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executable file 389 lines (320 sloc) 8.81 KB
/* gameplaySP
*
* Copyright (C) 2006 Exophase <exophase@gmail.com>
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
cheat_type cheats[MAX_CHEATS];
u32 num_cheats;
void decrypt_gsa_code(u32 *address_ptr, u32 *value_ptr, cheat_variant_enum
cheat_variant)
{
u32 i, i2, code_position;
u32 address = *address_ptr;
u32 value = *value_ptr;
u32 r = 0xc6ef3720;
u32 seeds_v1[4] =
{
0x09f4fbbd, 0x9681884a, 0x352027e9, 0xf3dee5a7
};
u32 seeds_v3[4] =
{
0x7aa9648f, 0x7fae6994, 0xc0efaad5, 0x42712c57
};
u32 *seeds;
if(cheat_variant == CHEAT_TYPE_GAMESHARK_V1)
seeds = seeds_v1;
else
seeds = seeds_v3;
for(i = 0; i < 32; i++)
{
value -= ((address << 4) + seeds[2]) ^ (address + r) ^
((address >> 5) + seeds[3]);
address -= ((value << 4) + seeds[0]) ^ (value + r) ^
((value >> 5) + seeds[1]);
r -= 0x9e3779b9;
}
*address_ptr = address;
*value_ptr = value;
}
void add_cheats(u8 *cheats_filename)
{
FILE *cheats_file;
u8 current_line[256];
u8 *name_ptr;
u32 *cheat_code_ptr;
u32 address, value;
u32 num_cheat_lines;
u32 cheat_name_length;
cheat_variant_enum current_cheat_variant;
num_cheats = 0;
cheats_file = fopen(cheats_filename, "rb");
if(cheats_file)
{
while(fgets(current_line, 256, cheats_file))
{
// Get the header line first
name_ptr = strchr(current_line, ' ');
if(name_ptr)
{
*name_ptr = 0;
name_ptr++;
}
if(!strcasecmp(current_line, "gameshark_v1") ||
!strcasecmp(current_line, "gameshark_v2") ||
!strcasecmp(current_line, "PAR_v1") ||
!strcasecmp(current_line, "PAR_v2"))
{
current_cheat_variant = CHEAT_TYPE_GAMESHARK_V1;
}
else
if(!strcasecmp(current_line, "gameshark_v3") ||
!strcasecmp(current_line, "PAR_v3"))
{
current_cheat_variant = CHEAT_TYPE_GAMESHARK_V3;
}
else
{
current_cheat_variant = CHEAT_TYPE_INVALID;
}
if(current_cheat_variant != CHEAT_TYPE_INVALID)
{
strncpy(cheats[num_cheats].cheat_name, name_ptr, CHEAT_NAME_LENGTH - 1);
cheats[num_cheats].cheat_name[CHEAT_NAME_LENGTH - 1] = 0;
cheat_name_length = strlen(cheats[num_cheats].cheat_name);
if(cheat_name_length &&
(cheats[num_cheats].cheat_name[cheat_name_length - 1] == '\n') ||
(cheats[num_cheats].cheat_name[cheat_name_length - 1] == '\r'))
{
cheats[num_cheats].cheat_name[cheat_name_length - 1] = 0;
cheat_name_length--;
}
if(cheat_name_length &&
cheats[num_cheats].cheat_name[cheat_name_length - 1] == '\r')
{
cheats[num_cheats].cheat_name[cheat_name_length - 1] = 0;
}
cheats[num_cheats].cheat_variant = current_cheat_variant;
cheat_code_ptr = cheats[num_cheats].cheat_codes;
num_cheat_lines = 0;
while(fgets(current_line, 256, cheats_file))
{
if(strlen(current_line) < 3)
break;
sscanf(current_line, "%08x %08x", &address, &value);
decrypt_gsa_code(&address, &value, current_cheat_variant);
cheat_code_ptr[0] = address;
cheat_code_ptr[1] = value;
cheat_code_ptr += 2;
num_cheat_lines++;
}
cheats[num_cheats].num_cheat_lines = num_cheat_lines;
num_cheats++;
}
}
fclose(cheats_file);
}
}
void process_cheat_gs1(cheat_type *cheat)
{
u32 cheat_opcode;
u32 *code_ptr = cheat->cheat_codes;
u32 address, value;
u32 i;
for(i = 0; i < cheat->num_cheat_lines; i++)
{
address = code_ptr[0];
value = code_ptr[1];
