// license:BSD-3-Clause
// copyright-holders:Manuel Abadia
/***************************************************************************

Glass (c) 1993 Gaelco (Developed by OMK. Produced by Gaelco)

Driver by Manuel Abadia <emumanu+mame@gmail.com>

The DS5002FP has up to 128KB undumped gameplay code making the game unplayable,
except for the Promat licensed Korean version which is unprotected.

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

#include "emu.h"
#include "cpu/m68000/m68000.h"
#include "sound/okim6295.h"
#include "includes/glass.h"

WRITE16_MEMBER(glass_state::clr_int_w)
{
	m_cause_interrupt = 1;
}

INTERRUPT_GEN_MEMBER(glass_state::interrupt)
{
	if (m_cause_interrupt)
	{
		device.execute().set_input_line(6, HOLD_LINE);
		m_cause_interrupt = 0;
	}
}


static const gfx_layout glass_tilelayout16 =
{
	16,16,                                  /* 16x16 tiles */
	0x100000/32,                            /* number of tiles */
	4,                                      /* 4 bpp */
	{ 3*0x100000*8, 2*0x100000*8, 1*0x100000*8, 0*0x100000*8 },
	{
		0, 1, 2, 3, 4, 5, 6, 7,
		16*8+0, 16*8+1, 16*8+2, 16*8+3, 16*8+4, 16*8+5, 16*8+6, 16*8+7
	},
	{
		0*8, 1*8, 2*8, 3*8, 4*8, 5*8, 6*8, 7*8,
		8*8, 9*8, 10*8, 11*8, 12*8, 13*8, 14*8, 15*8
	},
	32*8
};

static GFXDECODE_START( glass )
	GFXDECODE_ENTRY( "gfx1", 0x000000, glass_tilelayout16, 0, 64 )
GFXDECODE_END


WRITE16_MEMBER(glass_state::OKIM6295_bankswitch_w)
{
	if (ACCESSING_BITS_0_7)
		membank("okibank")->set_entry(data & 0x0f);
}

WRITE16_MEMBER(glass_state::coin_w)
{
	switch (offset >> 3)
	{
		case 0x00:  /* Coin Lockouts */
		case 0x01:
			machine().bookkeeping().coin_lockout_w((offset >> 3) & 0x01, ~data & 0x01);
			break;
		case 0x02:  /* Coin Counters */
		case 0x03:
			machine().bookkeeping().coin_counter_w((offset >> 3) & 0x01, data & 0x01);
			break;
		case 0x04:  /* Sound Muting (if bit 0 == 1, sound output stream = 0) */
			break;
	}
}

static ADDRESS_MAP_START( glass_map, AS_PROGRAM, 16, glass_state )
	AM_RANGE(0x000000, 0x0fffff) AM_ROM                                                                     /* ROM */
	AM_RANGE(0x100000, 0x101fff) AM_RAM_WRITE(vram_w) AM_SHARE("videoram")                            /* Video RAM */
	AM_RANGE(0x102000, 0x102fff) AM_RAM                                                                     /* Extra Video RAM */
	AM_RANGE(0x108000, 0x108007) AM_WRITEONLY AM_SHARE("vregs")                                             /* Video Registers */
	AM_RANGE(0x108008, 0x108009) AM_WRITE(clr_int_w)                                                        /* CLR INT Video */
	AM_RANGE(0x200000, 0x2007ff) AM_RAM_DEVWRITE("palette", palette_device, write) AM_SHARE("palette")    /* Palette */
	AM_RANGE(0x440000, 0x440fff) AM_RAM AM_SHARE("spriteram")                                               /* Sprite RAM */
	AM_RANGE(0x700000, 0x700001) AM_READ_PORT("DSW2")
	AM_RANGE(0x700002, 0x700003) AM_READ_PORT("DSW1")
	AM_RANGE(0x700004, 0x700005) AM_READ_PORT("P1")
	AM_RANGE(0x700006, 0x700007) AM_READ_PORT("P2")
	AM_RANGE(0x700008, 0x700009) AM_WRITE(blitter_w)                                                  /* serial blitter */
	AM_RANGE(0x70000c, 0x70000d) AM_WRITE(OKIM6295_bankswitch_w)                                            /* OKI6295 bankswitch */
	AM_RANGE(0x70000e, 0x70000f) AM_DEVREADWRITE8("oki", okim6295_device, read, write, 0x00ff)              /* OKI6295 status register */
	AM_RANGE(0x70000a, 0x70004b) AM_WRITE(coin_w)                                                     /* Coin Counters/Lockout */
	AM_RANGE(0xfec000, 0xfeffff) AM_RAM AM_SHARE("mainram")                                                 /* Work RAM (partially shared with DS5002FP) */
ADDRESS_MAP_END


