1  /*
  2  ** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
  3  **
  4  **
  5  ** This program is free software; you can redistribute it and/or
  6  ** modify it under the terms of version 2 of the GNU Library General 
  7  ** Public License as published by the Free Software Foundation.
  8  **
  9  ** This program is distributed in the hope that it will be useful, 
 10  ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 11  ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
 12  ** Library General Public License for more details.  To obtain a 
 13  ** copy of the GNU Library General Public License, write to the Free 
 14  ** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 15  **
 16  ** Any permitted reproduction of these routines, in whole or in part,
 17  ** must bear this legend.
 18  **
 19  **
 20  ** map64.c
 21  **
 22  ** mapper 64 interface
 23  ** $Id: map064.c,v 1.2 2001/04/27 14:37:11 neil Exp $
 24  */
 25  
 26  #include "noftypes.h"
 27  #include "nes_mmc.h"
 28  #include "nes.h"
 29  #include "log.h"
 30  
 31  static struct
 32  {
 33     int counter, latch;
 34     bool enabled, reset;
 35  } irq;
 36  
 37  static uint8 command = 0;
 38  static uint16 vrombase = 0x0000;
 39  
 40  static void map64_hblank(int vblank)
 41  {
 42     if (vblank)
 43        return;
 44  
 45     irq.reset = false;
 46  
 47     if (ppu_enabled())
 48     {
 49        if (0 == irq.counter--)
 50        {
 51           irq.counter = irq.latch;
 52         
 53           if (true == irq.enabled)
 54              nes_irq();
 55  
 56           irq.reset = true;
 57        }
 58     }
 59  }
 60  
 61  /* mapper 64: Tengen RAMBO-1 */
 62  static void map64_write(uint32 address, uint8 value)
 63  {
 64     switch (address & 0xE001)
 65     {
 66     case 0x8000:
 67        command = value;
 68        vrombase = (value & 0x80) ? 0x1000 : 0x0000;
 69        break;
 70  
 71     case 0x8001:
 72        switch (command & 0xF)
 73        {
 74        case 0:
 75           mmc_bankvrom(1, 0x0000 ^ vrombase, value);
 76           mmc_bankvrom(1, 0x0400 ^ vrombase, value);
 77           break;
 78  
 79        case 1:
 80           mmc_bankvrom(1, 0x0800 ^ vrombase, value);
 81           mmc_bankvrom(1, 0x0C00 ^ vrombase, value);
 82           break;
 83  
 84        case 2:
 85           mmc_bankvrom(1, 0x1000 ^ vrombase, value);
 86           break;
 87  
 88        case 3:
 89           mmc_bankvrom(1, 0x1400 ^ vrombase, value);
 90           break;
 91  
 92        case 4:
 93           mmc_bankvrom(1, 0x1800 ^ vrombase, value);
 94           break;
 95  
 96        case 5:
 97           mmc_bankvrom(1, 0x1C00 ^ vrombase, value);
 98           break;
 99  
100        case 6:
101           mmc_bankrom(8, (command & 0x40) ? 0xA000 : 0x8000, value);
102           break;
103  
104        case 7:
105           mmc_bankrom(8, (command & 0x40) ? 0xC000 : 0xA000, value);
106           break;
107  
108        case 8:
109           mmc_bankvrom(1, 0x0400, value);
110           break;
111  
112        case 9:
113           mmc_bankvrom(1, 0x0C00, value);
114           break;
115  
116        case 15:
117           mmc_bankrom(8, (command & 0x40) ? 0x8000 : 0xC000, value);
118           break;
119  
120        default:
121  #ifdef NOFRENDO_DEBUG
122           log_printf("mapper 64: unknown command #%d", command & 0xF);
123  #endif
124           break;
125        }
126        break;
127     
128     case 0xA000:
129        if (value & 1)
130           ppu_mirror(0, 0, 1, 1);
131        else
132           ppu_mirror(0, 1, 0, 1);
133        break;
134     
135     case 0xC000:
136        //irq.counter = value;
137        irq.latch = value;
138        break;
139     
140     case 0xC001:
141        //irq.latch = value;
142        irq.reset = true;
143        break;
144     
145     case 0xE000:
146        //irq.counter = irq.latch;
147        irq.enabled = false;
148        break;
149     
150     case 0xE001:
151        irq.enabled = true;
152        break;
153     
154     default:
155  #ifdef NOFRENDO_DEBUG
156        log_printf("mapper 64: Wrote $%02X to $%04X", value, address);
157  #endif
158        break;
159     }
160  
161     if (true == irq.reset)
162        irq.counter = irq.latch;
163  }
164  
165  static void map64_init(void)
166  {
167     mmc_bankrom(8, 0x8000, MMC_LASTBANK);
168     mmc_bankrom(8, 0xA000, MMC_LASTBANK);
169     mmc_bankrom(8, 0xC000, MMC_LASTBANK);
170     mmc_bankrom(8, 0xE000, MMC_LASTBANK);
171  
172     irq.counter = irq.latch = 0;
173     irq.reset = irq.enabled = false;
174  }
175  
176  static const map_memwrite map64_memwrite[] =
177  {
178     { 0x8000, 0xFFFF, map64_write },
179     {     -1,     -1, NULL }
180  };
181  
182  const mapintf_t map64_intf =
183  {
184     64, /* mapper number */
185     "Tengen RAMBO-1", /* mapper name */
186     map64_init, /* init routine */
187     NULL, /* vblank callback */
188     map64_hblank, /* hblank callback */
189     NULL, /* get state (snss) */
190     NULL, /* set state (snss) */
191     NULL, /* memory read structure */
192     map64_memwrite, /* memory write structure */
193     NULL /* external sound device */
194  };
195  
196  /*
197  ** $Log: map064.c,v $
198  ** Revision 1.2  2001/04/27 14:37:11  neil
199  ** wheeee
200  **
201  ** Revision 1.1  2001/04/27 12:54:40  neil
202  ** blah
203  **
204  ** Revision 1.1.1.1  2001/04/27 07:03:54  neil
205  ** initial
206  **
207  ** Revision 1.1  2000/10/24 12:19:33  matt
208  ** changed directory structure
209  **
210  ** Revision 1.8  2000/10/22 19:17:46  matt
211  ** mapper cleanups galore
212  **
213  ** Revision 1.7  2000/10/22 15:03:13  matt
214  ** simplified mirroring
215  **
216  ** Revision 1.6  2000/10/21 19:33:38  matt
217  ** many more cleanups
218  **
219  ** Revision 1.5  2000/10/10 13:58:17  matt
220  ** stroustrup squeezing his way in the door
221  **
222  ** Revision 1.4  2000/07/10 13:51:25  matt
223  ** using generic nes_irq() routine now
224  **
225  ** Revision 1.3  2000/07/10 05:29:03  matt
226  ** cleaned up some mirroring issues
227  **
228  ** Revision 1.2  2000/07/06 02:48:43  matt
229  ** clearly labelled structure members
230  **
231  ** Revision 1.1  2000/07/05 05:05:18  matt
232  ** initial revision
233  **
234  */