gstreamer/gst/nsf/vrcvisnd.c
2012-11-04 00:09:59 +00:00

258 lines
6.4 KiB
C

/*
** 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.
**
**
** vrcvisnd.c
**
** VRCVI sound hardware emulation
** $Id$
*/
#include <stdio.h>
#include "types.h"
#include "vrcvisnd.h"
#include "nes_apu.h"
static vrcvisnd_t vrcvi;
static int32 vrcvi_incsize;
/* VRCVI rectangle wave generation */
static int32
vrcvi_rectangle (vrcvirectangle_t * chan)
{
/* reg0: 0-3=volume, 4-6=duty cycle
** reg1: 8 bits of freq
** reg2: 0-3=high freq, 7=enable
*/
chan->phaseacc -= vrcvi_incsize; /* # of clocks per wave cycle */
while (chan->phaseacc < 0) {
chan->phaseacc += chan->freq;
chan->adder = (chan->adder + 1) & 0x0F;
}
/* return if not enabled */
if (FALSE == chan->enabled)
return 0;
if (chan->adder < chan->duty_flip)
return -(chan->volume);
else
return chan->volume;
}
/* VRCVI sawtooth wave generation */
static int32
vrcvi_sawtooth (vrcvisawtooth_t * chan)
{
/* reg0: 0-5=phase accumulator bits
** reg1: 8 bits of freq
** reg2: 0-3=high freq, 7=enable
*/
chan->phaseacc -= vrcvi_incsize; /* # of clocks per wav cycle */
while (chan->phaseacc < 0) {
chan->phaseacc += chan->freq;
chan->output_acc += chan->volume;
if (7 == ++chan->adder) {
chan->adder = 0;
chan->output_acc = 0;
}
}
/* return if not enabled */
if (FALSE == chan->enabled)
return 0;
else
return (chan->output_acc >> 3) << 9;
}
/* mix vrcvi sound channels together */
static int32
vrcvi_process (void)
{
int32 output;
output = vrcvi_rectangle (&vrcvi.rectangle[0]);
output += vrcvi_rectangle (&vrcvi.rectangle[1]);
output += vrcvi_sawtooth (&vrcvi.saw);
return output;
}
/* write to registers */
static void
vrcvi_write (uint32 address, uint8 value)
{
int chan;
switch (address & 0xB003) {
case 0x9000:
case 0xA000:
chan = (address >> 12) - 9;
vrcvi.rectangle[chan].reg[0] = value;
vrcvi.rectangle[chan].volume = (value & 0x0F) << 8;
vrcvi.rectangle[chan].duty_flip = (value >> 4) + 1;
break;
case 0x9001:
case 0xA001:
chan = (address >> 12) - 9;
vrcvi.rectangle[chan].reg[1] = value;
vrcvi.rectangle[chan].freq =
APU_TO_FIXED (((vrcvi.rectangle[chan].reg[2] & 0x0F) << 8) + value +
1);
break;
case 0x9002:
case 0xA002:
chan = (address >> 12) - 9;
vrcvi.rectangle[chan].reg[2] = value;
vrcvi.rectangle[chan].freq =
APU_TO_FIXED (((value & 0x0F) << 8) + vrcvi.rectangle[chan].reg[1] +
1);
vrcvi.rectangle[chan].enabled = (value & 0x80) ? TRUE : FALSE;
break;
case 0xB000:
vrcvi.saw.reg[0] = value;
vrcvi.saw.volume = value & 0x3F;
break;
case 0xB001:
vrcvi.saw.reg[1] = value;
vrcvi.saw.freq =
APU_TO_FIXED ((((vrcvi.saw.reg[2] & 0x0F) << 8) + value + 1) << 1);
break;
case 0xB002:
vrcvi.saw.reg[2] = value;
vrcvi.saw.freq =
APU_TO_FIXED ((((value & 0x0F) << 8) + vrcvi.saw.reg[1] + 1) << 1);
vrcvi.saw.enabled = (value & 0x80) ? TRUE : FALSE;
break;
default:
break;
}
}
/* reset state of vrcvi sound channels */
static void
vrcvi_reset (void)
{
int i;
/* preload regs */
for (i = 0; i < 3; i++) {
vrcvi_write (0x9000 + i, 0);
vrcvi_write (0xA000 + i, 0);
vrcvi_write (0xB000 + i, 0);
}
/* get the phase period from the apu */
vrcvi_incsize = apu_getcyclerate ();
}
static void
vrcvi_dummy (void)
{
}
static apu_memwrite vrcvi_memwrite[] = {
/* { 0x4040, 0x4092, ext_write }, *//* FDS sound regs */
{0x9000, 0x9002, vrcvi_write}, /* vrc6 */
{0xA000, 0xA002, vrcvi_write},
{0xB000, 0xB002, vrcvi_write},
{(uint32) - 1, (uint32) - 1, NULL}
};
apuext_t vrcvi_ext = {
vrcvi_dummy, /* no init */
vrcvi_dummy, /* no shutdown */
vrcvi_reset,
vrcvi_process,
NULL, /* no reads */
vrcvi_memwrite
};
/*
** $Log$
** Revision 1.4 2008/03/26 07:40:56 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 15:56:13 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 1.9 2000/07/04 04:51:41 matt
** cleanups
**
** Revision 1.8 2000/07/03 02:18:53 matt
** much better external module exporting
**
** Revision 1.7 2000/06/20 04:06:16 matt
** migrated external sound definition to apu module
**
** Revision 1.6 2000/06/20 00:08:58 matt
** changed to driver based API
**
** Revision 1.5 2000/06/09 16:49:02 matt
** removed all floating point from sound generation
**
** Revision 1.4 2000/06/09 15:12:28 matt
** initial revision
**
*/