static ADDRESS_MAP_START( oki_map, AS_0, 8, glass_state )
	AM_RANGE(0x00000, 0x2ffff) AM_ROM
	AM_RANGE(0x30000, 0x3ffff) AM_ROMBANK("okibank")
ADDRESS_MAP_END


static INPUT_PORTS_START( glass )
	PORT_START("DSW1")
	PORT_DIPNAME( 0x07, 0x07, DEF_STR( Coin_A ) ) PORT_DIPLOCATION("SW1:6,7,8")
	PORT_DIPSETTING(    0x07, DEF_STR( 1C_1C ) )
	PORT_DIPSETTING(    0x00, DEF_STR( 3C_4C ) )
	PORT_DIPSETTING(    0x01, DEF_STR( 2C_3C ) )
	PORT_DIPSETTING(    0x06, DEF_STR( 1C_2C ) )
	PORT_DIPSETTING(    0x05, DEF_STR( 1C_3C ) )
	PORT_DIPSETTING(    0x04, DEF_STR( 1C_4C ) )
	PORT_DIPSETTING(    0x03, DEF_STR( 1C_5C ) )
	PORT_DIPSETTING(    0x02, DEF_STR( 1C_6C ) )
	PORT_DIPNAME( 0x38, 0x38, DEF_STR( Coin_B ) ) PORT_DIPLOCATION("SW1:3,4,5")
	PORT_DIPSETTING(    0x10, DEF_STR( 6C_1C ) )
	PORT_DIPSETTING(    0x18, DEF_STR( 5C_1C ) )
	PORT_DIPSETTING(    0x20, DEF_STR( 4C_1C ) )
	PORT_DIPSETTING(    0x28, DEF_STR( 3C_1C ) )
	PORT_DIPSETTING(    0x30, DEF_STR( 2C_1C ) )
	PORT_DIPSETTING(    0x08, DEF_STR( 3C_2C ) )
	PORT_DIPSETTING(    0x00, DEF_STR( 4C_3C ) )
	PORT_DIPSETTING(    0x38, DEF_STR( 1C_1C ) )
	PORT_DIPNAME( 0x40, 0x40, "Credit configuration" ) PORT_DIPLOCATION("SW1:2")
	PORT_DIPSETTING(    0x40, "Start 1C" )
	PORT_DIPSETTING(    0x00, "Start 2C" )
	PORT_DIPNAME( 0x80, 0x80, DEF_STR( Free_Play ) ) PORT_DIPLOCATION("SW1:1")
	PORT_DIPSETTING(    0x80, DEF_STR( Off ) )
	PORT_DIPSETTING(    0x00, DEF_STR( On ) )

