/* Xyonix *********************************************************************

driver by David Haywood and Stephh

Notes about the board:

Ram is 2x 6264 (near Z80) and 1x 6264 near UM6845. Xtal is verified 16.000MHz,
I can also see another special chip . PHILKO PK8801. chip looks about the same as a
TMS3615 (though i have no idea what the chip actually is). its located next to the
prom, the 2x 256k roms, and the 1x 6264 ram.
Dip SW is 1 x 8-position

on the PCB is an empty socket. written next to the socket is 68705P3. "oh no" you
say..... well, its unpopulated, so maybe it was never used?


TODO:
- there are some more unknown commands for the I/O chip

******************************************************************************/

#include "emu.h"
#include "cpu/z80/z80.h"
#include "sound/sn76496.h"
#include "includes/xyonix.h"


static WRITE8_HANDLER( xyonix_irqack_w )
{
	cputag_set_input_line(space->machine, "maincpu", 0, CLEAR_LINE);
}


/* Inputs ********************************************************************/

static void handle_coins(running_machine *machine, int coin)
{
	static const int coinage_table[4][2] = {{2,3},{2,1},{1,2},{1,1}};
	xyonix_state *state = (xyonix_state *)machine->driver_data;
	int tmp = 0;

	//popmessage("Coin %d", state->coin);

	if (coin & 1)	// Coin 2 !
	{
		tmp = (input_port_read(machine, "DSW") & 0xc0) >> 6;
		state->coins++;
		if (state->coins >= coinage_table[tmp][0])
		{
			state->credits += coinage_table[tmp][1];
			state->coins -= coinage_table[tmp][0];
		}
		coin_lockout_global_w(machine, 0); /* Unlock all coin slots */
		coin_counter_w(machine,1,1); coin_counter_w(machine,1,0); /* Count slot B */
	}

	if (coin & 2)	// Coin 1 !
	{
		tmp = (input_port_read(machine, "DSW") & 0x30) >> 4;
		state->coins++;
		if (state->coins >= coinage_table[tmp][0])
		{
			state->credits += coinage_table[tmp][1];
			state->coins -= coinage_table[tmp][0];
		}
		coin_lockout_global_w(machine, 0); /* Unlock all coin slots */
		coin_counter_w(machine,0,1); coin_counter_w(machine,0,0); /* Count slot A */
	}

	if (state->credits >= 9)
		state->credits = 9;
}


static READ8_HANDLER ( xyonix_io_r )
{
	xyonix_state *state = (xyonix_state *)space->machine->driver_data;
	int regPC = cpu_get_pc(space->cpu);

	if (regPC == 0x27ba)
		return 0x88;

	if (regPC == 0x27c2)
		return state->e0_data;

	if (regPC == 0x27c7)
	{
		int coin;

		switch (state->e0_data)
		{
			case 0x81 :
				return input_port_read(space->machine, "P1") & 0x7f;
			case 0x82 :
				return input_port_read(space->machine, "P2") & 0x7f;
			case 0x91:
				/* check coin inputs */
				coin = ((input_port_read(space->machine, "P1") & 0x80) >> 7) | ((input_port_read(space->machine, "P2") & 0x80) >> 6);
				if (coin ^ state->prev_coin && coin != 3)
				{
					if (state->credits < 9) handle_coins(space->machine, coin);
				}
				state->prev_coin = coin;
				return state->credits;
			case 0x92:
				return ((input_port_read(space->machine, "P1") & 0x80) >> 7) | ((input_port_read(space->machine, "P2") & 0x80) >> 6);
			case 0xe0:	/* reset? */
				state->coins = 0;
				state->credits = 0;
				return 0xff;
			case 0xe1:
				state->credits--;
				return 0xff;
			case 0xfe:	/* Dip Switches 1 to 4 */
				return input_port_read(space->machine, "DSW") & 0x0f;
			case 0xff:	/* Dip Switches 5 to 8 */
				return input_port_read(space->machine, "DSW") >> 4;
		}
	}

