map229.c 3.11 KB
/*
** 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.
**
**
** map229.c
**
** Mapper #229 (31 in 1)
** Implementation by Firebug
** Mapper information courtesy of Mark Knibbs
** $Id: map229.c,v 1.2 2001/04/27 14:37:11 neil Exp $
**
*/

#include <noftypes.h>
#include <nes_mmc.h>
#include <nes.h>
#include <libsnss.h>
#include <log.h>

/************************/
/* Mapper #229: 31 in 1 */
/************************/
static void map229_init (void)
{
  /* On reset, PRG is set to first 32K and CHR to first 8K */
  mmc_bankrom (32, 0x8000, 0x00);
  mmc_bankvrom (8, 0x0000, 0x00);

  /* Done */
  return;
}

/*******************************************/
/* Mapper #229 write handler ($8000-$FFFF) */
/*******************************************/
static void map229_write (uint32 address, uint8 value)
{
  /* Value written is irrelevant */
  UNUSED (value);

  /* A4-A0 sets 8K CHR page */
  mmc_bankvrom (8, 0x0000, (uint8) (address & 0x1F));

  /* If A4-A1 are all low then select the first 32K,     */
  /* otherwise select a 16K bank at both $8000 and $C000 */
  if ((address & 0x1E) == 0x00)
  {
    mmc_bankrom (32, 0x8000, 0x00);
  }
  else
  {
    mmc_bankrom (16, 0x8000, (uint8) (address & 0x1F));
    mmc_bankrom (16, 0xC000, (uint8) (address & 0x1F));
  }

  /* A5: mirroring (low = vertical, high = horizontal) */
  if (address & 0x20) ppu_mirror(0, 0, 1, 1);
  else                ppu_mirror(0, 1, 0, 1);

  /* Done */
  return;
}

static map_memwrite map229_memwrite [] =
{
   { 0x8000, 0xFFFF, map229_write },
   {     -1,     -1, NULL }
};

mapintf_t map229_intf =
{
   229,                              /* Mapper number */
   "31 in 1 (bootleg)",              /* Mapper name */
   map229_init,                      /* Initialization routine */
   NULL,                             /* VBlank callback */
   NULL,                             /* HBlank callback */
   NULL,                             /* Get state (SNSS) */
   NULL,                             /* Set state (SNSS) */
   NULL,                             /* Memory read structure */
   map229_memwrite,                  /* Memory write structure */
   NULL                              /* External sound device */
};

/*
** $Log: map229.c,v $
** Revision 1.2  2001/04/27 14:37:11  neil
** wheeee
**
** Revision 1.1  2001/04/27 12:54:40  neil
** blah
**
** Revision 1.1  2001/04/27 10:57:41  neil
** wheee
**
** Revision 1.1  2000/12/30 06:34:31  firebug
** Initial revision
**
**
*/