	PORT_START("DSW2")
	PORT_DIPNAME( 0x03, 0x03, DEF_STR( Difficulty ) ) PORT_DIPLOCATION("SW2:7,8")
	PORT_DIPSETTING(    0x02, DEF_STR( Easy ) )
	PORT_DIPSETTING(    0x03, DEF_STR( Normal ) )
	PORT_DIPSETTING(    0x01, DEF_STR( Hard ) )
	PORT_DIPSETTING(    0x00, DEF_STR( Hardest ) )
	PORT_DIPNAME( 0x0c, 0x0c, DEF_STR( Lives ) ) PORT_DIPLOCATION("SW2:5,6")
	PORT_DIPSETTING(    0x0c, "3" )
	PORT_DIPSETTING(    0x08, "1" )
	PORT_DIPSETTING(    0x04, "2" )
	PORT_DIPSETTING(    0x00, "4" )
	PORT_DIPNAME( 0x10, 0x10, DEF_STR( Version ) ) PORT_DIPLOCATION("SW2:4")
	PORT_DIPSETTING(    0x10, DEF_STR( Normal ) )
	PORT_DIPSETTING(    0x00, "Light" )
	PORT_DIPNAME( 0x20, 0x20, DEF_STR( Demo_Sounds ) ) PORT_DIPLOCATION("SW2:3")
	PORT_DIPSETTING(    0x00, DEF_STR( Off ) )
	PORT_DIPSETTING(    0x20, DEF_STR( On ) )
	PORT_DIPUNUSED_DIPLOC( 0x40, 0x40, "SW2:2" ) /* Listed as "Unused" */
	PORT_SERVICE_DIPLOC( 0x80, IP_ACTIVE_LOW, "SW2:1" )

	PORT_START("P1")
	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_JOYSTICK_UP ) PORT_8WAY PORT_PLAYER(1)
	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN ) PORT_8WAY PORT_PLAYER(1)
	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_8WAY PORT_PLAYER(1)
	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT ) 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_COIN1 )
	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_COIN2 )

	PORT_START("P2")
	PORT_BIT( 0x0001, IP_ACTIVE_LOW, IPT_JOYSTICK_UP ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x0002, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x0004, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x0008, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT ) PORT_8WAY PORT_PLAYER(2)
	PORT_BIT( 0x0010, IP_ACTIVE_LOW, IPT_BUTTON2 ) PORT_PLAYER(2)
	PORT_BIT( 0x0020, IP_ACTIVE_LOW, IPT_BUTTON1 ) PORT_PLAYER(2)
	PORT_BIT( 0x0040, IP_ACTIVE_LOW, IPT_START1 )
	PORT_BIT( 0x0080, IP_ACTIVE_LOW, IPT_START2 )
	PORT_BIT( 0x0100, IP_ACTIVE_LOW, IPT_BUTTON3 ) PORT_PLAYER(1)
	PORT_BIT( 0x0200, IP_ACTIVE_LOW, IPT_BUTTON3 ) PORT_PLAYER(2)
	PORT_BIT( 0xfc00, IP_ACTIVE_LOW, IPT_UNKNOWN )
INPUT_PORTS_END



void glass_state::machine_start()
{
	membank("okibank")->configure_entries(0, 16, memregion("oki")->base(), 0x10000);

	save_item(NAME(m_cause_interrupt));
	save_item(NAME(m_current_bit));
	save_item(NAME(m_current_command));
	save_item(NAME(m_blitter_serial_buffer));
}

void glass_state::machine_reset()
{
	m_cause_interrupt = 1;
	m_current_bit = 0;
	m_current_command = 0;

	for (int i = 0; i < 5; i++)
		m_blitter_serial_buffer[i] = 0;
}

static MACHINE_CONFIG_START( glass, glass_state )

	/* basic machine hardware */
	MCFG_CPU_ADD("maincpu", M68000, XTAL_24MHz/2)      /* 12 MHz verified on PCB */
	MCFG_CPU_PROGRAM_MAP(glass_map)
	MCFG_CPU_VBLANK_INT_DRIVER("screen", glass_state,  interrupt)


	/* video hardware */
	MCFG_SCREEN_ADD("screen", RASTER)
	MCFG_SCREEN_REFRESH_RATE(60)
	MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(2500) /* not accurate */)
	MCFG_SCREEN_SIZE(32*16, 32*16)
	MCFG_SCREEN_VISIBLE_AREA(0, 368-1, 16, 256-1)
	MCFG_SCREEN_UPDATE_DRIVER(glass_state, screen_update)
	MCFG_SCREEN_PALETTE("palette")

