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Diffstat (limited to 'src/mame/drivers/alinvade.cpp')
-rw-r--r-- | src/mame/drivers/alinvade.cpp | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/src/mame/drivers/alinvade.cpp b/src/mame/drivers/alinvade.cpp new file mode 100644 index 00000000000..3ce130711fe --- /dev/null +++ b/src/mame/drivers/alinvade.cpp @@ -0,0 +1,240 @@ +// license:BSD-3-Clause +// copyright-holders:David Haywood, Mariusz Wojcieszek +/* + + tiny bartop b&w Space Invaders type game with colour overlay + + Driver by David Haywood and Mariusz Wojcieszek + + TODO: + - 16 bytes are protected in the c*** range. I'm guessing they used a PROM to protect a + simple sub-routine because: + * It attempts to jsr from RAM to that area with a 0x10 byte offset (i.e. ROM copies a code snippet to RAM; when it executes + it code executes jsr 0xc400 then self-modifies it to 0xc410, rinse and repeat ... up to 0xc7f0 and rolls back); + * After that the program has an amusing left-over located at 0xe000-0xe00f (yup, NOPs + a RTS), with the + exact same number of times as above; + It's unknown at current stage what it really protects tho, game seems working for all I can see ... -AS + + - Sound is entirely guesswork. + + */ + +#include "emu.h" +#include "cpu/m6502/m6502.h" +#include "sound/discrete.h" +#include "alinvade.lh" + +class alinvade_state : public driver_device +{ +public: + alinvade_state(const machine_config &mconfig, device_type type, const char *tag) + : driver_device(mconfig, type, tag) + , m_maincpu(*this, "maincpu") + , m_videoram(*this, "videoram") + , m_discrete(*this, "discrete") + { } + + DECLARE_READ8_MEMBER(irqmask_r); + DECLARE_WRITE8_MEMBER(irqmask_w); + DECLARE_WRITE8_MEMBER(sound_w); + DECLARE_WRITE8_MEMBER(sounden_w); + INTERRUPT_GEN_MEMBER(vblank_irq); + UINT32 screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect); + +private: + UINT8 m_irqmask; + UINT8 m_irqff; + virtual void machine_start(); + virtual void machine_reset(); + required_device<cpu_device> m_maincpu; + required_shared_ptr<UINT8> m_videoram; + required_device<discrete_device> m_discrete; +}; + +static const discrete_dac_r1_ladder alinvade_music_dac = + {3, {0, RES_K(47), RES_K(12)}, 0, 0, 0, CAP_U(0.01)}; + +#define ALINVADE_MUSIC_CLK (75000) + +DISCRETE_SOUND_START(alinvade) + DISCRETE_INPUT_DATA (NODE_01) + + DISCRETE_NOTE(NODE_20, 1, ALINVADE_MUSIC_CLK, NODE_01, 255, 5, DISC_CLK_IS_FREQ) + + // Convert count to 7492 output + DISCRETE_TRANSFORM2(NODE_21, NODE_20, 2, "01>0+") + + DISCRETE_DAC_R1(NODE_22, NODE_21, DEFAULT_TTL_V_LOGIC_1, &alinvade_music_dac) + + DISCRETE_CRFILTER(NODE_80, NODE_22, RES_K(10), CAP_U(0.1)) + + DISCRETE_OUTPUT(NODE_80, 2500) + +DISCRETE_SOUND_END + +WRITE8_MEMBER( alinvade_state::sound_w ) +{ + m_discrete->write(space, NODE_01, (data^0x3f)<<2); +} + +WRITE8_MEMBER( alinvade_state::sounden_w ) +{ + machine().sound().system_enable(data == 4); +} + +READ8_MEMBER(alinvade_state::irqmask_r) +{ + return 0; // TODO: might be anything +} + + +WRITE8_MEMBER(alinvade_state::irqmask_w) +{ + if((!