path: root/gst/nsf/nsf.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., 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** nsf.c
**
** NSF loading/saving related functions
** $Id$
*/

#include <stdio.h>
#include <string.h>
#include "types.h"
#include "nsf.h"
#include "log.h"
#include "nes6502.h"
#include "nes_apu.h"
#include "vrcvisnd.h"
#include "vrc7_snd.h"
#include "mmc5_snd.h"
#include "fds_snd.h"

/* TODO: bleh! should encapsulate in NSF */
#define  MAX_ADDRESS_HANDLERS    32
static nes6502_memread nsf_readhandler[MAX_ADDRESS_HANDLERS];
static nes6502_memwrite nsf_writehandler[MAX_ADDRESS_HANDLERS];

static nsf_t *cur_nsf = NULL;

static void
nsf_setcontext (nsf_t * nsf)
{
  ASSERT (nsf);
  cur_nsf = nsf;
}

static uint8
read_mirrored_ram (uint32 address)
{
  return cur_nsf->cpu->mem_page[0][address & 0x7FF];
}

static void
write_mirrored_ram (uint32 address, uint8 value)
{
  cur_nsf->cpu->mem_page[0][address & 0x7FF] = value;
}

/* can be used for both banked and non-bankswitched NSFs */
static void
nsf_bankswitch (uint32 address, uint8 value)
{
  int cpu_page;
  uint8 *offset;

  cpu_page = address & 0x0F;
  offset = (cur_nsf->data - (cur_nsf->load_addr & 0x0FFF)) + (value << 12);

  nes6502_getcontext (cur_nsf->cpu);
  cur_nsf->cpu->mem_page[cpu_page] = offset;
  nes6502_setcontext (cur_nsf->cpu);
}

static nes6502_memread default_readhandler[] = {
  {0x0800, 0x1FFF, read_mirrored_ram},
  {0x4000, 0x4017, apu_read},
  {-1, -1, NULL}
};

static nes6502_memwrite default_writehandler[] = {
  {0x0800, 0x1FFF, write_mirrored_ram},
  {0x4000, 0x4017, apu_write},
  {0x5FF6, 0x5FFF, nsf_bankswitch},
  {-1, -1, NULL}
};

static uint8
invalid_read (uint32 address)
{
#ifdef NOFRENDO_DEBUG
  log_printf ("filthy NSF read from $%04X\n", address);
#endif /* NOFRENDO_DEBUG */

  return 0xFF;
}

static void
invalid_write (uint32 address, uint8 value)
{
#ifdef NOFRENDO_DEBUG
  log_printf ("filthy NSF tried to write $%02X to $%04X\n", value, address);
#endif /* NOFRENDO_DEBUG */
}

/* set up the address handlers that the CPU uses */
static void
build_address_handlers (nsf_t * nsf)
{
  int count, num_handlers;

  memset (nsf_readhandler, 0, sizeof (nsf_readhandler));
  memset (nsf_writehandler, 0, sizeof (nsf_writehandler));

  num_handlers = 0;
  for (count = 0; num_handlers < MAX_ADDRESS_HANDLERS; count++, num_handlers++) {
    if (NULL == default_readhandler[count].read_func)
      break;

    memcpy (&nsf_readhandler[num_handlers], &default_readhandler[count],
        sizeof (nes6502_memread));
  }

  if (nsf->apu->ext) {
    if (NULL != nsf->apu->ext->mem_read) {
      for (count = 0; num_handlers < MAX_ADDRESS_HANDLERS;
          count++, num_handlers++) {
        if (NULL == nsf->apu->ext->mem_read[count].read_func)
          break;

        memcpy (&nsf_readhandler[num_handlers], &nsf->apu->ext->mem_read[count],
            sizeof (nes6502_memread));
      }
    }
  }

