- Driver clean-up, including driver state

- Tried improving on the ROM mirroring, without any success.  Maybe somebody could look into it -- right now it requires all kinds of trickery and even a memcpy ;)  All I know is that everything that's there right now is needed otherwise either the game fails the ROM test, or Galaga crashes

.gitattributes

@@ -2093,6 +2093,7 @@ src/mame/drivers/zodiack.c svneol=native#text/plain
 src/mame/drivers/zr107.c svneol=native#text/plain
 src/mame/etc/fd1094dp.c svneol=native#text/plain
 src/mame/etc/jrcrypt.c svneol=native#text/plain
+src/mame/includes/20pacgal.h svneol=native#text/plain
 src/mame/includes/8080bw.h svneol=native#text/plain
 src/mame/includes/amiga.h svneol=native#text/plain
 src/mame/includes/appoooh.h svneol=native#text/plain

src/mame/drivers/20pacgal.c

@@ -1,18 +1,16 @@
 /***************************************************************************
 
-Ms.Pac-Man/Galaga - 20 Year Reunion
+    Ms.Pac-Man/Galaga - 20 Year Reunion hardware
 
-driver by Nicola Salmoria
+    driver by Nicola Salmoria
 
-Notes:
+    Notes:
-- There are four start buttons: the first two are for Ms. Pac-Man, the other two
+        * There are four start buttons: the first two are for Ms. Pac-Man, the other two
           for Galaga.
-
+        * To play Pac-Man instead of Ms. Pac-Man, insert coins then enter the following
-- To play Pac-Man instead of Ms. Pac-Man, insert coins then enter the following
           sequence: U U U D D D L R L R L. A sound will play and the ghost will change
           from red to pink.
-
+        * Writes to the Z180 ASCI port:
-- Writes to the Z180 ASCI port:
           MS PAC-MAN/GALAGA
           arcade video system
           version 1.01
@@ -20,18 +18,15 @@ Notes:
           >
           and it listens for incoming characters.
 
-
+    Known issues/to-do's:
-TODO:
+        * Crashed on reset - Z180 core problem?
-- Starfield.
+        * ROM banking is not understood.  Shouldn't require copying and other
-
+          trickey
-- Convert to tilemaps & optimize video rendering, I was just too lazy to do it for now.
+        * Starfield missing
-
+        * Check the ASCI interface, there probably is fully working debug code.
-- Check the ASCI interface, there probably is fully working debug code.
+        * The timed interrupt is a kludge; it is supposed to be generated internally by
-
-- The timed interrupt is a kludge; it is supposed to be generated internally by
           the Z180, but the cpu core doesn't support that yet.
-
+        * Correct CPU speed... Zilog says Z180 comes in 6, 8, 10, 20 & 33MHz.
-- Correct CPU speed... Zilog says Z180 comes in 6, 8, 10, 20 & 33MHz.
           20MHz is used as it "seems" right based on the music in Galaga
 
 ***************************************************************************/
@@ -39,24 +34,56 @@ TODO:
 #include "driver.h"
 #include "deprecat.h"
 #include "machine/eeprom.h"
-#include "cpu/z180/z180.h"
-#include "pacman.h"
 #include "sound/namco.h"
 #include "sound/dac.h"
-
+#include "20pacgal.h"
-extern UINT8 *pacgal_charram,*pacgal_sprram;
-extern UINT8 *pacgal_videoram,*pacgal_videoram2;
-PALETTE_INIT( 20pacgal );
-VIDEO_START( 20pacgal );
-WRITE8_HANDLER( pacgal_lookup_w );
-WRITE8_HANDLER( pacgal_active_game_w );
-WRITE8_HANDLER( pacgal_videoram2_w );
-WRITE8_HANDLER( pacgal_charram_w );
-WRITE8_HANDLER( pacgal_sprram_w );
-VIDEO_UPDATE( 20pacgal );
 
 
 
