Genesis-Plus-GX/source/cart_hw/datel.c

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/****************************************************************************
* Genesis Plus
* Action Replay / Pro Action Replay emulation
*
* Copyright (C) 2009 Eke-Eke (GCN/Wii port)
*
* Based on reverse-engineering done on DATEL softwares
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
***************************************************************************/
#include "shared.h"
#ifdef TEST_AR
static struct
{
uint8 enabled;
uint8 rom[0x10000];
uint16 regs[13];
uint16 old[4];
uint16 data[4];
uint32 addr[4];
} action_replay;
static void ar_write_byte(uint32 address, uint32 data);
static void ar_write_regs(uint32 address, uint32 data);
static void ar_write_word(uint32 address, uint32 data);
void ar_init(void)
{
memset(&action_replay,0,sizeof(action_replay));
/* load Game Genie ROM program */
FILE *f = fopen("./areplay.bin","rb");
if (!f) return;
fread(action_replay.rom,1,0x8000,f);
fclose(f);
/* $0000-$7fff mirrored into $8000-$ffff */
memcpy(action_replay.rom+0x8000,action_replay.rom,0x8000);
#ifdef LSB_FIRST
/* Byteswap ROM */
int i;
uint8 temp;
for(i = 0; i < 0x10000; i += 2)
{
temp = action_replay.rom[i];
action_replay.rom[i] = action_replay.rom[i+1];
action_replay.rom[i+1] = temp;
}
#endif
/* enable registers write */
m68k_memory_map[1].write16 = ar_write_regs;
/* set flag */
action_replay.enabled = 1;
}
void ar_reset(void)
{
if (!action_replay.enabled) return;
/* restore patched ROM */
int i;
for (i=0; i<4; i++)
{
if (action_replay.addr[i] < 0x400000)
*(uint16 *)(cart_rom + action_replay.addr[i]) = action_replay.old[i];
}
/* reset internal state */
memset(action_replay.regs,0,sizeof(action_replay.regs));
memset(action_replay.old,0,sizeof(action_replay.old));
memset(action_replay.data,0,sizeof(action_replay.data));
memset(action_replay.addr,0,sizeof(action_replay.addr));
/* slot 0 is mapped to Action replay ROM */
m68k_memory_map[0].base = action_replay.rom;
/* reset RAM handlers */
for (i=0xe0; i<0x100; i++)
{
m68k_memory_map[i].write8 = NULL;
m68k_memory_map[i].write16 = NULL;
}
}
static void ar_write_byte(uint32 address, uint32 data)
{
}
static void ar_write_word(uint32 address, uint32 data)
{
}
static void ar_write_regs(uint32 address, uint32 data)
{
if ((address > 0x10018) || (action_replay.regs[3] == 0xffff))
{
m68k_unused_16_w(address,data);
return;
}
/* register offset */
int offset = (address >> 1) & 0x0F;
/* update internal register */
action_replay.regs[offset] = data;
/* decode patch value & address on exit */
if ((offset == 3) && (data == 0xffff))
{
/* patch data */
action_replay.data[0] = action_replay.regs[0];
action_replay.data[1] = action_replay.regs[4];
action_replay.data[2] = action_replay.regs[7];
action_replay.data[3] = action_replay.regs[10];
/* patch address */
action_replay.addr[0] = (action_replay.regs[1] | ((action_replay.regs[2] & 0x7f00) << 8)) << 1;
action_replay.addr[1] = (action_replay.regs[5] | ((action_replay.regs[6] & 0x7f00) << 8)) << 1;
action_replay.addr[2] = (action_replay.regs[8] | ((action_replay.regs[9] & 0x7f00) << 8)) << 1;
action_replay.addr[3] = (action_replay.regs[11] | ((action_replay.regs[12] & 0x7f00) << 8)) << 1;
int i;
for (i=0; i<4; i++)
{
offset = action_replay.addr[i] >> 16;
/* ROM area */
if (offset < 0x40)
{
/* store old ROM value */
action_replay.old[i] = *(uint16 *)(cart_rom + action_replay.addr[i]);
}
/* Work RAM area */
else if (offset >= 0xe0)
{
/* patch RAM */
*(uint16 *)(work_ram + (action_replay.addr[i] & 0xffff)) = action_replay.data[i];
/* setup handlers */
m68k_memory_map[offset].write8 = ar_write_byte;
m68k_memory_map[offset].write16 = ar_write_word;
}
}
for (i=0; i<4; i++)
{
offset = action_replay.addr[i] >> 16;
/* ROM area */
if (offset < 0x40)
{
/* patch ROM */
*(uint16 *)(cart_rom + action_replay.addr[i]) = action_replay.data[i];;
}
}
/* reads are mapped to Cartridge ROM */
m68k_memory_map[0].base = cart_rom;
}
}
#endif