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simplified expro02 decryption

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This commit is contained in:
Nicola Salmoria 2008-10-10 07:14:10 +00:00
parent fa433938c0
commit 33f6cb5d84
1 changed files with 34 additions and 61 deletions
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95
src/mame/drivers/expro02.c
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@ -472,68 +472,7 @@ static MACHINE_DRIVER_START( galsnew )
MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0) MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0)
MACHINE_DRIVER_END MACHINE_DRIVER_END
/* the tile roms seem lineswapped.. but I don't know how to descramble them yet */
DRIVER_INIT(galsnew)
{
UINT32 *src = (UINT32 *)memory_region(machine, "gfx3" );
UINT32 *dst = (UINT32 *)memory_region(machine, "gfx2" );
int x, source, offset,inv;
for (x=0; x<0x80000;x++)
{
inv = ~x;
offset = x ^ (0xC30 | (inv >> 1 & 0x10200));
offset = (offset & ~0x07) | ((0x02 - (offset & 0x07)) & 0x07);
if(x&0x0010)
offset = (offset & ~0x60) | (((offset & 0x60) + 0x20) & 0x60);
if((x&((inv >> 1 & 0x10000) | 0x2000)) == 0x02000)
offset ^= 0x1000;
if(!(x&(0x1000 | (x >> 4 & 0x2000))))
{
offset ^= 0x100;
if(!(x&0x20000) && (x&0x12000) == 0x02000)
{
offset = (offset & ~0x180) | (((offset & 0x180) + 0x180) & 0x180);
if((x&0x180) == 0x100)
{
offset ^= 0x400;
if((x&0x480) == 0x400)
offset ^= 0x200;
}
}
}
else
{
offset = (offset & ~0x180) | (((offset & 0x180) + 0x80) & 0x180);
if((x&0x180) == 0x100)
{
offset ^= 0x400;
if((x&0x480) == 0x400)
offset ^= 0x200;
}
}
if((x&0x7) < 0x03)
{
if(!(x&0x800))
{
offset ^= 0x4000;
if(x&0x4000)
{
offset ^= 0x08;
if(x&0x08)
offset = (offset & ~0x70) | (((offset & 0x70) + 0x10) & 0x70);
}
}
offset ^= 0x800;
}
if((x & 0x30000) == 0x10000)
source = x;
else
source = x ^ 0x2000;
dst[source] = (src[offset] << 4 & 0xF0F0F0F0) | (src[offset] >> 4 & 0x0F0F0F0F);
}
}
ROM_START( galsnew ) /* EXPRO-02 PCB */ ROM_START( galsnew ) /* EXPRO-02 PCB */
ROM_REGION( 0x40000, "main", 0 ) /* 68000 code */ ROM_REGION( 0x40000, "main", 0 ) /* 68000 code */
@ -653,6 +592,40 @@ ROM_START( galsnewj ) /* EXPRO-02 PCB */
ROM_END ROM_END
DRIVER_INIT(galsnew)
{
UINT32 *src = (UINT32 *)memory_region(machine, "gfx3" );
UINT32 *dst = (UINT32 *)memory_region(machine, "gfx2" );
int x, offset;
for (x = 0; x < 0x80000; x++)
{
offset = x;
// swap bits around to simplify further processing
offset = BITSWAP24(offset, 23,22,21,20,19, 18,15, 9,10,8,7,12,13,16,17, 6,5,4,3,14,11,2,1,0);
// invert 8 bits
offset ^= 0x0528f;
// addition affecting 9 bits
offset = (offset & ~0x001ff) | ((offset + 0x00043) & 0x001ff);
// subtraction affecting 8 bits
offset = (offset & ~0x1fe00) | ((offset - 0x09600) & 0x1fe00);
// reverse the initial bitswap
offset = BITSWAP24(offset, 23,22,21,20,19, 18,9,10,17,4,11,12,3,15,16,14,13,8,7,6,5,2,1,0);
// swap nibbles to use the same gfxdecode
dst[x] = (src[offset] << 4 & 0xF0F0F0F0) | (src[offset] >> 4 & 0x0F0F0F0F);
}
}
GAME( 1990, galsnew, 0, galsnew, galsnew, galsnew, ROT90, "Kaneko", "Gals Panic (US, EXPRO-02 PCB)", 0 ) GAME( 1990, galsnew, 0, galsnew, galsnew, galsnew, ROT90, "Kaneko", "Gals Panic (US, EXPRO-02 PCB)", 0 )
GAME( 1990, galsnewa, galsnew, galsnew, galsnewa, galsnew, ROT90, "Kaneko", "Gals Panic (Export, EXPRO-02 PCB)", 0 ) GAME( 1990, galsnewa, galsnew, galsnew, galsnewa, galsnew, ROT90, "Kaneko", "Gals Panic (Export, EXPRO-02 PCB)", 0 )
GAME( 1990, galsnewj, galsnew, galsnew, galsnewa, galsnew, ROT90, "Kaneko (Taito license)", "Gals Panic (Japan, EXPRO-02 PCB)", 0 ) GAME( 1990, galsnewj, galsnew, galsnew, galsnewa, galsnew, ROT90, "Kaneko (Taito license)", "Gals Panic (Japan, EXPRO-02 PCB)", 0 )