  /* catch-all for bad reads */
  nsf_readhandler[num_handlers].min_range = 0x2000;     /* min address */
  nsf_readhandler[num_handlers].max_range = 0x5BFF;     /* max address */
  nsf_readhandler[num_handlers].read_func = invalid_read;       /* handler */
  num_handlers++;
  nsf_readhandler[num_handlers].min_range = -1;
  nsf_readhandler[num_handlers].max_range = -1;
  nsf_readhandler[num_handlers].read_func = NULL;
  num_handlers++;
  ASSERT (num_handlers <= MAX_ADDRESS_HANDLERS);

  num_handlers = 0;
  for (count = 0; num_handlers < MAX_ADDRESS_HANDLERS; count++, num_handlers++) {
    if (NULL == default_writehandler[count].write_func)
      break;

    memcpy (&nsf_writehandler[num_handlers], &default_writehandler[count],
        sizeof (nes6502_memwrite));
  }

  if (nsf->apu->ext) {
    if (NULL != nsf->apu->ext->mem_write) {
      for (count = 0; num_handlers < MAX_ADDRESS_HANDLERS;
          count++, num_handlers++) {
        if (NULL == nsf->apu->ext->mem_write[count].write_func)
          break;

        memcpy (&nsf_writehandler[num_handlers],
            &nsf->apu->ext->mem_write[count], sizeof (nes6502_memwrite));
      }
    }
  }

  /* catch-all for bad writes */
  nsf_writehandler[num_handlers].min_range = 0x2000;    /* min address */
  nsf_writehandler[num_handlers].max_range = 0x5BFF;    /* max address */
  nsf_writehandler[num_handlers].write_func = invalid_write;    /* handler */
  num_handlers++;
  /* protect region at $8000-$FFFF */
  nsf_writehandler[num_handlers].min_range = 0x8000;    /* min address */
  nsf_writehandler[num_handlers].max_range = 0xFFFF;    /* max address */
  nsf_writehandler[num_handlers].write_func = invalid_write;    /* handler */
  num_handlers++;
  nsf_writehandler[num_handlers].min_range = -1;
  nsf_writehandler[num_handlers].max_range = -1;
  nsf_writehandler[num_handlers].write_func = NULL;
  num_handlers++;
  ASSERT (num_handlers <= MAX_ADDRESS_HANDLERS);
}

#define  NSF_ROUTINE_LOC   0x5000

/* sets up a simple loop that calls the desired routine and spins */
static void
nsf_setup_routine (uint32 address, uint8 a_reg, uint8 x_reg)
{
  uint8 *mem;

  nes6502_getcontext (cur_nsf->cpu);
  mem =
      cur_nsf->cpu->mem_page[NSF_ROUTINE_LOC >> 12] +
      (NSF_ROUTINE_LOC & 0x0FFF);

  /* our lovely 4-byte 6502 NSF player */
  mem[0] = 0x20;                /* JSR address */
  mem[1] = address & 0xFF;
  mem[2] = address >> 8;
  mem[3] = 0xF2;                /* JAM (cpu kill op) */

  cur_nsf->cpu->pc_reg = NSF_ROUTINE_LOC;
  cur_nsf->cpu->a_reg = a_reg;
  cur_nsf->cpu->x_reg = x_reg;
  cur_nsf->cpu->y_reg = 0;
  cur_nsf->cpu->s_reg = 0xFF;

  nes6502_setcontext (cur_nsf->cpu);
}

/* retrieve any external soundchip driver */
static apuext_t *
nsf_getext (nsf_t * nsf)
{
  switch (nsf->ext_sound_type) {
    case EXT_SOUND_VRCVI:
      return &vrcvi_ext;

    case EXT_SOUND_VRCVII:
      return &vrc7_ext;

    case EXT_SOUND_FDS:
      return &fds_ext;

    case EXT_SOUND_MMC5:
      return &mmc5_ext;

    case EXT_SOUND_NAMCO106:
    case EXT_SOUND_SUNSOFT_FME07:
    case EXT_SOUND_NONE:
    default:
      return NULL;
  }
}

