map085.c
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 ** map85.c 21 ** 22 ** mapper 85 interface 23 ** $Id: map085.c,v 1.3 2001/05/06 01:42:03 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 int wait_state; 35 bool enabled; 36 } irq; 37 38 /* mapper 85: Konami VRC7 */ 39 static void map85_write(uint32 address, uint8 value) 40 { 41 uint8 bank = address >> 12; 42 uint8 reg = (address & 0x10) | ((address & 0x08) << 1); 43 44 switch (bank) 45 { 46 case 0x08: 47 if (0x10 == reg) 48 mmc_bankrom(8, 0xA000, value); 49 else 50 mmc_bankrom(8, 0x8000, value); 51 break; 52 53 case 0x09: 54 /* 0x10 & 0x30 should be trapped by sound emulation */ 55 mmc_bankrom(8, 0xC000, value); 56 break; 57 58 case 0x0A: 59 if (0x10 == reg) 60 mmc_bankvrom(1, 0x0400, value); 61 else 62 mmc_bankvrom(1, 0x0000, value); 63 break; 64 65 case 0x0B: 66 if (0x10 == reg) 67 mmc_bankvrom(1, 0x0C00, value); 68 else 69 mmc_bankvrom(1, 0x0800, value); 70 break; 71 72 case 0x0C: 73 if (0x10 == reg) 74 mmc_bankvrom(1, 0x1400, value); 75 else 76 mmc_bankvrom(1, 0x1000, value); 77 break; 78 79 case 0x0D: 80 if (0x10 == reg) 81 mmc_bankvrom(1, 0x1C00, value); 82 else 83 mmc_bankvrom(1, 0x1800, value); 84 break; 85 86 case 0x0E: 87 if (0x10 == reg) 88 { 89 irq.latch = value; 90 } 91 else 92 { 93 switch (value & 3) 94 { 95 case 0: 96 ppu_mirror(0, 1, 0, 1); /* vertical */ 97 break; 98 99 case 1: 100 ppu_mirror(0, 0, 1, 1); /* horizontal */ 101 break; 102 103 case 2: 104 ppu_mirror(0, 0, 0, 0); 105 break; 106 107 case 3: 108 ppu_mirror(1, 1, 1, 1); 109 break; 110 } 111 } 112 break; 113 114 case 0x0F: 115 if (0x10 == reg) 116 { 117 irq.enabled = irq.wait_state; 118 } 119 else 120 { 121 irq.wait_state = value & 0x01; 122 irq.enabled = (value & 0x02) ? true : false; 123 if (true == irq.enabled) 124 irq.counter = irq.latch; 125 } 126 break; 127 128 default: 129 #ifdef NOFRENDO_DEBUG 130 log_printf("unhandled vrc7 write: $%02X to $%04X\n", value, address); 131 #endif /* NOFRENDO_DEBUG */ 132 break; 133 } 134 } 135 136 static void map85_hblank(int vblank) 137 { 138 UNUSED(vblank); 139 140 if (irq.enabled) 141 { 142 if (++irq.counter > 0xFF) 143 { 144 irq.counter = irq.latch; 145 nes_irq(); 146 147 //return; 148 } 149 //irq.counter++; 150 } 151 } 152 153 static const map_memwrite map85_memwrite[] = 154 { 155 { 0x8000, 0xFFFF, map85_write }, 156 { -1, -1, NULL } 157 }; 158 159 static void map85_init(void) 160 { 161 mmc_bankrom(16, 0x8000, 0); 162 mmc_bankrom(16, 0xC000, MMC_LASTBANK); 163 164 mmc_bankvrom(8, 0x0000, 0); 165 166 irq.counter = irq.latch = 0; 167 irq.wait_state = 0; 168 irq.enabled = false; 169 } 170 171 const mapintf_t map85_intf = 172 { 173 85, /* mapper number */ 174 "Konami VRC7", /* mapper name */ 175 map85_init, /* init routine */ 176 NULL, /* vblank callback */ 177 map85_hblank, /* hblank callback */ 178 NULL, /* get state (snss) */ 179 NULL, /* set state (snss) */ 180 NULL, /* memory read structure */ 181 map85_memwrite, /* memory write structure */ 182 NULL 183 }; 184 185 /* 186 ** $Log: map085.c,v $ 187 ** Revision 1.3 2001/05/06 01:42:03 neil 188 ** boooo 189 ** 190 ** Revision 1.2 2001/04/27 14:37:11 neil 191 ** wheeee 192 ** 193 ** Revision 1.1 2001/04/27 12:54:40 neil 194 ** blah 195 ** 196 ** Revision 1.1.1.1 2001/04/27 07:03:54 neil 197 ** initial 198 ** 199 ** Revision 1.1 2000/10/24 12:19:33 matt 200 ** changed directory structure 201 ** 202 ** Revision 1.10 2000/10/22 19:17:46 matt 203 ** mapper cleanups galore 204 ** 205 ** Revision 1.9 2000/10/22 15:03:14 matt 206 ** simplified mirroring 207 ** 208 ** Revision 1.8 2000/10/21 19:33:38 matt 209 ** many more cleanups 210 ** 211 ** Revision 1.7 2000/10/10 13:58:17 matt 212 ** stroustrup squeezing his way in the door 213 ** 214 ** Revision 1.6 2000/08/16 02:50:11 matt 215 ** random mapper cleanups 216 ** 217 ** Revision 1.5 2000/07/23 14:37:21 matt 218 ** added a break statement 219 ** 220 ** Revision 1.4 2000/07/15 23:52:19 matt 221 ** rounded out a bunch more mapper interfaces 222 ** 223 ** Revision 1.3 2000/07/10 13:51:25 matt 224 ** using generic nes_irq() routine now 225 ** 226 ** Revision 1.2 2000/07/10 05:29:03 matt 227 ** cleaned up some mirroring issues 228 ** 229 ** Revision 1.1 2000/07/06 02:47:47 matt 230 ** initial revision 231 ** 232 */