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metlfrzr encryption is the same as cshooter.cpp [Peter Wilhelmsen]

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This commit is contained in:
David Haywood 2016-05-13 13:52:23 +01:00
parent 6abc4b2970
commit dfa1577df0
1 changed files with 29 additions and 14 deletions
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43
src/mame/drivers/metlfrzr.cpp
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@ -15,7 +15,8 @@ class metlfrzr_state : public driver_device
public:
metlfrzr_state(const machine_config &mconfig, device_type type, const char *tag)
: driver_device(mconfig, type, tag),
m_maincpu(*this, "maincpu")
m_maincpu(*this, "maincpu"),
m_decrypted_opcodes(*this, "decrypted_opcodes")
{ }
virtual void machine_start() override;
@ -23,6 +24,7 @@ public:
virtual void video_start() override;
UINT32 screen_update_metlfrzr(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);
required_device<cpu_device> m_maincpu;
required_shared_ptr<UINT8> m_decrypted_opcodes;
DECLARE_DRIVER_INIT(metlfrzr);
};
@ -42,6 +44,10 @@ static ADDRESS_MAP_START( metlfrzr_map, AS_PROGRAM, 8, metlfrzr_state )
AM_RANGE(0x0000, 0x7fff) AM_ROM
ADDRESS_MAP_END
static ADDRESS_MAP_START( decrypted_opcodes_map, AS_DECRYPTED_OPCODES, 8, metlfrzr_state )
AM_RANGE(0x0000, 0x7fff) AM_ROM AM_SHARE("decrypted_opcodes")
ADDRESS_MAP_END
static INPUT_PORTS_START( metlfrzr )
INPUT_PORTS_END
@ -96,6 +102,7 @@ static MACHINE_CONFIG_START(metlfrzr, metlfrzr_state)
/* basic machine hardware */
MCFG_CPU_ADD("maincpu", Z80, XTAL_12MHz / 2)
MCFG_CPU_PROGRAM_MAP(metlfrzr_map)
MCFG_CPU_DECRYPTED_OPCODES_MAP(decrypted_opcodes_map)
// MCFG_CPU_VBLANK_INT_DRIVER("screen", metlfrzr_state, irq0_line_hold)
MCFG_DEVICE_ADD("t5182", T5182, 0)
@ -164,24 +171,32 @@ ROM_END
DRIVER_INIT_MEMBER(metlfrzr_state, metlfrzr)
{
UINT8 *ROM = memregion("maincpu")->base();
// same as cshooter.cpp
UINT8 *rom = memregion("maincpu")->base();
for (int i = 0;i < 0x8000;i++)
for (int A = 0x0000;A < 0x8000;A++)
{
/* decode the opcodes */
m_decrypted_opcodes[A] = rom[A];
if (BIT(A,5) && !BIT(A,3))
m_decrypted_opcodes[A] ^= 0x40;
if ( (i & 0x20) == 0x20)
{
ROM[i] ^= 0x40;
if (BIT(A,10) && !BIT(A,9) && BIT(A,3))
m_decrypted_opcodes[A] ^= 0x20;
}
else
{
// 61 70 45 44 49 54
// to
// 43 52 45 44 49 54
ROM[i] = BITSWAP8(ROM[i], 7, 6, 1, 4, 3, 2, 5, 0);
}
if ((BIT(A,10) ^ BIT(A,9)) && BIT(A,1))
m_decrypted_opcodes[A] ^= 0x02;
if (BIT(A,9) || !BIT(A,5) || BIT(A,3))
m_decrypted_opcodes[A] = BITSWAP8(m_decrypted_opcodes[A],7,6,1,4,3,2,5,0);
/* decode the data */
if (BIT(A,5))
rom[A] ^= 0x40;
if (BIT(A,9) || !BIT(A,5))
rom[A] = BITSWAP8(rom[A],7,6,1,4,3,2,5,0);
}
}