static void
nsf_inittune (nsf_t * nsf)
{
  uint8 bank, x_reg;
  uint8 start_bank, num_banks;

  memset (nsf->cpu->mem_page[0], 0, 0x800);
  memset (nsf->cpu->mem_page[6], 0, 0x1000);
  memset (nsf->cpu->mem_page[7], 0, 0x1000);

  if (nsf->bankswitched) {
    /* the first hack of the NSF spec! */
    if (EXT_SOUND_FDS == nsf->ext_sound_type) {
      nsf_bankswitch (0x5FF6, nsf->bankswitch_info[6]);
      nsf_bankswitch (0x5FF7, nsf->bankswitch_info[7]);
    }

    for (bank = 0; bank < 8; bank++)
      nsf_bankswitch (0x5FF8 + bank, nsf->bankswitch_info[bank]);
  } else {
    /* not bankswitched, just page in our standard stuff */
    ASSERT (nsf->load_addr + nsf->length <= 0x10000);

    /* avoid ripper filth */
    for (bank = 0; bank < 8; bank++)
      nsf_bankswitch (0x5FF8 + bank, bank);

    start_bank = nsf->load_addr >> 12;
    num_banks = ((nsf->load_addr + nsf->length - 1) >> 12) - start_bank + 1;

    for (bank = 0; bank < num_banks; bank++)
      nsf_bankswitch (0x5FF0 + start_bank + bank, bank);
  }

  /* determine PAL/NTSC compatibility shite */
  if (nsf->pal_ntsc_bits & NSF_DEDICATED_PAL)
    x_reg = 1;
  else
    x_reg = 0;

  /* execute 1 frame or so; let init routine run free */
  nsf_setup_routine (nsf->init_addr, (uint8) (nsf->current_song - 1), x_reg);
  nes6502_execute ((int) NES_FRAME_CYCLES);
}

void
nsf_frame (nsf_t * nsf)
{
  /* future expansion =) */
  /*nsf_setcontext(nsf); */

  /* one frame of NES processing */
  nsf_setup_routine (nsf->play_addr, 0, 0);
  nes6502_execute ((int) NES_FRAME_CYCLES);
}

/* Deallocate memory */
void
nes_shutdown (nsf_t * nsf)
{
  int i;
  void *mem;

  ASSERT (nsf);

  if (nsf->cpu) {
    if (nsf->cpu->mem_page[0])
      free (nsf->cpu->mem_page[0]);
    for (i = 5; i <= 7; i++) {
      if (nsf->cpu->mem_page[i])
        free (nsf->cpu->mem_page[i]);
    }
    mem = nsf->cpu;
    free (mem);
  }
}

void
nsf_init (void)
{
  nes6502_init ();
}

/* Initialize NES CPU, hardware, etc. */
static int
nsf_cpuinit (nsf_t * nsf)
{
  int i;

  nsf->cpu = malloc (sizeof (nes6502_context));
  if (NULL == nsf->cpu)
    return -1;

  memset (nsf->cpu, 0, sizeof (nes6502_context));

  nsf->cpu->mem_page[0] = malloc (0x800);
  if (NULL == nsf->cpu->mem_page[0])
    return -1;

  /* allocate some space for the NSF "player" MMC5 EXRAM, and WRAM */
  for (i = 5; i <= 7; i++) {
    nsf->cpu->mem_page[i] = malloc (0x1000);
    if (NULL == nsf->cpu->mem_page[i])
      return -1;
  }

  nsf->cpu->read_handler = nsf_readhandler;
  nsf->cpu->write_handler = nsf_writehandler;

  return 0;
}

static void
nsf_setup (nsf_t * nsf)
{
  int i;

  nsf->current_song = nsf->start_song;

  if (nsf->pal_ntsc_bits & NSF_DEDICATED_PAL) {
    if (nsf->pal_speed)
      nsf->playback_rate = 1000000 / nsf->pal_speed;
    else
      nsf->playback_rate = 50;  /* 50 Hz */
  } else {
    if (nsf->ntsc_speed)
      nsf->playback_rate = 1000000 / nsf->ntsc_speed;
    else
      nsf->playback_rate = 60;  /* 60 Hz */
  }

  nsf->bankswitched = FALSE;

  for (i = 0; i < 8; i++) {
    if (nsf->bankswitch_info[i]) {
      nsf->bankswitched = TRUE;
      break;
    }
  }
}