	//logerror ("xyonix_port_e0_r - PC = %04x - port = %02x\n", regPC, state->e0_data);
	//popmessage("%02x",state->e0_data);

	return 0xff;
}

static WRITE8_HANDLER ( xyonix_io_w )
{
	xyonix_state *state = (xyonix_state *)space->machine->driver_data;

	//logerror ("xyonix_port_e0_w %02x - PC = %04x\n", data, cpu_get_pc(space->cpu));
	state->e0_data = data;
}

/* Mem / Port Maps ***********************************************************/

static ADDRESS_MAP_START( main_map, ADDRESS_SPACE_PROGRAM, 8 )
	AM_RANGE(0x0000, 0xbfff) AM_ROM
	AM_RANGE(0xc000, 0xdfff) AM_RAM
	AM_RANGE(0xe000, 0xffff) AM_RAM_WRITE(xyonix_vidram_w) AM_BASE_MEMBER(xyonix_state,vidram)
ADDRESS_MAP_END

static ADDRESS_MAP_START( port_map, ADDRESS_SPACE_IO, 8 )
	ADDRESS_MAP_GLOBAL_MASK(0xff)
	AM_RANGE(0x20, 0x20) AM_READNOP AM_DEVWRITE("sn1", sn76496_w)	/* SN76496 ready signal */
	AM_RANGE(0x21, 0x21) AM_READNOP AM_DEVWRITE("sn2", sn76496_w)
	AM_RANGE(0x40, 0x40) AM_WRITENOP		/* NMI ack? */
	AM_RANGE(0x50, 0x50) AM_WRITE(xyonix_irqack_w)
	AM_RANGE(0x60, 0x61) AM_WRITENOP		/* mc6845 */
	AM_RANGE(0xe0, 0xe0) AM_READWRITE(xyonix_io_r, xyonix_io_w)
ADDRESS_MAP_END

/* Inputs Ports **************************************************************/

static INPUT_PORTS_START( xyonix )
	PORT_START("P1")
	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_8WAY PORT_PLAYER(1)
	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT ) PORT_8WAY PORT_PLAYER(1)
	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN ) PORT_8WAY PORT_PLAYER(1)
	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_UP ) PORT_8WAY PORT_PLAYER(1)
	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON2 ) PORT_PLAYER(1)
	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_PLAYER(1)
	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_START1 )
	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_COIN1 )		/* handled by xyonix_io_r() */

	PORT_START("P2")
	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_UP ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON2 ) PORT_PLAYER(2)
	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_PLAYER(2)
	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_START2 )
	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_COIN2 )		/* handled by xyonix_io_r() */

	PORT_START("DSW")
	PORT_DIPNAME( 0x03, 0x03, DEF_STR( Difficulty ) )
	PORT_DIPSETTING(    0x03, DEF_STR( Easy ) )
	PORT_DIPSETTING(    0x02, DEF_STR( Normal ) )
	PORT_DIPSETTING(    0x01, DEF_STR( Hard ) )
	PORT_DIPSETTING(    0x00, DEF_STR( Hardest ) )			// DEF_STR( Very_Hard )
	PORT_DIPNAME( 0x04, 0x00, DEF_STR( Allow_Continue ) )
	PORT_DIPSETTING(    0x04, DEF_STR( No ) )
	PORT_DIPSETTING(    0x00, DEF_STR( Yes ) )
	PORT_SERVICE( 0x08, IP_ACTIVE_LOW )
	PORT_DIPNAME( 0x30, 0x30, DEF_STR( Coin_A ) )
	PORT_DIPSETTING(    0x10, DEF_STR( 2C_1C ) )
	PORT_DIPSETTING(    0x30, DEF_STR( 1C_1C ) )
	PORT_DIPSETTING(    0x00, DEF_STR( 2C_3C ) )
	PORT_DIPSETTING(    0x20, DEF_STR( 1C_2C ) )
	PORT_DIPNAME( 0xc0, 0xc0, DEF_STR( Coin_B ) )
	PORT_DIPSETTING(    0x40, DEF_STR( 2C_1C ) )
	PORT_DIPSETTING(    0xc0, DEF_STR( 1C_1C ) )
	PORT_DIPSETTING(    0x00, DEF_STR( 2C_3C ) )
	PORT_DIPSETTING(    0x80, DEF_STR( 1C_2C ) )
INPUT_PORTS_END