	MCFG_GFXDECODE_ADD("gfxdecode", "palette", glass)
	MCFG_PALETTE_ADD("palette", 1024)
	MCFG_PALETTE_FORMAT(xBBBBBGGGGGRRRRR)

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

	MCFG_OKIM6295_ADD("oki", XTAL_1MHz, OKIM6295_PIN7_HIGH) /* 1MHz Resonator & pin 7 high verified on PCB */
	MCFG_DEVICE_ADDRESS_MAP(AS_0, oki_map)
	MCFG_SOUND_ROUTE(ALL_OUTPUTS, "mono", 1.0)
MACHINE_CONFIG_END

ROM_START( glass ) /* Version 1.1 */
	ROM_REGION( 0x100000, "maincpu", 0 )    /* 68000 code */
	ROM_LOAD16_BYTE( "1.c23", 0x000000, 0x040000, CRC(aeebd4ed) SHA1(04759dc146dff0fc74b78d70e79dfaebe68328f9) )
	ROM_LOAD16_BYTE( "2.c22", 0x000001, 0x040000, CRC(165e2e01) SHA1(180a2e2b5151f2321d85ac23eff7fbc9f52023a5) )

	ROM_REGION( 0x10000, "mcu", 0 ) /* DS5002FP code */
	ROM_LOAD( "glass_ds5002fp.bin", 0x00000, 0x8000, NO_DUMP )

	ROM_REGION( 0x400000, "gfx1", ROMREGION_ERASE00 )   /* Graphics */
	/* 0x000000-0x3fffff filled in later in the DRIVER_INIT */

	ROM_REGION( 0x400000, "gfx2", 0 )   /* Graphics */
	ROM_LOAD( "h13.bin", 0x000000, 0x200000, CRC(13ab7f31) SHA1(468424f74d6cccd1b445a9f20e2d24bc46d61ed6) )
	ROM_LOAD( "h11.bin", 0x200000, 0x200000, CRC(c6ac41c8) SHA1(22408ef1e35c66d0fba0c72972c46fad891d1193) )

	ROM_REGION( 0x100000, "gfx3", 0 )   /* 16 bitmaps (320x200, indexed colors) */
	ROM_LOAD( "h9.bin", 0x000000, 0x100000, CRC(b9492557) SHA1(3f5c0d696d65e1cd492763dfa749c813dd56a9bf) )

	ROM_REGION( 0x100000, "oki", 0 )    /* ADPCM samples - sound chip is OKIM6295 */
	ROM_LOAD( "c1.bin", 0x000000, 0x100000, CRC(d9f075a2) SHA1(31a7a677861f39d512e9d1f51925c689e481159a) )
	/* 0x00000-0x2ffff is fixed, 0x30000-0x3ffff is bank switched from all the ROMs */
ROM_END

ROM_START( glass10 ) /* Version 1.0 */
	ROM_REGION( 0x100000, "maincpu", 0 )    /* 68000 code */
	ROM_LOAD16_BYTE( "c23.bin", 0x000000, 0x040000, CRC(688cdf33) SHA1(b59dcc3fc15f72037692b745927b110e97d8282e) )
	ROM_LOAD16_BYTE( "c22.bin", 0x000001, 0x040000, CRC(ab17c992) SHA1(1509b5b4bbfb4e022e0ab6fbbc0ffc070adfa531) )

	ROM_REGION( 0x10000, "mcu", 0 ) /* DS5002FP code */
	ROM_LOAD( "glass_ds5002fp.bin", 0x00000, 0x8000, NO_DUMP )

	ROM_REGION( 0x400000, "gfx1", ROMREGION_ERASE00 )   /* Graphics */
	/* 0x000000-0x3fffff filled in later in the DRIVER_INIT */

