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4roses: Further progress on decryption (nw)

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This commit is contained in:
AJR 2018-03-30 23:31:59 -04:00
parent a0dc658589
commit 625c8533ad
1 changed files with 19 additions and 3 deletions
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22
src/mame/drivers/4roses.cpp
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@ -237,10 +237,26 @@ void _4roses_state::_4roses_map(address_map &map)
READ8_MEMBER(_4roses_state::_4roses_opcode_r)
{
uint8_t data = m_maincpu->space(AS_PROGRAM).read_byte(offset);
if ((offset & 0x7c00) == 0x6400)
data = bitswap<8>(data ^ 0x3f, 3, 4, 2, 5, 1, 6, 0, 7);
else if ((offset & 0x7c00) == 0x6000)
switch (offset & 0x7c00)
{
case 0x6000:
data = bitswap<8>(data ^ 0x68, 4, 3, 2, 1, 0, 7, 6, 5);
break;
case 0x6400:
data = bitswap<8>(data ^ 0x3f, 3, 4, 2, 5, 1, 6, 0, 7);
break;
case 0x6800:
data = bitswap<8>(data ^ 0x6a, 7, 0, 2, 1, 4, 3, 6, 5);
break;
case 0x6c00:
data = bitswap<8>(data ^ 0x5e, 6, 1, 4, 5, 2, 3, 0, 7);
break;
}
return data;
}