#ifdef HOST_LITTLE_ENDIAN
#define  SWAP_16(x)  (x)
#else /* !HOST_LITTLE_ENDIAN */
#define  SWAP_16(x)  (((uint16) x >> 8) | (((uint16) x & 0xFF) << 8))
#endif /* !HOST_LITTLE_ENDIAN */

/* Load a ROM image into memory */
nsf_t *
nsf_load (char *filename, void *source, int length)
{
  FILE *fp = NULL;
  char *new_fn = NULL;
  nsf_t *temp_nsf;

  if (NULL == filename && NULL == source)
    return NULL;

  if (NULL == source) {
    fp = fopen (filename, "rb");

    /* Didn't find the file?  Maybe the .NSF extension was omitted */
    if (NULL == fp) {
      new_fn = malloc (strlen (filename) + 5);
      if (NULL == new_fn)
        return NULL;
      strcpy (new_fn, filename);

      if (NULL == strrchr (new_fn, '.'))
        strcat (new_fn, ".nsf");

      fp = fopen (new_fn, "rb");

      if (NULL == fp) {
        void *t = new_fn;

        log_printf ("could not find file '%s'\n", new_fn);
        free (t);
        return NULL;
      }
    }
  }

  temp_nsf = malloc (sizeof (nsf_t));
  if (NULL == temp_nsf)
    return NULL;

  /* Read in the header */
  if (NULL == source) {
    if (fread (temp_nsf, 1, NSF_HEADER_SIZE, fp) != NSF_HEADER_SIZE) {
      log_printf ("error reading file\n");
      free (temp_nsf);
      return NULL;
    }
  } else
    memcpy (temp_nsf, source, NSF_HEADER_SIZE);

  if (memcmp (temp_nsf->id, NSF_MAGIC, 5)) {
    if (NULL == source) {
      void *t = new_fn;

      log_printf ("%s is not an NSF format file\n", new_fn);
      fclose (fp);
      free (t);
    }
    nsf_free (&temp_nsf);
    return NULL;
  }

  /* fixup endianness */
  temp_nsf->load_addr = SWAP_16 (temp_nsf->load_addr);
  temp_nsf->init_addr = SWAP_16 (temp_nsf->init_addr);
  temp_nsf->play_addr = SWAP_16 (temp_nsf->play_addr);
  temp_nsf->ntsc_speed = SWAP_16 (temp_nsf->ntsc_speed);
  temp_nsf->pal_speed = SWAP_16 (temp_nsf->pal_speed);

  /* we're now at position 80h */
  if (NULL == source) {
    fseek (fp, 0, SEEK_END);
    temp_nsf->length = ftell (fp) - NSF_HEADER_SIZE;
  } else {
    temp_nsf->length = length - NSF_HEADER_SIZE;
  }

  /* Allocate NSF space, and load it up! */
  temp_nsf->data = malloc (temp_nsf->length);
  if (NULL == temp_nsf->data) {
    log_printf ("error allocating memory for NSF data\n");
    nsf_free (&temp_nsf);
    return NULL;
  }

  /* seek to end of header, read in data */
  if (NULL == source) {
    fseek (fp, NSF_HEADER_SIZE, SEEK_SET);
    if (fread (temp_nsf->data, temp_nsf->length, 1, fp) < 0)
      log_printf ("error reading end of header\n");

    fclose (fp);


    if (new_fn) {
      void *t = new_fn;

      free (t);
    }
  } else
    memcpy (temp_nsf->data, (uint8 *) source + NSF_HEADER_SIZE,
        temp_nsf->length);