	ROM_REGION( 0x400000, "gfx2", 0 )   /* Graphics */
	ROM_LOAD( "h13.bin", 0x000000, 0x200000, CRC(13ab7f31) SHA1(468424f74d6cccd1b445a9f20e2d24bc46d61ed6) )
	ROM_LOAD( "h11.bin", 0x200000, 0x200000, CRC(c6ac41c8) SHA1(22408ef1e35c66d0fba0c72972c46fad891d1193) )

	ROM_REGION( 0x100000, "gfx3", 0 )   /* 16 bitmaps (320x200, indexed colors) */
	ROM_LOAD( "h9.bin", 0x000000, 0x100000, CRC(b9492557) SHA1(3f5c0d696d65e1cd492763dfa749c813dd56a9bf) )

	ROM_REGION( 0x100000, "oki", 0 )    /* ADPCM samples - sound chip is OKIM6295 */
	ROM_LOAD( "c1.bin", 0x000000, 0x100000, CRC(d9f075a2) SHA1(31a7a677861f39d512e9d1f51925c689e481159a) )
	/* 0x00000-0x2ffff is fixed, 0x30000-0x3ffff is bank switched from all the ROMs */
ROM_END

ROM_START( glass10a ) /* Title screen shows "GLASS" and under that "Break Edition" on a real PCB */
	ROM_REGION( 0x100000, "maincpu", 0 )    /* 68000 code */
	ROM_LOAD16_BYTE( "spl-c23.bin", 0x000000, 0x040000, CRC(c1393bea) SHA1(a5f877ba38305a7b49fa3c96b9344cbf71e8c9ef) )
	ROM_LOAD16_BYTE( "spl-c22.bin", 0x000001, 0x040000, CRC(0d6fa33e) SHA1(37e9258ef7e108d034c80abc8e5e5ab6dacf0a61) )

	ROM_REGION( 0x10000, "mcu", 0 ) /* DS5002FP code */
	ROM_LOAD( "glass_ds5002fp.bin", 0x00000, 0x8000, NO_DUMP )

	ROM_REGION( 0x400000, "gfx1", ROMREGION_ERASE00 )   /* Graphics */
	/* 0x000000-0x3fffff filled in later in the DRIVER_INIT */

	ROM_REGION( 0x400000, "gfx2", 0 )   /* Graphics */
	ROM_LOAD( "h13.bin", 0x000000, 0x200000, CRC(13ab7f31) SHA1(468424f74d6cccd1b445a9f20e2d24bc46d61ed6) )
	ROM_LOAD( "h11.bin", 0x200000, 0x200000, CRC(c6ac41c8) SHA1(22408ef1e35c66d0fba0c72972c46fad891d1193) )

	ROM_REGION( 0x100000, "gfx3", 0 )   /* 16 bitmaps (320x200, indexed colors) */
	ROM_LOAD( "h9.bin", 0x000000, 0x100000, CRC(b9492557) SHA1(3f5c0d696d65e1cd492763dfa749c813dd56a9bf) )

	ROM_REGION( 0x100000, "oki", 0 )    /* ADPCM samples - sound chip is OKIM6295 */
	ROM_LOAD( "c1.bin", 0x000000, 0x100000, CRC(d9f075a2) SHA1(31a7a677861f39d512e9d1f51925c689e481159a) )
	/* 0x00000-0x2ffff is fixed, 0x30000-0x3ffff is bank switched from all the ROMs */
ROM_END

ROM_START( glasskr )
	ROM_REGION( 0x100000, "maincpu", 0 )    /* 68000 code */
	ROM_LOAD16_BYTE( "glassk.c23", 0x000000, 0x080000, CRC(6ee19376) SHA1(8a8fdeebe094bd3e29c35cf59584e3cab708732d) )
	ROM_LOAD16_BYTE( "glassk.c22", 0x000001, 0x080000, CRC(bd546568) SHA1(bcd5e7591f4e68c9470999b8a0ef1ee4392c907c) )

