/*
** 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.
**
**
** map64.c
**
** mapper 64 interface
** $Id: map064.c,v 1.2 2001/04/27 14:37:11 neil Exp $
*/

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

static struct
{
   int counter, latch;
   bool enabled, reset;
} irq;

static uint8 command = 0;
static uint16 vrombase = 0x0000;

static void map64_hblank(int vblank)
{
   if (vblank)
      return;

   irq.reset = false;

   if (ppu_enabled())
   {
      if (0 == irq.counter--)
      {
         irq.counter = irq.latch;
       
         if (true == irq.enabled)
            nes_irq();

         irq.reset = true;
      }
   }
}

/* mapper 64: Tengen RAMBO-1 */
static void map64_write(uint32 address, uint8 value)
{
   switch (address & 0xE001)
   {
   case 0x8000:
      command = value;
      vrombase = (value & 0x80) ? 0x1000 : 0x0000;
      break;

   case 0x8001:
      switch (command & 0xF)
      {
      case 0:
         mmc_bankvrom(1, 0x0000 ^ vrombase, value);
         mmc_bankvrom(1, 0x0400 ^ vrombase, value);
         break;

      case 1:
         mmc_bankvrom(1, 0x0800 ^ vrombase, value);
         mmc_bankvrom(1, 0x0C00 ^ vrombase, value);
         break;

      case 2:
         mmc_bankvrom(1, 0x1000 ^ vrombase, value);
         break;

      case 3:
         mmc_bankvrom(1, 0x1400 ^ vrombase, value);
         break;

      case 4:
         mmc_bankvrom(1, 0x1800 ^ vrombase, value);
         break;

      case 5:
         mmc_bankvrom(1, 0x1C00 ^ vrombase, value);
         break;

      case 6:
         mmc_bankrom(8, (command & 0x40) ? 0xA000 : 0x8000, value);
         break;

      case 7:
         mmc_bankrom(8, (command & 0x40) ? 0xC000 : 0xA000, value);
         break;

      case 8:
         mmc_bankvrom(1, 0x0400, value);
         break;

      case 9:
         mmc_bankvrom(1, 0x0C00, value);
         break;

      case 15:
         mmc_bankrom(8, (command & 0x40) ? 0x8000 : 0xC000, value);
         break;

      default:
#ifdef NOFRENDO_DEBUG
         log_printf("mapper 64: unknown command #%d", command & 0xF);
#endif
         break;
      }
      break;
   
   case 0xA000:
      if (value & 1)
         ppu_mirror(0, 0, 1, 1);
      else
         ppu_mirror(0, 1, 0, 1);
      break;
   
   case 0xC000:
      //irq.counter = value;
      irq.latch = value;
      break;
   
   case 0xC001:
      //irq.latch = value;
      irq.reset = true;
      break;
   
   case 0xE000:
      //irq.counter = irq.latch;
      irq.enabled = false;
      break;
   
   case 0xE001:
      irq.enabled = true;
      break;
   
   default:
#ifdef NOFRENDO_DEBUG
      log_printf("mapper 64: Wrote $%02X to $%04X", value, address);
#endif
      break;
   }

   if (true == irq.reset)
      irq.counter = irq.latch;
}

static void map64_init(void)
{
   mmc_bankrom(8, 0x8000, MMC_LASTBANK);
   mmc_bankrom(8, 0xA000, MMC_LASTBANK);
   mmc_bankrom(8, 0xC000, MMC_LASTBANK);
   mmc_bankrom(8, 0xE000, MMC_LASTBANK);

   irq.counter = irq.latch = 0;
   irq.reset = irq.enabled = false;
}

static map_memwrite map64_memwrite[] =
{
   { 0x8000, 0xFFFF, map64_write },
   {     -1,     -1, NULL }
};

mapintf_t map64_intf =
{
   64, /* mapper number */
   "Tengen RAMBO-1", /* mapper name */
   map64_init, /* init routine */
   NULL, /* vblank callback */
   map64_hblank, /* hblank callback */
   NULL, /* get state (snss) */
   NULL, /* set state (snss) */
   NULL, /* memory read structure */
   map64_memwrite, /* memory write structure */
   NULL /* external sound device */
};

/*
** $Log: map064.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 1.1.1.1  2001/04/27 07:03:54  neil
** initial
**
** Revision 1.1  2000/10/24 12:19:33  matt
** changed directory structure
**
** Revision 1.8  2000/10/22 19:17:46  matt
** mapper cleanups galore
**
** Revision 1.7  2000/10/22 15:03:13  matt
** simplified mirroring
**
** Revision 1.6  2000/10/21 19:33:38  matt
** many more cleanups
**
** Revision 1.5  2000/10/10 13:58:17  matt
** stroustrup squeezing his way in the door
**
** Revision 1.4  2000/07/10 13:51:25  matt
** using generic nes_irq() routine now
**
** Revision 1.3  2000/07/10 05:29:03  matt
** cleaned up some mirroring issues
**
** Revision 1.2  2000/07/06 02:48:43  matt
** clearly labelled structure members
**
** Revision 1.1  2000/07/05 05:05:18  matt
** initial revision
**
*/