  /* Set up some variables */
  nsf_setup (temp_nsf);

  temp_nsf->apu = NULL;         /* just make sure */

  if (nsf_cpuinit (temp_nsf)) {
    nsf_free (&temp_nsf);
    return NULL;
  }

  return temp_nsf;
}

/* Free an NSF */
void
nsf_free (nsf_t ** nsf)
{
  if (*nsf) {
    if ((*nsf)->apu)
      apu_destroy ((*nsf)->apu);

    nes_shutdown (*nsf);

    if ((*nsf)->data) {
      void *mem = (*nsf)->data;

      free (mem);
    }

    free (*nsf);
  }
}

void
nsf_setchan (nsf_t * nsf, int chan, boolean enabled)
{
  if (nsf) {
    nsf_setcontext (nsf);
    apu_setchan (chan, enabled);
  }
}

void
nsf_playtrack (nsf_t * nsf, int track, int sample_rate, int sample_bits,
    boolean stereo)
{
  ASSERT (nsf);

  /* make this NSF the current context */
  nsf_setcontext (nsf);

  /* create the APU */
  if (nsf->apu)
    apu_destroy (nsf->apu);

  nsf->apu = apu_create (sample_rate, nsf->playback_rate, sample_bits, stereo);
  if (NULL == nsf->apu) {
    nsf_free (&nsf);
    return;
  }

  apu_setext (nsf->apu, nsf_getext (nsf));

  /* go ahead and init all the read/write handlers */
  build_address_handlers (nsf);

  /* convenience? */
  nsf->process = nsf->apu->process;

  nes6502_setcontext (nsf->cpu);

  if (track > nsf->num_songs)
    track = nsf->num_songs;
  else if (track < 1)
    track = 1;

  nsf->current_song = track;

  apu_reset ();

  nsf_inittune (nsf);
}

void
nsf_setfilter (nsf_t * nsf, int filter_type)
{
  if (nsf) {
    nsf_setcontext (nsf);
    apu_setfilter (filter_type);
  }
}

/*
** $Log$
** Revision 1.2  2006/07/18 09:36:46  wtay
** * gst/nsf/nsf.c: (nsf_load):
** Fix compilation by not ignoring return values of fread.
**
** Revision 1.1  2006/07/13 15:07:28  wtay
** Based on patches by: Johan Dahlin <johan at gnome dot org>
** Ronald Bultje <rbultje at ronald dot bitfreak dot net>
** * configure.ac:
** * 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/gstnsf.h:
** * 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:
** Added NSF decoder plugin. Fixes 151192.
**
** Revision 1.14  2000/07/05 14:54:45  matt
** fix for naughty Crystalis rip
**
** Revision 1.13  2000/07/04 04:59:38  matt
** removed DOS-specific stuff, fixed bug in address handlers
**
** Revision 1.12  2000/07/03 02:19:36  matt
** dynamic address range handlers, cleaner and faster
**
** Revision 1.11  2000/06/23 03:27:58  matt
** cleaned up external sound inteface
**
** Revision 1.10  2000/06/20 20:42:47  matt
** accuracy changes
**
** Revision 1.9  2000/06/20 00:05:58  matt
** changed to driver-based external sound generation
**
** Revision 1.8  2000/06/13 03:51:54  matt
** update API to take freq/sample data on nsf_playtrack
**
** Revision 1.7  2000/06/12 03:57:14  matt
** more robust checking for winamp plugin
**
** Revision 1.6  2000/06/12 01:13:00  matt
** added CPU/APU as members of the nsf struct
**
** Revision 1.5  2000/06/11 16:09:21  matt
** nsf_free is more robust
**
** Revision 1.4  2000/06/09 15:12:26  matt
** initial revision
**
*/