	ROM_REGION( 0x400000, "gfx1", ROMREGION_ERASE00 )   /* Graphics */
	/* 0x000000-0x3fffff filled in later in the DRIVER_INIT */

	ROM_REGION( 0x400000, "gfx2", 0 )   /* Graphics */
	ROM_LOAD( "h13.bin", 0x000000, 0x200000, CRC(13ab7f31) SHA1(468424f74d6cccd1b445a9f20e2d24bc46d61ed6) )
	ROM_LOAD( "h11.bin", 0x200000, 0x200000, CRC(c6ac41c8) SHA1(22408ef1e35c66d0fba0c72972c46fad891d1193) )

	ROM_REGION( 0x100000, "gfx3", 0 )   /* 16 bitmaps (320x200, indexed colors) */
	ROM_LOAD( "glassk.h9", 0x000000, 0x100000, CRC(d499be4c) SHA1(204f754813be687e8dc00bfe7b5dbc4857ac8738) )

	ROM_REGION( 0x100000, "oki", 0 )    /* ADPCM samples - sound chip is OKIM6295 */
	ROM_LOAD( "c1.bin", 0x000000, 0x100000, CRC(d9f075a2) SHA1(31a7a677861f39d512e9d1f51925c689e481159a) )
	/* 0x00000-0x2ffff is fixed, 0x30000-0x3ffff is bank switched from all the ROMs */
ROM_END

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

    Split even/odd bytes from ROMs in 16 bit mode to different memory areas

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

void glass_state::ROM16_split_gfx( const char *src_reg, const char *dst_reg, int start, int length, int dest1, int dest2 )
{
	int i;

	/* get a pointer to the source data */
	UINT8 *src = (UINT8 *)memregion(src_reg)->base();

	/* get a pointer to the destination data */
	UINT8 *dst = (UINT8 *)memregion(dst_reg)->base();

	/* fill destination areas with the proper data */
	for (i = 0; i < length / 2; i++)
	{
		dst[dest1 + i] = src[start + i * 2 + 0];
		dst[dest2 + i] = src[start + i * 2 + 1];
	}
}

/* How does the protection work?

  We know in World Rally it shares the whole of main RAM with the Dallas, with subtle reads and writes / values being checked.. so I guess this will be similar at least
  and thus very hard to figure out if done properly

 */

READ16_MEMBER( glass_state::mainram_r )
{
	UINT16 ret = m_mainram[offset];
	int pc = space.device().safe_pc();

	if (offset == (0xfede96 - 0xfec000)>>1)
	{
		// this address seems important, the game will abort with 'power failure' depending on some reads, presumably referring to the power to the battery

		// there are also various code segments like the one below
		/*
		start:
		tst.b   this address
		bne     end
		tst.b   $fede1d.l
		nop << why?
		bne     start
		end:
		*/
		return 0x0000;
		//printf("%06x read %06x - %04x %04x\n", pc , (offset*2 + 0xfec000), ret, mem_mask);
	}
	else if (offset == (0xfede1c - 0xfec000)>>1)
	{
		// related to above, could also be some command ack?
		logerror("%06x read %06x - %04x %04x\n",  pc, (offset*2 + 0xfec000), ret, mem_mask);
	}
	else if (offset == (0xfede26 - 0xfec000)>>1)
	{
		logerror("%06x read %06x - %04x %04x\n",  pc, (offset*2 + 0xfec000), ret, mem_mask);
	}
	return ret;
}

WRITE16_MEMBER( glass_state::mainram_w )
{
	int pc = space.device().safe_pc();

