample[2];
/* libsamplerate buffers (max. is 488 cycles per line x 313 lines / 144) */
static SRC_DATA src_data;
static float src_in[1061*2];
static int src_buffer[2][1061];
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/* YM2612 register arrays */
int fm_reg[2][0x100];
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/* return the number of samples that should have been rendered so far */
static inline uint32 fm_sample_cnt(uint8 is_z80)
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{
if (is_z80) return (uint32) ((double)(count_z80 + current_z80 - z80_ICount) / z80cycles_per_sample[0]);
else return (uint32) ((double) count_m68k / m68cycles_per_sample[0]);
}
static inline uint32 psg_sample_cnt(uint8 is_z80)
{
if (is_z80) return (uint32) ((double)(count_z80 + current_z80 - z80_ICount) / z80cycles_per_sample[1]);
else return (uint32) ((double) count_m68k / m68cycles_per_sample[1]);
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}
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/* update FM samples */
static inline void fm_update()
{
if(snd.fm.curStage - snd.fm.lastStage > 0)
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{
int *tempBuffer[2];
if (config.hq_fm && !config.fm_core)
{
tempBuffer[0] = src_buffer[0] + snd.fm.lastStage;
tempBuffer[1] = src_buffer[1] + snd.fm.lastStage;
}
else
{
tempBuffer[0] = snd.fm.buffer[0] + snd.fm.lastStage;
tempBuffer[1] = snd.fm.buffer[1] + snd.fm.lastStage;
}
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_YM2612_Update(tempBuffer, snd.fm.curStage - snd.fm.lastStage);
snd.fm.lastStage = snd.fm.curStage;
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}
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}
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/* update PSG samples */
static inline void psg_update()
{
if(snd.psg.curStage - snd.psg.lastStage > 0)
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{
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int16 *tempBuffer = snd.psg.buffer + snd.psg.lastStage;
SN76489_Update (0, tempBuffer, snd.psg.curStage - snd.psg.lastStage);
snd.psg.lastStage = snd.psg.curStage;
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}
}
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void sound_init(int rate)
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{
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double vclk = Master_Clock / 7.0; /* 68000 and YM2612 clock */
double zclk = Master_Clock / 15.0; /* Z80 and SN76489 clock */
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/* cycle-accurate FM samples */
if (config.hq_fm && !config.fm_core)
{
m68cycles_per_sample[0] = 144.0;
z80cycles_per_sample[0] = (144.0 * 7.0) / 15.0;
/* initialize samplerate converter data */
src_data.data_in = src_in;
src_data.data_out = snd.fm.src_out;
src_data.input_frames = (int)(((double)m68cycles_per_line * (double)lines_per_frame / 144.0) + 0.5);
src_data.output_frames = rate / vdp_rate;
src_data.src_ratio = (double)src_data.output_frames / (double)src_data.input_frames;
}
else
{
m68cycles_per_sample[0] = ((double)m68cycles_per_line * (double)lines_per_frame) / (double) (rate / vdp_rate);
z80cycles_per_sample[0] = ((double)z80cycles_per_line * (double)lines_per_frame) / (double) (rate / vdp_rate);
}
/* cycle-accurate PSG samples */
m68cycles_per_sample[1] = ((double)m68cycles_per_line * (double)lines_per_frame) / (double) (rate / vdp_rate);
z80cycles_per_sample[1] = ((double)z80cycles_per_line * (double)lines_per_frame) / (double) (rate / vdp_rate);
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/* initialize sound chips */
SN76489_Init(0, (int)zclk, rate);
SN76489_Config(0, MUTE_ALLON, VOL_FULL, FB_SEGAVDP, SRW_SEGAVDP, 0);
if (config.fm_core)
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{
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_YM2612_Write = YM2612_Write;
_YM2612_Read = YM2612_Read;
_YM2612_Update = YM2612_Update;
_YM2612_Reset = YM2612_Reset;
YM2612_Init((int)vclk, rate, config.hq_fm);
}
else
{
_YM2612_Write = YM2612Write;
_YM2612_Read = YM2612Read;
_YM2612_Update = YM2612UpdateOne;
_YM2612_Reset = YM2612ResetChip;
YM2612Init ((int)vclk, rate);
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}
}
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void sound_update(void)
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{
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/* finalize sound buffers */
snd.fm.curStage = (config.hq_fm && !config.fm_core) ? src_data.input_frames : snd.buffer_size;
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snd.psg.curStage = snd.buffer_size;
/* update last samples (if needed) */
fm_update();
psg_update();
/* Resampling */
if (config.hq_fm && !config.fm_core)
{
double scaled_value ;
int len = src_data.input_frames;
/* this is basically libsamplerate "src_int_to_float_array" function, adapted to interlace samples */
while (len)
{
len -- ;
src_in[len*2] = (float) (src_buffer[0] [len] / (8.0 * 0x10000000));
src_in[len*2 + 1] = (float) (src_buffer[1] [len] / (8.0 * 0x10000000));
}
/* samplerate conversion */
src_simple (&src_data, svp ? SRC_LINEAR : SRC_SINC_FASTEST, 2);
/* this is basically libsamplerate "src_float_to_int_array" function, adapted to interlace samples */
len = snd.buffer_size;
while (len)
{
len -- ;
scaled_value = snd.fm.src_out[len*2] * (8.0 * 0x10000000);
if (scaled_value >= (1.0 * 0x7FFFFFFF))
snd.fm.buffer[0][len] = 0x7fffffff;
else if (scaled_value <= (-8.0 * 0x10000000))
snd.fm.buffer[0][len] = -1 - 0x7fffffff;
else
snd.fm.buffer[0][len] = (long)scaled_value;
scaled_value = snd.fm.src_out[len*2+1] * (8.0 * 0x10000000);
if (scaled_value >= (1.0 * 0x7FFFFFFF))
snd.fm.buffer[1][len] = 0x7fffffff;
else if (scaled_value <= (-8.0 * 0x10000000))
snd.fm.buffer[1][len] = -1 - 0x7fffffff;
else
snd.fm.buffer[1][len] = (long)scaled_value;
}
}
/* reset samples count */
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snd.fm.curStage = 0;
snd.fm.lastStage = 0;
snd.psg.curStage = 0;
snd.psg.lastStage = 0;
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}
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/* YM2612 control */
/* restore FM registers */
void fm_restore(void)
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{
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int i;
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_YM2612_Reset();
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/* feed all the registers and update internal state */
for(i = 0; i < 0x100; i++)
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{
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_YM2612_Write(0, i);
_YM2612_Write(1, fm_reg[0][i]);
_YM2612_Write(2, i);
_YM2612_Write(3, fm_reg[1][i]);
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}
}
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/* write FM chip */
void fm_write(unsigned int cpu, unsigned int address, unsigned int data)
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{
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if (address & 1)
{
snd.fm.curStage = fm_sample_cnt(cpu);
fm_update();
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}
_YM2612_Write(address & 3, data);
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}
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/* read FM status */
unsigned int fm_read(unsigned int cpu, unsigned int address)
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{
snd.fm.curStage = fm_sample_cnt(cpu);
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fm_update();
return (_YM2612_Read() & 0xff);
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}
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/* PSG write */
void psg_write(unsigned int cpu, unsigned int data)
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{
snd.psg.curStage = psg_sample_cnt(cpu);
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psg_update();
SN76489_Write(0, data);
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}