code_ptr += 2;
cheat_opcode = address >> 28;
address &= 0xFFFFFFF;
switch(cheat_opcode)
{
case 0x0:
write_memory8(address, value);
break;
case 0x1:
write_memory16(address, value);
break;
case 0x2:
write_memory32(address, value);
break;
case 0x3:
{
u32 num_addresses = address & 0xFFFF;
u32 address1, address2;
u32 i2;
for(i2 = 0; i2 < num_addresses; i2++)
{
address1 = code_ptr[0];
address2 = code_ptr[1];
code_ptr += 2;
i++;
write_memory32(address1, value);
if(address2 != 0)
write_memory32(address2, value);
}
break;
}
// ROM patch not supported yet
case 0x6:
break;
// GS button down not supported yet
case 0x8:
break;
// Reencryption (DEADFACE) not supported yet
case 0xD:
if(read_memory16(address) != (value & 0xFFFF))
{
code_ptr += 2;
i++;
}
break;
case 0xE:
if(read_memory16(value & 0xFFFFFFF) != (address & 0xFFFF))
{
u32 skip = ((address >> 16) & 0x03);
code_ptr += skip * 2;
i += skip;
}
break;
// Hook routine not supported yet (not important??)
case 0x0F:
break;
}
}
}
// These are especially incomplete.
void process_cheat_gs3(cheat_type *cheat)
{
u32 cheat_opcode;
u32 *code_ptr = cheat->cheat_codes;
u32 address, value;
u32 i;
for(i = 0; i < cheat->num_cheat_lines; i++)
{
address = code_ptr[0];
value = code_ptr[1];
code_ptr += 2;
cheat_opcode = address >> 28;
address &= 0xFFFFFFF;
switch(cheat_opcode)
{
case 0x0:
cheat_opcode = address >> 24;
address = (address & 0xFFFFF) + ((address << 4) & 0xF000000);
switch(cheat_opcode)
{
case 0x0:
{
u32 iterations = value >> 24;
u32 i2;
value &= 0xFF;
for(i2 = 0; i2 <= iterations; i2++, address++)
{
write_memory8(address, value);
}
break;
}
case 0x2:
{
u32 iterations = value >> 16;
u32 i2;
value &= 0xFFFF;
for(i2 = 0; i2 <= iterations; i2++, address += 2)
{
write_memory16(address, value);
}
break;
}
case 0x4:
write_memory32(address, value);
break;
}
break;
case 0x4:
cheat_opcode = address >> 24;
address = (address & 0xFFFFF) + ((address << 4) & 0xF000000);
switch(cheat_opcode)
{
case 0x0:
address = read_memory32(address) + (value >> 24);
write_memory8(address, value & 0xFF);
break;
case 0x2:
address = read_memory32(address) + ((value >> 16) * 2);
write_memory16(address, value & 0xFFFF);
break;
case 0x4:
address = read_memory32(address);
write_memory32(address, value);
break;
}
break;
case 0x8:
cheat_opcode = address >> 24;
address = (address & 0xFFFFF) + ((address << 4) & 0xF000000);
switch(cheat_opcode)
{
case 0x0:
value = (value & 0xFF) + read_memory8(address);
write_memory8(address, value);
break;
case 0x2:
value = (value & 0xFFFF) + read_memory16(address);
write_memory16(address, value);
break;
case 0x4:
value = value + read_memory32(address);
write_memory32(address, value);
break;
}
break;
case 0xC:
cheat_opcode = address >> 24;
address = (address & 0xFFFFFF) + 0x4000000;
switch(cheat_opcode)
{
case 0x6:
write_memory16(address, value);
break;
case 0x7:
write_memory32(address, value);
break;
}
break;
}
}
}
void process_cheats()
{
u32 i;
for(i = 0; i < num_cheats; i++)
{
if(cheats[i].cheat_active)
{
switch(cheats[i].cheat_variant)
{
case CHEAT_TYPE_GAMESHARK_V1:
process_cheat_gs1(cheats + i);
break;
case CHEAT_TYPE_GAMESHARK_V3:
process_cheat_gs3(cheats + i);
break;
}
}
}
}