From ad1f309d08aafbe412ca42f8b8e3ef8ded119aa4 Mon Sep 17 00:00:00 2001 From: Angelo Salese Date: Sat, 15 Nov 2014 15:42:37 +0100 Subject: Added f/f mechanism for irq, game works (lol?), added information about a very crude protection mechanism. --- src/mame/drivers/alinvade.c | 42 +++++++++++++++++++++++++++++------------- 1 file changed, 29 insertions(+), 13 deletions(-) diff --git a/src/mame/drivers/alinvade.c b/src/mame/drivers/alinvade.c index 542f472cff5..2a47f44a7b6 100644 --- a/src/mame/drivers/alinvade.c +++ b/src/mame/drivers/alinvade.c @@ -4,7 +4,11 @@ does it use any off-the shelf chips in addition to the 6502? - + TODO: + - 16 bytes are protected in the c*** range. I'm guessing they used a PROM to protect a + simple sub-routine because just after that the program has a left-over located at 0xe000-0xe00f (yup, NOPs + a RTS) + It's unknown at current stage what it really protects tho ... + */ #include "emu.h" @@ -20,6 +24,8 @@ public: { } UINT8 irqmask; + UINT8 irqff; + DECLARE_READ8_MEMBER(irqmask_r); DECLARE_WRITE8_MEMBER(irqmask_w); INTERRUPT_GEN_MEMBER(vblank_irq); required_device m_maincpu; @@ -31,9 +37,18 @@ public: UINT32 screen_update_alinvade(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect); }; +READ8_MEMBER(alinvade_state::irqmask_r) +{ + return 0; // TODO: might be anything +} + + WRITE8_MEMBER(alinvade_state::irqmask_w) { - irqmask = data; + if((!(irqff & 1)) && (data & 1)) // f/f, active high? If the above actually returns 0xff this could be active low ... + irqmask^= 1; + + irqff = data; } static ADDRESS_MAP_START( alinvade_map, AS_PROGRAM, 8, alinvade_state ) @@ -49,11 +64,10 @@ static ADDRESS_MAP_START( alinvade_map, AS_PROGRAM, 8, alinvade_state ) AM_RANGE(0x8003, 0x8003) AM_READ_PORT("IN3") AM_RANGE(0x8004, 0x8004) AM_READ_PORT("IN4") AM_RANGE(0xa000, 0xa000) AM_WRITENOP //?? - AM_RANGE(0xc400, 0xc7ff) AM_ROM - AM_RANGE(0xc800, 0xcbff) AM_ROM + AM_RANGE(0xc000, 0xc00f) AM_MIRROR(0xff0) AM_ROM AM_REGION("proms",0) AM_RANGE(0xe000, 0xe3ff) AM_ROM - AM_RANGE(0xe400, 0xe400) AM_WRITE(irqmask_w) //?? - AM_RANGE(0xe800, 0xe800) AM_READNOP AM_WRITENOP //?? + AM_RANGE(0xe400, 0xe400) AM_WRITENOP //?? + AM_RANGE(0xe800, 0xe800) AM_READWRITE(irqmask_r,irqmask_w) //?? AM_RANGE(0xec00, 0xffff) AM_ROM ADDRESS_MAP_END @@ -102,6 +116,7 @@ void alinvade_state::machine_start() void alinvade_state::machine_reset() { + irqmask = 1; } UINT32 alinvade_state::screen_update_alinvade(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect) @@ -136,9 +151,6 @@ INTERRUPT_GEN_MEMBER(alinvade_state::vblank_irq) m_maincpu->set_input_line(0,HOLD_LINE); } - - - static MACHINE_CONFIG_START( alinvade, alinvade_state ) /* basic machine hardware */ @@ -154,6 +166,8 @@ static MACHINE_CONFIG_START( alinvade, alinvade_state ) MCFG_SCREEN_VISIBLE_AREA(0, 128-1, 0, 128-1) MCFG_SCREEN_UPDATE_DRIVER(alinvade_state, screen_update_alinvade) + // TODO: MCFG_DEFAULT_LAYOUT for square pixels + /* sound hardware */ MCFG_SPEAKER_STANDARD_MONO("mono") MACHINE_CONFIG_END @@ -162,16 +176,18 @@ MACHINE_CONFIG_END ROM_START( alinvade ) ROM_REGION( 0x10000, "maincpu", 0 ) // todo, check mapping - - ROM_FILL( 0xc400, 0x800, 0x60 ) // rts for whole area, interrupt code jumps to various addresses here - ROM_LOAD( "alien28.708", 0xe000, 0x0400, CRC(de376295) SHA1(e8eddbb1be1f8661c6b5b39c0d78a65bded65db2) ) ROM_LOAD( "alien29.708", 0xec00, 0x0400, CRC(20212977) SHA1(9d24a6b403d968267079fa6241545bd5a01afebb) ) ROM_LOAD( "alien30.708", 0xf000, 0x0400, CRC(734b691c) SHA1(9e562159061eecf4b1dee4ea0ee4752c901a54aa) ) ROM_LOAD( "alien31.708", 0xf400, 0x0400, CRC(5a70535c) SHA1(2827e7d4bffca78bd035da04481e1e972ee2da39) ) ROM_LOAD( "alien32.708", 0xf800, 0x0400, CRC(332dd234) SHA1(9974668344a2a351868a9e7757d1c3a497dc5621) ) ROM_LOAD( "alien33.708", 0xfc00, 0x0400, CRC(e0d57fc7) SHA1(7b8ddcb4a86811592d2d0bbc61b2f19e5caa9ccc) ) + + ROM_REGION( 0x20, "proms", 0 ) + ROM_LOAD( "prom", 0, 0x20, NO_DUMP ) + ROM_FILL( 0x00, 0x0f, 0xea ) + ROM_FILL( 0x0f, 0x01, 0x60 ) // rts for whole area, interrupt code jumps to various addresses here, check note on top. ROM_END -GAME( 198?, alinvade, 0, alinvade, alinvade, driver_device, 0, ROT90, "Forbes?", "Alien Invaders", GAME_NOT_WORKING ) +GAME( 198?, alinvade, 0, alinvade, alinvade, driver_device, 0, ROT90, "Forbes?", "Alien Invaders", GAME_UNEMULATED_PROTECTION ) -- cgit v1.2.3