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gstreamer/gst/nsf/mmc5_snd.c
Tim-Philipp Müller 9e1b75fda3 Fix FSF address 
https://bugzilla.gnome.org/show_bug.cgi?id=687520
2012-11-04 00:09:59 +00:00

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/*
** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
**
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of version 2 of the GNU Library General
** Public License as published by the Free Software Foundation.
**
** 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
** Library General Public License for more details. To obtain a
** copy of the GNU Library General Public License, write to the Free
** Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** mmc5_snd.c
**
** Nintendo MMC5 sound emulation
** $Id$
*/
#include <string.h>
#include "types.h"
#include "mmc5_snd.h"
#include "nes_apu.h"
/* TODO: encapsulate apu/mmc5 rectangle */
#define APU_OVERSAMPLE
#define APU_VOLUME_DECAY(x) ((x) -= ((x) >> 7))
typedef struct mmc5dac_s
{
int32 output;
boolean enabled;
} mmc5dac_t;
/* look up table madness */
static int32 decay_lut[16];
static int vbl_lut[32];
/* various sound constants for sound emulation */
/* vblank length table used for rectangles, triangle, noise */
static const uint8 vbl_length[32] = {
5, 127, 10, 1, 19, 2, 40, 3, 80, 4, 30, 5, 7, 6, 13, 7,
6, 8, 12, 9, 24, 10, 48, 11, 96, 12, 36, 13, 8, 14, 16, 15
};
/* ratios of pos/neg pulse for rectangle waves
** 2/16 = 12.5%, 4/16 = 25%, 8/16 = 50%, 12/16 = 75%
** (4-bit adder in rectangles, hence the 16)
*/
static const int duty_lut[4] = {
2, 4, 8, 12
};
static int32 mmc5_incsize;
static uint8 mul[2];
static mmc5rectangle_t mmc5rect[2];
static mmc5dac_t mmc5dac;
#define MMC5_RECTANGLE_OUTPUT chan->output_vol
static int32
mmc5_rectangle (mmc5rectangle_t * chan)
{
int32 output;
#ifdef APU_OVERSAMPLE
int num_times;
int32 total;
#endif /* APU_OVERSAMPLE */
/* reg0: 0-3=volume, 4=envelope, 5=hold, 6-7=duty cycle
** reg1: 0-2=sweep shifts, 3=sweep inc/dec, 4-6=sweep length, 7=sweep on
** reg2: 8 bits of freq
** reg3: 0-2=high freq, 7-4=vbl length counter
*/
APU_VOLUME_DECAY (chan->output_vol);
if (FALSE == chan->enabled || 0 == chan->vbl_length)
return MMC5_RECTANGLE_OUTPUT;
/* vbl length counter */
if (FALSE == chan->holdnote)
chan->vbl_length--;
/* envelope decay at a rate of (env_delay + 1) / 240 secs */
chan->env_phase -= 4; /* 240/60 */
while (chan->env_phase < 0) {
chan->env_phase += chan->env_delay;
if (chan->holdnote)
chan->env_vol = (chan->env_vol + 1) & 0x0F;
else if (chan->env_vol < 0x0F)
chan->env_vol++;
}
if (chan->freq < APU_TO_FIXED (4))
return MMC5_RECTANGLE_OUTPUT;
chan->phaseacc -= mmc5_incsize; /* # of cycles per sample */
if (chan->phaseacc >= 0)
return MMC5_RECTANGLE_OUTPUT;
#ifdef APU_OVERSAMPLE
num_times = total = 0;
if (chan->fixed_envelope)
output = chan->volume << 8; /* fixed volume */
else
output = (chan->env_vol ^ 0x0F) << 8;
#endif
while (chan->phaseacc < 0) {
chan->phaseacc += chan->freq;
chan->adder = (chan->adder + 1) & 0x0F;
#ifdef APU_OVERSAMPLE
if (chan->adder < chan->duty_flip)
total += output;
else
total -= output;
num_times++;
#endif
}
#ifdef APU_OVERSAMPLE
chan->output_vol = total / num_times;
#else
if (chan->fixed_envelope)
output = chan->volume << 8; /* fixed volume */
else
output = (chan->env_vol ^ 0x0F) << 8;
if (0 == chan->adder)
chan->output_vol = output;
else if (chan->adder == chan->duty_flip)
chan->output_vol = -output;
#endif
return MMC5_RECTANGLE_OUTPUT;
}
static uint8
mmc5_read (uint32 address)
{
uint32 retval;
retval = (uint32) (mul[0] * mul[1]);
switch (address) {
case 0x5205:
return (uint8) retval;
case 0x5206:
return (uint8) (retval >> 8);
default:
return 0xFF;
}
}
/* mix vrcvi sound channels together */
static int32
mmc5_process (void)
{
int32 accum;
accum = mmc5_rectangle (&mmc5rect[0]);
accum += mmc5_rectangle (&mmc5rect[1]);
if (mmc5dac.enabled)
accum += mmc5dac.output;
return accum;
}
/* write to registers */
static void
mmc5_write (uint32 address, uint8 value)
{
int chan;
switch (address) {
/* rectangles */
case MMC5_WRA0:
case MMC5_WRB0:
chan = (address & 4) ? 1 : 0;
mmc5rect[chan].regs[0] = value;
mmc5rect[chan].volume = value & 0x0F;