	COMBINE_DATA(&m_mainram[offset]);

	if (offset == (0xfede02 - 0xfec000)>>1)
	{
//      printf("%06x write %06x - %04x %04x\n",  pc, (offset*2 + 0xfec000), data, mem_mask);
		// several checks write here then expect it to appear mirrored, might be some kind of command + command ack
		if (mem_mask & 0xff00) // sometimes mask 0xff00, but not in cases which poll for change
		{
			mem_mask = 0x00ff;
			data >>=8;
			COMBINE_DATA(&m_mainram[offset]);
		}
		return;
	}
	else if (offset == (0xfede1c - 0xfec000)>>1)
	{
		// see notes about 0xfede96 in read, this address seems important
		logerror("%06x write %06x - %04x %04x\n",  pc, (offset*2 + 0xfec000), data, mem_mask);
		if (mem_mask == 0x00ff)
		{
			int realdata = data;

			// don't store the bits written, game checks they get cleared?
			data &= 0xff00;
			COMBINE_DATA(&m_mainram[offset]);

			// a command?
			if (realdata == 0x0002)
			{
				// there is a check on address 0xfede26 just after writing 0002 here..
				offset = (0xfede26 - 0xfec000) >> 1;
				data = 0xff00;
				mem_mask = 0xff00;
				COMBINE_DATA(&m_mainram[offset]);
			}
		}
		return;
	}

}

DRIVER_INIT_MEMBER(glass_state, glass)
{
	/*
	For "gfx2" we have this memory map:
	    0x000000-0x1fffff ROM H13
	    0x200000-0x3fffff ROM H11

	and we are going to construct this one for "gfx1":
	    0x000000-0x0fffff ROM H13 even bytes
	    0x100000-0x1fffff ROM H13 odd bytes
	    0x200000-0x2fffff ROM H11 even bytes
	    0x300000-0x3fffff ROM H11 odd bytes
	*/

	/* split ROM H13 */
	ROM16_split_gfx("gfx2", "gfx1", 0x0000000, 0x0200000, 0x0000000, 0x0100000);

	/* split ROM H11 */
	ROM16_split_gfx("gfx2", "gfx1", 0x0200000, 0x0200000, 0x0200000, 0x0300000);

}


DRIVER_INIT_MEMBER(glass_state,glassp)
{
	DRIVER_INIT_CALL(glass);

	/* install custom handler over RAM for protection */
	m_maincpu->space(AS_PROGRAM).install_readwrite_handler(0xfec000, 0xfeffff, read16_delegate(FUNC(glass_state::mainram_r), this), write16_delegate(FUNC(glass_state::mainram_w),this));

}

// ALL versions of Glass contain the 'Break Edition' string (it just seems to be part of the title?)
// The 2 version 1.0 releases are very similar code, it was thought that one was a break edition and the other wasn't, but as both contain the string this seems unlikely.
// Version 1.1 releases also show Version 1994 on the title screen.  These versions do not have skulls in the playfield (at least not on early stages)
// The unprotected version appears to be a Korean set, is censored, and has different girl pictures.

GAME( 1994, glass,    0,     glass, glass, glass_state, glassp, ROT0, "OMK / Gaelco",                  "Glass (Ver 1.1, Break Edition, Version 1994)",                           MACHINE_UNEMULATED_PROTECTION | MACHINE_NOT_WORKING | MACHINE_SUPPORTS_SAVE )
GAME( 1994, glasskr,  glass, glass, glass, glass_state, glass,  ROT0, "OMK / Gaelco (Promat license)", "Glass (Ver 1.1, Break Edition, Version 1994) (censored, unprotected)",   MACHINE_SUPPORTS_SAVE ) // promat stickers on program roms
GAME( 1993, glass10,  glass, glass, glass, glass_state, glassp, ROT0, "OMK / Gaelco",                  "Glass (Ver 1.0, Break Edition) (set 1)",                                 MACHINE_UNEMULATED_PROTECTION | MACHINE_NOT_WORKING | MACHINE_SUPPORTS_SAVE )
GAME( 1993, glass10a, glass, glass, glass, glass_state, glassp, ROT0, "OMK / Gaelco",                  "Glass (Ver 1.0, Break Edition) (set 2)",                                 MACHINE_UNEMULATED_PROTECTION | MACHINE_NOT_WORKING | MACHINE_SUPPORTS_SAVE )
