cen64/si/cic.c
2018-04-28 01:36:31 +01:00

112 lines
2.6 KiB
C

//
// si/cic.c: PIF CIC security/lock out algorithms.
//
// CEN64: Cycle-Accurate Nintendo 64 Emulator.
// Copyright (C) 2015, Tyler J. Stachecki.
//
// This file is subject to the terms and conditions defined in
// 'LICENSE', which is part of this source code package.
//
#include "common.h"
#include "si/cic.h"
// CIC seeds and status bits passed from PIF to IPL through PIF RAM
// Bits | Description
// 00080000 | ROM type (0 = Game Pack, 1 = DD)
// 00040000 | Version
// 00020000 | Reset Type (0 = cold reset, 1 = NMI)
// 0000FF00 | CIC IPL3 seed value
// 000000FF | CIC IPL2 seed value
#define CIC_SEED_NUS_5101 0x0000AC00U
#define CIC_SEED_NUS_6101 0x00043F3FU
#define CIC_SEED_NUS_6102 0x00003F3FU
#define CIC_SEED_NUS_6103 0x0000783FU
#define CIC_SEED_NUS_6105 0x0000913FU
#define CIC_SEED_NUS_6106 0x0000853FU
#define CIC_SEED_NUS_8303 0x0000DD00U
#define CRC_NUS_5101 0x587BD543U
#define CRC_NUS_6101 0x6170A4A1U
#define CRC_NUS_7102 0x009E9EA3U
#define CRC_NUS_6102 0x90BB6CB5U
#define CRC_NUS_6103 0x0B050EE0U
#define CRC_NUS_6105 0x98BC2C86U
#define CRC_NUS_6106 0xACC8580AU
#define CRC_NUS_8303 0x0E018159U
#define CRC_iQue_1 0xCD19FEF1U
#define CRC_iQue_2 0xB98CED9AU
#define CRC_iQue_3 0xE71C2766U
cen64_cold static uint32_t si_crc32(const uint8_t *data, size_t size);
// Determines the CIC seed for a cart, given the ROM data.
int get_cic_seed(const uint8_t *rom_data, uint32_t *cic_seed) {
uint32_t crc = si_crc32(rom_data + 0x40, 0x1000 - 0x40);
uint32_t aleck64crc = si_crc32(rom_data + 0x40, 0xC00 - 0x40);
if (aleck64crc == CRC_NUS_5101) *cic_seed = CIC_SEED_NUS_5101;
else switch (crc) {
case CRC_NUS_6101:
case CRC_NUS_7102:
case CRC_iQue_1:
case CRC_iQue_2:
case CRC_iQue_3:
*cic_seed = CIC_SEED_NUS_6101;
break;
case CRC_NUS_6102:
*cic_seed = CIC_SEED_NUS_6102;
break;
case CRC_NUS_6103:
*cic_seed = CIC_SEED_NUS_6103;
break;
case CRC_NUS_6105:
*cic_seed = CIC_SEED_NUS_6105;
break;
case CRC_NUS_6106:
*cic_seed = CIC_SEED_NUS_6106;
break;
case CRC_NUS_8303:
*cic_seed = CIC_SEED_NUS_8303;
break;
default:
*cic_seed = 0;
return 1;
}
return 0;
}
uint32_t si_crc32(const uint8_t *data, size_t size) {
uint32_t table[256];
unsigned n, k;
uint32_t c;
for (n = 0; n < 256; n++) {
c = (uint32_t) n;
for (k = 0; k < 8; k++) {
if (c & 1)
c = 0xEDB88320L ^ (c >> 1);
else
c = c >> 1;
}
table[n] = c;
}
c = 0L ^ 0xFFFFFFFF;
for (n = 0; n < size; n++)
c = table[(c ^ data[n]) & 0xFF] ^ (c >> 8);
return c ^ 0xFFFFFFFF;
}