apps/plugins/pacbox/hardware.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Pacbox - a Pacman Emulator for Rockbox
  11  *
  12  * Based on PIE - Pacman Instructional Emulator
  13  *
  14  * Copyright (c) 1997-2003,2004 Alessandro Scotti
  15  * http://www.ascotti.org/
  16  *
  17  * This program is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU General Public License
  19  * as published by the Free Software Foundation; either version 2
  20  * of the License, or (at your option) any later version.
  21  *
  22  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  23  * KIND, either express or implied.
  24  *
  25  ****************************************************************************/
  26
  27 #include "plugin.h"
  28 #include "hardware.h"
  29
  30 /* The main data for Pacman  */
  31
  32 unsigned char ram_[20*1024] IBSS_ATTR;          // ROM (16K) and RAM (4K)
  33 unsigned char charset_rom_[4*1024] IBSS_ATTR;   // Character set ROM (4K)
  34 unsigned char spriteset_rom_[4*1024] IBSS_ATTR; // Sprite set ROM (4K)
  35 unsigned char dirty_[1024] IBSS_ATTR;
  36 unsigned char video_mem_[1024] IBSS_ATTR;       // Video memory (1K)
  37 unsigned char color_mem_[1024] IBSS_ATTR;       // Color memory (1K)
  38 unsigned char charmap_[256*8*8] IBSS_ATTR;    /* Character data for 256 8x8 characters */
  39 unsigned char spritemap_[64*16*16]; /* Sprite data for 64 16x16 sprites */
  40 unsigned char output_devices_ IBSS_ATTR;  /* Output flip-flops set by the game program */
  41 unsigned char interrupt_vector_ IBSS_ATTR;
  42 unsigned      coin_counter_ IBSS_ATTR;
  43 unsigned char port1_ IBSS_ATTR;
  44 unsigned char port2_ IBSS_ATTR;
  45 unsigned char dip_switches_ IBSS_ATTR;
  46
  47 /* Internal tables and structures for faster access to data */
  48 struct PacmanSprite sprites_[8];    /* Sprites */
  49 short vchar_to_i_[1024];
  50
  51
  52 /*
  53     For Z80 Environment: write a byte to memory.
  54 */
  55 void writeByte( unsigned addr, unsigned char b )
  56 {
  57     addr &= 0x7FFF;
  58
  59     if( addr < 0x4000 ) {
  60         // This is a ROM address, do not write into it!
  61     }
  62     else if( addr < 0x4400 ) {
  63         // Video memory
  64         if (ram_[addr] != b) {
  65             int x = vchar_to_i_[addr-0x4000];
  66             ram_[addr] = b;
  67             dirty_[x] = 1;
  68             video_mem_[x] = b;
  69         }
  70     }
  71     else if( addr < 0x4800 ) {
  72         // Color memory
  73         if (ram_[addr] != b) {
  74             int x = vchar_to_i_[addr-0x4400];
  75             ram_[addr] = b;
  76             dirty_[x] = 1;
  77             color_mem_[x] = b;
  78         }
  79     }
  80     else if( addr < 0x4FF0 ) {
  81         // Standard memory
  82         ram_[addr] = b;
  83     }
  84     else if( addr < 0x5000 ) {
  85         // Sprites
  86         ram_[addr] = b;
  87
  88         unsigned idx = (addr - 0x4FF0) / 2;
  89
  90         if( addr & 1 ) {
  91             sprites_[ idx ].color = b;
  92         }
  93         else {
  94             sprites_[ idx ].n = b >> 2;
  95             sprites_[ idx ].mode = b & 0x03;
  96         }
  97     }
  98     else {
  99     // Memory mapped ports
 100     switch( addr ) {
 101         case 0x5000:
 102             // Interrupt enable
 103             setOutputFlipFlop( InterruptEnabled, b & 0x01 );
 104             break;
 105         case 0x5001:
 106             // Sound enable
 107             setOutputFlipFlop( SoundEnabled, b & 0x01 );
 108             break;
 109         case 0x5002:
 110             // Aux board enable?
 111             break;
 112         case 0x5003:
 113             // Flip screen
 114             setOutputFlipFlop( FlipScreen, b & 0x01 );
 115             break;
 116         case 0x5004:
 117             // Player 1 start light
 118             setOutputFlipFlop( PlayerOneLight, b & 0x01 );
 119             break;
 120         case 0x5005:
 121             // Player 2 start light
 122             setOutputFlipFlop( PlayerTwoLight, b & 0x01 );
 123             break;
 124         case 0x5006:
 125             // Coin lockout: bit 0 is used to enable/disable the coin insert slots
 126             // (0=disable).
 127             // The coin slot is enabled at startup and (temporarily) disabled when
 128             // the maximum number of credits (99) is inserted.
 129             setOutputFlipFlop( CoinLockout, b & 0x01 );
 130             break;
 131         case 0x5007:
 132             // Coin meter (coin counter incremented on 0/1 edge)
 133             if( (output_devices_ & CoinMeter) == 0 && (b & 0x01) != 0 )
 134                 coin_counter_++;
 135             setOutputFlipFlop( CoinMeter, b & 0x01 );
 136             break;
 137         case 0x50c0:
 138             // Watchdog reset
 139             break;
 140         default:
 141             if( addr >= 0x5040 && addr < 0x5060 ) {
 142                 // Sound registers
 143                 //SOUND sound_chip_.setRegister( addr-0x5040, b );
 144             }
 145             else if( addr >= 0x5060 && addr < 0x5070 ) {
 146                 // Sprite coordinates, x/y pairs for 8 sprites
 147                 unsigned idx = (addr-0x5060) / 2;
 148
 149                 if( addr & 1 ) {
 150                     sprites_[ idx ].y = 272 - b + 1;
 151                 }
 152                 else {
 153                     sprites_[ idx ].x = 240 - b - 1;
 154
 155                     if( idx <= 2 ) {
 156                         // In Pacman the first few sprites must be further offset
 157                         // to the left to get a correct display (is this a hack?)
 158                         sprites_[ idx ].x -= 1;
 159                     }
 160                 }
 161             }
 162             break;
 163         }
 164     }
 165 }
 166
 167 /*
 168     For Z80 Environment: read from a port.
 169
 170     Note: all ports in Pacman are memory mapped so they are read with readByte().
 171 */
 172 unsigned char readPort( unsigned port )
 173 {
 174     (void)port;
 175     return 0;
 176 }
 177
 178 /*
 179     For Z80 Environment: write to a port.
 180 */
 181 void writePort( unsigned addr, unsigned char b )
 182 {
 183     if( addr == 0 ) {
 184         // Sets the interrupt vector for the next CPU interrupt
 185         interrupt_vector_ = b;
 186     }
 187 }
 188
 189 void setOutputFlipFlop( unsigned char bit, unsigned char value )
 190 {
 191     if( value ) {
 192         output_devices_ |= bit;
 193     }
 194     else {
 195         output_devices_ &= ~bit;
 196     }
 197 }