(m_irqff & 1)) && (data & 1)) // f/f, active high? If the above actually returns 0xff this could be active low ... + m_irqmask^= 1; + + m_irqff = data; +} + +static ADDRESS_MAP_START( alinvade_map, AS_PROGRAM, 8, alinvade_state ) + AM_RANGE(0x0000, 0x01ff) AM_RAM + AM_RANGE(0x0400, 0x0bff) AM_RAM AM_SHARE("videoram") + AM_RANGE(0x0c00, 0x0dff) AM_RAM + AM_RANGE(0x2000, 0x2000) AM_WRITE(sound_w) + AM_RANGE(0x4000, 0x4000) AM_READ_PORT("COIN") + AM_RANGE(0x6000, 0x6000) AM_READ_PORT("DSW") + AM_RANGE(0x8000, 0x8000) AM_READ_PORT("IN0") + AM_RANGE(0x8001, 0x8001) AM_READ_PORT("IN1") + AM_RANGE(0x8002, 0x8002) AM_READ_PORT("IN2") + AM_RANGE(0x8003, 0x8003) AM_READ_PORT("IN3") + AM_RANGE(0x8004, 0x8004) AM_READ_PORT("IN4") + AM_RANGE(0xa000, 0xa000) AM_WRITENOP //?? + 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(sounden_w) + AM_RANGE(0xe800, 0xe800) AM_READWRITE(irqmask_r,irqmask_w) //?? + AM_RANGE(0xec00, 0xffff) AM_ROM +ADDRESS_MAP_END + + +static INPUT_PORTS_START( alinvade ) + PORT_START("COIN") + PORT_BIT(0x10, IP_ACTIVE_LOW, IPT_COIN1 ) + PORT_BIT(0xef, IP_ACTIVE_LOW, IPT_UNKNOWN ) + + PORT_START("IN0") + PORT_BIT(0x20, IP_ACTIVE_HIGH, IPT_BUTTON1 ) PORT_PLAYER(1) + PORT_BIT(0xdf, IP_ACTIVE_HIGH, IPT_UNKNOWN ) + + PORT_START("IN1") + PORT_BIT(0x20, IP_ACTIVE_HIGH, IPT_JOYSTICK_RIGHT ) PORT_2WAY PORT_PLAYER(1) + PORT_BIT(0xdf, IP_ACTIVE_HIGH, IPT_UNKNOWN ) + + PORT_START("IN2") + PORT_BIT(0x20, IP_ACTIVE_HIGH, IPT_JOYSTICK_LEFT ) PORT_2WAY PORT_PLAYER(1) + PORT_BIT(0xdf, IP_ACTIVE_HIGH, IPT_UNKNOWN ) + + PORT_START("IN3") + PORT_BIT(0x20, IP_ACTIVE_HIGH, IPT_START1 ) + PORT_BIT(0xdf, IP_ACTIVE_HIGH, IPT_UNKNOWN ) + + PORT_START("IN4") + PORT_BIT(0x20, IP_ACTIVE_HIGH, IPT_START2 ) + PORT_BIT(0xdf, IP_ACTIVE_HIGH, IPT_UNKNOWN ) + + PORT_START("DSW") + PORT_DIPNAME( 0x03, 0x00, DEF_STR( Lives ) ) + PORT_DIPSETTING( 0x00, "2" ) + PORT_DIPSETTING( 0x01, "3" ) + PORT_DIPSETTING( 0x02, "4" ) + PORT_DIPSETTING( 0x03, "5" ) + PORT_DIPNAME( 0x04, 0x00, DEF_STR ( Unknown ) ) // read, but not tested afterwards? + PORT_DIPSETTING( 0x00, DEF_STR( Off ) ) + PORT_DIPSETTING( 0x04, DEF_STR( On ) ) + PORT_BIT( 0xf8, IP_ACTIVE_HIGH, IPT_UNUSED ) +INPUT_PORTS_END + + +void alinvade_state::machine_start() +{ + save_item(NAME(m_irqff)); + save_item(NAME(m_irqmask)); +} + +void alinvade_state::machine_reset() +{ + m_irqmask = 1; +} + +UINT32 alinvade_state::screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect) +{ + offs_t offs; + + for (offs = 0; offs < m_videoram.bytes(); offs++) + { + int i; + + UINT8 x = (offs << 3)&0x7f; + int y = (offs >> 4)&0x7f; + UINT8 data = m_videoram[offs]; + + for (i = 0; i < 8; i++) + { + pen_t pen = (data & 0x01) ? rgb_t::white : rgb_t::black; + bitmap.pix32(y, x) = pen; + + data = data >> 1; + x = x + 1; + } + } + + + return 0; +} + +INTERRUPT_GEN_MEMBER(alinvade_state::vblank_irq) +{ + if(m_irqmask & 1) + m_maincpu->set_input_line(0,HOLD_LINE); +} + +static MACHINE_CONFIG_START( alinvade, alinvade_state ) + + /* basic machine hardware */ + MCFG_CPU_ADD("maincpu", M6502,2000000) /* ? MHz */ + MCFG_CPU_PROGRAM_MAP(alinvade_map) + MCFG_CPU_VBLANK_INT_DRIVER("screen", alinvade_state, vblank_irq) + + /* video hardware */ + MCFG_SCREEN_ADD("screen", RASTER) + MCFG_SCREEN_REFRESH_RATE(60) + MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0)) + MCFG_SCREEN_SIZE(128, 128) + MCFG_SCREEN_VISIBLE_AREA(0, 128-1, 0, 128-1) + MCFG_SCREEN_UPDATE_DRIVER(alinvade_state, screen_update) + + /* sound hardware */ + MCFG_SPEAKER_STANDARD_MONO("mono") + MCFG_DISCRETE_ADD("discrete", 0, alinvade) + MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0) +MACHINE_CONFIG_END + + + +ROM_START( alinvade ) + ROM_REGION( 0x10000, "maincpu", 0 ) // todo, check mapping + 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 + + +GAMEL( 198?, alinvade, 0, alinvade, alinvade, driver_device, 0, ROT90, "Forbes?", "Alien Invaders", MACHINE_UNEMULATED_PROTECTION | MACHINE_IMPERFECT_SOUND | MACHINE_SUPPORTS_SAVE, layout_alinvade ) |