mmc5rect[chan].env_delay = decay_lut[value & 0x0F];
mmc5rect[chan].holdnote = (value & 0x20) ? TRUE : FALSE;
mmc5rect[chan].fixed_envelope = (value & 0x10) ? TRUE : FALSE;
mmc5rect[chan].duty_flip = duty_lut[value >> 6];
break;
case MMC5_WRA1:
case MMC5_WRB1:
break;
case MMC5_WRA2:
case MMC5_WRB2:
chan = (address & 4) ? 1 : 0;
mmc5rect[chan].regs[2] = value;
if (mmc5rect[chan].enabled)
mmc5rect[chan].freq =
APU_TO_FIXED ((((mmc5rect[chan].regs[3] & 7) << 8) + value) + 1);
break;
case MMC5_WRA3:
case MMC5_WRB3:
chan = (address & 4) ? 1 : 0;
mmc5rect[chan].regs[3] = value;
if (mmc5rect[chan].enabled) {
mmc5rect[chan].vbl_length = vbl_lut[value >> 3];
mmc5rect[chan].env_vol = 0;
mmc5rect[chan].freq =
APU_TO_FIXED ((((value & 7) << 8) + mmc5rect[chan].regs[2]) + 1);
mmc5rect[chan].adder = 0;
}
break;
case MMC5_SMASK:
if (value & 0x01)
mmc5rect[0].enabled = TRUE;
else {
mmc5rect[0].enabled = FALSE;
mmc5rect[0].vbl_length = 0;
}
if (value & 0x02)
mmc5rect[1].enabled = TRUE;
else {
mmc5rect[1].enabled = FALSE;
mmc5rect[1].vbl_length = 0;
}
break;
case 0x5010:
if (value & 0x01)
mmc5dac.enabled = TRUE;
else
mmc5dac.enabled = FALSE;
break;
case 0x5011:
mmc5dac.output = (value ^ 0x80) << 8;
break;
case 0x5205:
mul[0] = value;
break;
case 0x5206:
mul[1] = value;
break;
default:
break;
}
}
/* reset state of vrcvi sound channels */
static void
mmc5_reset (void)
{
int i;
/* get the phase period from the apu */
mmc5_incsize = apu_getcyclerate ();
for (i = 0x5000; i < 0x5008; i++)
mmc5_write (i, 0);
mmc5_write (0x5010, 0);
mmc5_write (0x5011, 0);
}
static void
mmc5_init (void)
{
int i;
int num_samples = apu_getcontext ()->num_samples;
/* lut used for enveloping and frequency sweeps */
for (i = 0; i < 16; i++)
decay_lut[i] = num_samples * (i + 1);
/* used for note length, based on vblanks and size of audio buffer */
for (i = 0; i < 32; i++)
vbl_lut[i] = vbl_length[i] * num_samples;
}
/* TODO: bleh */
static void
mmc5_shutdown (void)
{
}
static apu_memread mmc5_memread[] = {
{0x5205, 0x5206, mmc5_read},
{(uint32) - 1, (uint32) - 1, NULL}
};
static apu_memwrite mmc5_memwrite[] = {
{0x5000, 0x5015, mmc5_write},
{0x5205, 0x5206, mmc5_write},
{(uint32) - 1, (uint32) - 1, NULL}
};
apuext_t mmc5_ext = {
mmc5_init,
mmc5_shutdown,
mmc5_reset,
mmc5_process,
mmc5_memread,
mmc5_memwrite
};
/*
** $Log$
** Revision 1.4 2008/03/26 07:40:55 slomo
** * gst/nsf/Makefile.am:
** * gst/nsf/fds_snd.c:
** * gst/nsf/mmc5_snd.c:
** * gst/nsf/nsf.c:
** * gst/nsf/types.h:
** * gst/nsf/vrc7_snd.c:
** * gst/nsf/vrcvisnd.c:
** * gst/nsf/memguard.c:
** * gst/nsf/memguard.h:
** Remove memguard again and apply hopefully all previously dropped
** local patches. Should be really better than the old version now.
**
** Revision 1.3 2008-03-25 15:56:11 slomo
** Patch by: Andreas Henriksson <andreas at fatal dot set>
** * gst/nsf/Makefile.am:
** * gst/nsf/dis6502.h:
** * gst/nsf/fds_snd.c:
** * gst/nsf/fds_snd.h:
** * gst/nsf/fmopl.c:
** * gst/nsf/fmopl.h:
** * gst/nsf/gstnsf.c:
** * gst/nsf/log.c:
** * gst/nsf/log.h:
** * gst/nsf/memguard.c:
** * gst/nsf/memguard.h:
** * gst/nsf/mmc5_snd.c:
** * gst/nsf/mmc5_snd.h:
** * gst/nsf/nes6502.c:
** * gst/nsf/nes6502.h:
** * gst/nsf/nes_apu.c:
** * gst/nsf/nes_apu.h:
** * gst/nsf/nsf.c:
** * gst/nsf/nsf.h:
** * gst/nsf/osd.h:
** * gst/nsf/types.h:
** * gst/nsf/vrc7_snd.c:
** * gst/nsf/vrc7_snd.h:
** * gst/nsf/vrcvisnd.c:
** * gst/nsf/vrcvisnd.h:
** Update our internal nosefart to nosefart-2.7-mls to fix segfaults
** on some files. Fixes bug #498237.
** Remove some // comments, fix some compiler warnings and use pow()
** instead of a slow, selfmade implementation.
**
** Revision 1.1 2003/04/08 20:53:01 ben
** Adding more files...
**
** Revision 1.6 2000/07/04 04:51:41 matt
** cleanups
**
** Revision 1.5 2000/07/03 02:18:53 matt
** much better external module exporting
**
** Revision 1.4 2000/06/28 22:03:51 matt
** fixed stupid oversight
**
** Revision 1.3 2000/06/20 20:46:58 matt
** minor cleanups
**
** Revision 1.2 2000/06/20 04:06:16 matt
** migrated external sound definition to apu module
**
** Revision 1.1 2000/06/20 00:06:47 matt
** initial revision
**
*/
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