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snesb.cpp: simplified decryption for wldgunsb [iq_132]

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Ivan Vangelista 2020-08-28 22:48:03 +02:00
parent 4fb8527926
commit e46f2d614b
1 changed files with 10 additions and 24 deletions
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34
src/mame/drivers/snesb.cpp
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@ -33,7 +33,7 @@ TODO:
- legendsb : unknown dipswitches
- rushbets : dipswitches (stored at memory locations $785006 and $785008)
- venom : gfx glitches on second level
- wldgunsb : check if it doesn't work because of protection or some bug in the decryption
- wldgunsb : protection simulation
***************************************************************************
@ -1363,44 +1363,30 @@ void snesb_state::init_wldgunsb()
uint8_t *dst = memregion("user3")->base();
static uint8_t address_tab_high[0x20] = {
// 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
0x0b, 0x1d, 0x05, 0x15, 0x09, 0x19, 0x04, 0x13, 0x02, 0x1f, 0x07, 0x17, 0x0d, 0x11, 0x0a, 0x1a, // unkn
0x14, 0x0e, 0x18, 0x06, 0x1e, 0x01, 0x10, 0x0c, 0x1b, 0x0f, 0x16, 0x00, 0x12, 0x08, 0x1c, 0x03 // 0x10
0x0b, 0x1d, 0x05, 0x15, 0x09, 0x19, 0x04, 0x13, 0x02, 0x1f, 0x07, 0x17, 0x0d, 0x11, 0x0a, 0x1a,
0x14, 0x0e, 0x18, 0x06, 0x1e, 0x01, 0x10, 0x0c, 0x1b, 0x0f, 0x16, 0x00, 0x12, 0x08, 0x1c, 0x03
};
static uint8_t address_tab_low[0x40] = {
// 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
0x14, 0x1d, 0x11, 0x3c, 0x0a, 0x29, 0x2d, 0x2e, 0x30, 0x32, 0x16, 0x36, 0x05, 0x25, 0x26, 0x37,
0x20, 0x21, 0x27, 0x28, 0x33, 0x34, 0x23, 0x12, 0x1e, 0x1f, 0x3b, 0x24, 0x2c, 0x35, 0x38, 0x39,
0x3d, 0x0c, 0x2a, 0x0d, 0x22, 0x18, 0x19, 0x1a, 0x03, 0x08, 0x04, 0x3a, 0x0b, 0x0f, 0x15, 0x17,
0x1b, 0x13, 0x00, 0x1c, 0x2b, 0x01, 0x06, 0x2f, 0x07, 0x09, 0x02, 0x31, 0x10, 0x0e, 0x3f, 0x3e
};
static uint8_t data_table[0x100] = {
// 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
0x35, 0xad, 0x85, 0xb5, 0x95, 0x05, 0x25, 0xa5, 0x0d, 0xbd, 0x3d, 0x1d, 0x8d, 0x15, 0x2d, 0x9d, // 0x00
0x73, 0xeb, 0xc3, 0xf3, 0xd3, 0x43, 0x63, 0xe3, 0x4b, 0xfb, 0x7b, 0x5b, 0xcb, 0x53, 0x6b, 0xdb, // 0x10
0x70, 0xe8, 0xc0, 0xf0, 0xd0, 0x40, 0x60, 0xe0, 0x48, 0xf8, 0x78, 0x58, 0xc8, 0x50, 0x68, 0xd8, // 0x20
0x75, 0xed, 0xc5, 0xf5, 0xd5, 0x45, 0x65, 0xe5, 0x4d, 0xfd, 0x7d, 0x5d, 0xcd, 0x55, 0x6d, 0xdd, // 0x30
0x74, 0xec, 0xc4, 0xf4, 0xd4, 0x44, 0x64, 0xe4, 0x4c, 0xfc, 0x7c, 0x5c, 0xcc, 0x54, 0x6c, 0xdc, // 0x40
0x30, 0xa8, 0x80, 0xb0, 0x90, 0x00, 0x20, 0xa0, 0x08, 0xb8, 0x38, 0x18, 0x88, 0x10, 0x28, 0x98, // 0x50
0x31, 0xa9, 0x81, 0xb1, 0x91, 0x01, 0x21, 0xa1, 0x09, 0xb9, 0x39, 0x19, 0x89, 0x11, 0x29, 0x99, // 0x60
0x71, 0xe9, 0xc1, 0xf1, 0xd1, 0x41, 0x61, 0xe1, 0x49, 0xf9, 0x79, 0x59, 0xc9, 0x51, 0x69, 0xd9, // 0x70
0x32, 0xaa, 0x82, 0xb2, 0x92, 0x02, 0x22, 0xa2, 0x0a, 0xba, 0x3a, 0x1a, 0x8a, 0x12, 0x2a, 0x9a, // 0x80
0x77, 0xef, 0xc7, 0xf7, 0xd7, 0x47, 0x67, 0xe7, 0x4f, 0xff, 0x7f, 0x5f, 0xcf, 0x57, 0x6f, 0xdf, // 0x90
0x37, 0xaf, 0x87, 0xb7, 0x97, 0x07, 0x27, 0xa7, 0x0f, 0xbf, 0x3f, 0x1f, 0x8f, 0x17, 0x2f, 0x9f, // 0xa0
0x36, 0xae, 0x86, 0xb6, 0x96, 0x06, 0x26, 0xa6, 0x0e, 0xbe, 0x3e, 0x1e, 0x8e, 0x16, 0x2e, 0x9e, // 0xb0
0x72, 0xea, 0xc2, 0xf2, 0xd2, 0x42, 0x62, 0xe2, 0x4a, 0xfa, 0x7a, 0x5a, 0xca, 0x52, 0x6a, 0xda, // 0xc0
0x34, 0xac, 0x84, 0xb4, 0x94, 0x04, 0x24, 0xa4, 0x0c, 0xbc, 0x3c, 0x1c, 0x8c, 0x14, 0x2c, 0x9c, // 0xd0
0x33, 0xab, 0x83, 0xb3, 0x93, 0x03, 0x23, 0xa3, 0x0b, 0xbb, 0x3b, 0x1b, 0x8b, 0x13, 0x2b, 0x9b, // 0xe0
0x76, 0xee, 0xc6, 0xf6, 0xd6, 0x46, 0x66, 0xe6, 0x4e, 0xfe, 0x7e, 0x5e, 0xce, 0x56, 0x6e, 0xde // 0xf0
static const uint8_t data_low[16] = {
0x30, 0xa8, 0x80, 0xb0, 0x90, 0x00, 0x20, 0xa0, 0x08, 0xb8, 0x38, 0x18, 0x88, 0x10, 0x28, 0x98
};
static const uint8_t data_high[16] = {
0x05, 0x43, 0x40, 0x45, 0x44, 0x00, 0x01, 0x41, 0x02, 0x47, 0x07, 0x06, 0x42, 0x04, 0x03, 0x46
};
for (int i = 0; i < 0x100000; i++)
{
int j = (address_tab_high[i >> 15] << 15) + (i & 0x7fc0) + address_tab_low[i & 0x3f];
dst[i] = data_table[src[j]];
dst[i] = data_high[src[j]>>4] | data_low[src[j]&0xf];
if (i >= 0x00000 && i < 0x10000) {
dst[i] = bitswap<8>(dst[i], 3, 1, 7, 0, 6, 4, 5, 2) ^ 0xff;