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Diffstat (limited to 'contrib/nosefart/vrcvisnd.c')
| -rw-r--r-- | contrib/nosefart/vrcvisnd.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/contrib/nosefart/vrcvisnd.c b/contrib/nosefart/vrcvisnd.c new file mode 100644 index 000000000..b1f26fe52 --- /dev/null +++ b/contrib/nosefart/vrcvisnd.c @@ -0,0 +1,210 @@ +/* +** 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. +** +** +** vrcvisnd.c +** +** VRCVI sound hardware emulation +** $Id: vrcvisnd.c,v 1.2 2003/12/05 15:55:01 f1rmb Exp $ +*/ + +#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 }, + { -1, -1, NULL } +}; + +apuext_t vrcvi_ext = +{ + vrcvi_dummy, /* no init */ + vrcvi_dummy, /* no shutdown */ + vrcvi_reset, + vrcvi_process, + NULL, /* no reads */ + vrcvi_memwrite +}; + +/* +** $Log: vrcvisnd.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 07:04:36 tmmm +** initial import of Nosefart sources +** +** 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 +** +*/ |