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Emulated Lord of Gun's protection rather than patching it out [iq_132]

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This commit is contained in:
Miodrag Milanovic 2012-10-08 06:25:43 +00:00
parent c683bc7181
commit f20c31a065
2 changed files with 50 additions and 7 deletions
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53
src/mame/drivers/lordgun.c
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@ -71,11 +71,6 @@ DRIVER_INIT_MEMBER(lordgun_state,lordgun)
rom[i] = x;
}
// Protection
rom[0x14832/2] = 0x6000; // 014832: 6700 0006 beq $1483a (protection)
rom[0x1587e/2] = 0x6010; // 01587E: 6710 beq $15890 (rom check)
}
@ -134,6 +129,50 @@ DRIVER_INIT_MEMBER(lordgun_state,alienchac)
***************************************************************************/
WRITE16_MEMBER(lordgun_state::lordgun_protection_w)
{
switch (offset & 0x60)
{
// The data written to offsets 0 - 1f is offset * 2
// Use this write to increment the counter.
case 0x00:
m_lordgun_protection_data++;
return;
case 0x20: // unused?
case 0x40: // protection results are read back from 40-5f.
return;
case 0x60: // reset / init
m_lordgun_protection_data = 0;
return;
}
}
READ16_MEMBER(lordgun_state::lordgun_protection_r)
{
// Other offset ranges are not used?
if ((offset & 0x60) == 0x40)
{
// Check to see if counter meets various conditions.
// The results may not be 0010, but this is the only bit
// that is checked by the 68k.
if ((m_lordgun_protection_data & 0x11) == 0x01)
return 0x0010;
if ((m_lordgun_protection_data & 0x06) == 0x02)
return 0x0010;
if ((m_lordgun_protection_data & 0x09) == 0x08)
return 0x0010;
return 0;
}
return 0;
}
WRITE8_MEMBER(lordgun_state::fake_w)
{
}
@ -286,7 +325,7 @@ static ADDRESS_MAP_START( lordgun_map, AS_PROGRAM, 16, lordgun_state )
AM_RANGE(0x504000, 0x504001) AM_WRITE(lordgun_soundlatch_w)
AM_RANGE(0x506000, 0x506007) AM_DEVREADWRITE8("ppi8255_0", i8255_device, read, write, 0x00ff)
AM_RANGE(0x508000, 0x508007) AM_DEVREADWRITE8("ppi8255_1", i8255_device, read, write, 0x00ff)
AM_RANGE(0x50a900, 0x50a9ff) AM_RAM // protection
AM_RANGE(0x50a900, 0x50a9ff) AM_READWRITE(lordgun_protection_r, lordgun_protection_w)
ADDRESS_MAP_END
@ -1039,6 +1078,6 @@ ROM_END
***************************************************************************/
GAME( 1994, lordgun, 0, lordgun, lordgun, lordgun_state, lordgun, ROT0, "IGS", "Lord of Gun (USA)", GAME_UNEMULATED_PROTECTION | GAME_IMPERFECT_GRAPHICS )
GAME( 1994, lordgun, 0, lordgun, lordgun, lordgun_state, lordgun, ROT0, "IGS", "Lord of Gun (USA)", GAME_IMPERFECT_GRAPHICS )
GAME( 1994, aliencha, 0, aliencha, aliencha, lordgun_state, aliencha, ROT0, "IGS", "Alien Challenge (World)", GAME_UNEMULATED_PROTECTION )
GAME( 1994, alienchac, aliencha, aliencha, aliencha, lordgun_state, alienchac, ROT0, "IGS", "Alien Challenge (China)", GAME_UNEMULATED_PROTECTION )

4
src/mame/includes/lordgun.h
View File

@ -37,6 +37,10 @@ public:
tilemap_t *m_tilemap[4];
bitmap_ind16 *m_bitmaps[5];
UINT16 m_lordgun_protection_data;
DECLARE_WRITE16_MEMBER(lordgun_protection_w);
DECLARE_READ16_MEMBER(lordgun_protection_r);
DECLARE_WRITE16_MEMBER(lordgun_priority_w);
DECLARE_READ16_MEMBER(lordgun_gun_0_x_r);
DECLARE_READ16_MEMBER(lordgun_gun_0_y_r);