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small step towards getting rid of the cps2_dead machine config. (nw)

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This commit is contained in:
smf- 2016-09-19 11:28:02 +01:00
parent a96e3c1712
commit ea15eb9111
2 changed files with 16 additions and 16 deletions
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1
src/mame/drivers/cps2.cpp
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@ -1342,7 +1342,6 @@ static MACHINE_CONFIG_DERIVED( dead_cps2, cps2 )
MCFG_CPU_MODIFY("maincpu") MCFG_CPU_MODIFY("maincpu")
MCFG_CPU_PROGRAM_MAP(dead_cps2_map) MCFG_CPU_PROGRAM_MAP(dead_cps2_map)
MCFG_DEVICE_REMOVE_ADDRESS_MAP(AS_DECRYPTED_OPCODES)
MACHINE_CONFIG_END MACHINE_CONFIG_END
static MACHINE_CONFIG_DERIVED( gigaman2, cps2 ) static MACHINE_CONFIG_DERIVED( gigaman2, cps2 )

31
src/mame/machine/cps2crypt.cpp
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@ -704,17 +704,18 @@ static void cps2_decrypt(running_machine &machine, UINT16 *rom, UINT16 *dec, int
// decrypt the opcodes // decrypt the opcodes
for (a = i; a < length/2 && a < upper_limit/2; a += 0x10000) for (a = i; a < length/2; a += 0x10000)
{ {
dec[a] = feistel(rom[a], fn2_groupA, fn2_groupB, if (a >= lower_limit && a <= upper_limit)
&sboxes2[0*4], &sboxes2[1*4], &sboxes2[2*4], &sboxes2[3*4], {
key2[0], key2[1], key2[2], key2[3]); dec[a] = feistel(rom[a], fn2_groupA, fn2_groupB,
} &sboxes2[0 * 4], &sboxes2[1 * 4], &sboxes2[2 * 4], &sboxes2[3 * 4],
// copy the unencrypted part key2[0], key2[1], key2[2], key2[3]);
while (a < length/2) }
{ else
dec[a] = rom[a]; {
a += 0x10000; dec[a] = rom[a];
}
} }
} }
} }
@ -774,18 +775,18 @@ DRIVER_INIT_MEMBER(cps_state,cps2crypt)
{ {
// On a dead board, the only encrypted range is actually FF0000-FFFFFF. // On a dead board, the only encrypted range is actually FF0000-FFFFFF.
// It doesn't start from 0, and it's the upper half of a 128kB bank. // It doesn't start from 0, and it's the upper half of a 128kB bank.
upper = 0xffffffff; upper = 0xffffff;
lower = 0xff0000; lower = 0xff0000;
} }
else else
{ {
// This matches two thirds of the old values upper = (((~decoded[9] & 0x3ff) << 14) | 0x3fff) + 1;
upper = (((decoded[9] ^ 0x3f0) << 14) | 0x3ffff) + 1;
lower = 0; lower = 0;
} }
logerror("cps2 decrypt 0x%08x,0x%08x,0x%08x,0x%08x\n", key[0], key[1], lower, upper);
// we have a proper key so use it to decrypt // we have a proper key so use it to decrypt
if (lower != 0xff0000) // don't run the decrypt on 'dead key' games for now cps2_decrypt(machine(), (UINT16 *)memregion("maincpu")->base(), m_decrypted_opcodes, memregion("maincpu")->bytes(), key, lower / 2, upper / 2);
cps2_decrypt(machine(), (UINT16 *)memregion("maincpu")->base(), m_decrypted_opcodes, memregion("maincpu")->bytes(), key, lower, upper);
} }
} }