summaryrefslogtreecommitdiff
path: root/contrib/nosefart/mmc5_snd.c
diff options
context:
space:
mode:
Diffstat (limited to 'contrib/nosefart/mmc5_snd.c')
-rw-r--r--contrib/nosefart/mmc5_snd.c360
1 files changed, 360 insertions, 0 deletions
diff --git a/contrib/nosefart/mmc5_snd.c b/contrib/nosefart/mmc5_snd.c
new file mode 100644
index 000000000..7269fa967
--- /dev/null
+++ b/contrib/nosefart/mmc5_snd.c
@@ -0,0 +1,360 @@
+/*
+** 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+**
+** Any permitted reproduction of these routines, in whole or in part,
+** must bear this legend.
+**
+**
+** mmc5_snd.c
+**
+** Nintendo MMC5 sound emulation
+** $Id: mmc5_snd.c,v 1.2 2003/12/05 15:55:01 f1rmb Exp $
+*/
+
+#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 },
+ { -1, -1, NULL }
+};
+
+static apu_memwrite mmc5_memwrite[] =
+{
+ { 0x5000, 0x5015, mmc5_write },
+ { 0x5205, 0x5206, mmc5_write },
+ { -1, -1, NULL }
+};
+
+apuext_t mmc5_ext =
+{
+ mmc5_init,
+ mmc5_shutdown,
+ mmc5_reset,
+ mmc5_process,
+ mmc5_memread,
+ mmc5_memwrite
+};
+
+/*
+** $Log: mmc5_snd.c,v $
+** Revision 1.2 2003/12/05 15:55:01 f1rmb
+** cleanup phase II. use xprintf when it's relevant, use xine_xmalloc when it's relevant too. Small other little fix (can't remember). Change few internal function prototype because it xine_t pointer need to be used if some xine's internal sections. NOTE: libdvd{nav,read} is still too noisy, i will take a look to made it quit, without invasive changes. To be continued...
+**
+** Revision 1.1 2003/01/08 07:04:35 tmmm
+** initial import of Nosefart sources
+**
+** 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
+**
+*/
generated by cgit v1.2.3 (git 2.25.1) at 2025-04-25 18:10:44 +0000