/* GFX Decode ****************************************************************/

static const gfx_layout charlayout =
{
	4,8,
	RGN_FRAC(1,2),
	4,
	{ 0, 4, RGN_FRAC(1,2)+0, RGN_FRAC(1,2)+4 },
	{ 3, 2, 1, 0 },
	{ 0*8, 1*8, 2*8, 3*8, 4*8, 5*8, 6*8, 7*8 },
	4*16
};

static GFXDECODE_START( xyonix )
	GFXDECODE_ENTRY( "gfx1", 0, charlayout, 0, 16 )
GFXDECODE_END

/* MACHINE driver *************************************************************/

static MACHINE_DRIVER_START( xyonix )

	MDRV_DRIVER_DATA( xyonix_state )

	/* basic machine hardware */
	MDRV_CPU_ADD("maincpu", Z80,16000000 / 4)		 /* 4 MHz ? */
	MDRV_CPU_PROGRAM_MAP(main_map)
	MDRV_CPU_IO_MAP(port_map)
	MDRV_CPU_VBLANK_INT("screen", nmi_line_pulse)
	MDRV_CPU_PERIODIC_INT(irq0_line_assert,4*60)	/* ?? controls music tempo */

	/* video hardware */
	MDRV_SCREEN_ADD("screen", RASTER)
	MDRV_SCREEN_REFRESH_RATE(60)
	MDRV_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
	MDRV_SCREEN_FORMAT(BITMAP_FORMAT_INDEXED16)
	MDRV_SCREEN_SIZE(80*4, 32*8)
	MDRV_SCREEN_VISIBLE_AREA(0, 80*4-1, 0, 28*8-1)

	MDRV_GFXDECODE(xyonix)
	MDRV_PALETTE_LENGTH(256)

	MDRV_PALETTE_INIT(xyonix)
	MDRV_VIDEO_START(xyonix)
	MDRV_VIDEO_UPDATE(xyonix)

	/* sound hardware */
	MDRV_SPEAKER_STANDARD_MONO("mono")

	MDRV_SOUND_ADD("sn1", SN76496, 16000000/4)
	MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0)

	MDRV_SOUND_ADD("sn2", SN76496, 16000000/4)
	MDRV_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0)
MACHINE_DRIVER_END

/* ROM Loading ***************************************************************/

ROM_START( xyonix )
	ROM_REGION( 0x10000, "maincpu", 0 )
	ROM_LOAD( "xyonix3.bin", 0x00000, 0x10000, CRC(1960a74e) SHA1(5fd7bc31ca2f5f1e114d3d0ccf6554ebd712cbd3) )

	ROM_REGION( 0x10000, "gfx1", 0 )
	ROM_LOAD( "xyonix1.bin", 0x00000, 0x08000, CRC(3dfa9596) SHA1(52cdbbe18f83cea7248c29588ea3a18c4bb7984f) )
	ROM_LOAD( "xyonix2.bin", 0x08000, 0x08000, CRC(db87343e) SHA1(62bc30cd65b2f8976cd73a0b349a9ccdb3faaad2) )

	ROM_REGION( 0x0100, "proms", 0 )
	ROM_LOAD( "xyonix.pr",   0x0000, 0x0100, CRC(0012cfc9) SHA1(c7454107a1a8083a370b662c617117b769c0dc1c) )
ROM_END

/* GAME drivers **************************************************************/

GAME( 1989, xyonix, 0, xyonix, xyonix, 0, ROT0, "Philko", "Xyonix", 0 )