+/*************************************
+ *
+ *  Interrupt system
+ *
+ *************************************/
+
+static WRITE8_HANDLER( irqack_w )
+{
+	int bit = data & 1;
+
+	cpu_interrupt_enable(0, bit);
+
+	if (!bit)
+		cpunum_set_input_line(Machine, 0, 0, CLEAR_LINE );
+}
+
+
+
+/*************************************
+ *
+ *  Audio
+ *
+ *************************************/
+
+static const struct namco_interface namco_interface =
+{
+	3,	/* number of voices */
+	-1,	/* memory region */
+};
+
+
+static WRITE8_HANDLER( _20pacgal_dac_w )
+{
+	DAC_signed_data_w(0, data);
+}
+
+
+
+/*************************************
+ *
+ *  Non-volatile memory
+ *
+ *************************************/
+
 static const struct EEPROM_interface eeprom_interface =
 {
 	7,				/* address bits */
@@ -68,6 +95,7 @@ static const struct EEPROM_interface eeprom_interface =
 	"*10011xxxxx",	/* unlock command */
 };
 
+
 static NVRAM_HANDLER( eeprom )
 {
 	if (read_or_write)
@@ -81,15 +109,14 @@ static NVRAM_HANDLER( eeprom )
 	}
 }
 
+
 static READ8_HANDLER( eeprom_r )
 {
-	int res;
-
 	/* bit 7 is EEPROM data */
-	res = EEPROM_read_bit() << 7;
+	return EEPROM_read_bit() << 7;
-	return res;
 }
 
+
 static WRITE8_HANDLER( eeprom_w )
 {
 	/* bit 7 is data */
@@ -100,50 +127,85 @@ static WRITE8_HANDLER( eeprom_w )
 	EEPROM_set_clock_line((data & 0x40) ? ASSERT_LINE : CLEAR_LINE);
 }
 
-static WRITE8_HANDLER( irqack_w )
-{
-	int bit = data & 1;
-	cpu_interrupt_enable(0,bit);
-	if (!bit)
-		cpunum_set_input_line(Machine, 0, 0, CLEAR_LINE );
-}
 
-static WRITE8_HANDLER( flipscreen_w )
-{
-	flip_screen_set(data & 1);
-}
 
-static WRITE8_HANDLER( pacgal_dac_w )
+/*************************************
-{
+ *
-	DAC_signed_data_w(0, data);
+ *  Coin counter
-}
+ *
+ *************************************/
 
-static WRITE8_HANDLER( coin_w )
+static WRITE8_HANDLER( _20pacgal_coin_counter_w )
 {
-	coin_counter_w(0,data & 1);
+	coin_counter_w(0, data & 1);
 }
 
 
 
+/*************************************
+ *
+ *  ROM banking - FIXME
+ *
+ *************************************/
+
+WRITE8_HANDLER( rom_bank_select_w )
+{
+	_20pacgal_state *state = Machine->driver_data;
+
+	state->game_selected = data & 1;
+
+	if (state->game_selected == 0)
+		memcpy(memory_region(REGION_CPU1)+0x48000, memory_region(REGION_CPU1)+0x8000, 0x2000);
+}
+
+
+WRITE8_HANDLER( rom_48000_w )
+{
+	_20pacgal_state *state = Machine->driver_data;
+
+	if (state->game_selected)
+	{
+		if (offset < 0x0800)
+			state->video_ram[offset & 0x07ff] = data;
+
+		memory_region(REGION_CPU1)[0x48000 + offset] = data;
+	}
+}
+
+
+
+/*************************************
+ *
+ *  Memory handlers
+ *
+ *************************************/
+
 static ADDRESS_MAP_START( 20pacgal_map, ADDRESS_SPACE_PROGRAM, 8 )
 	AM_RANGE(0x00000, 0x03fff) AM_ROM
 	AM_RANGE(0x08000, 0x09fff) AM_ROM
 	AM_RANGE(0x0a000, 0x0ffff) AM_MIRROR(0x40000) AM_ROM
 	AM_RANGE(0x10000, 0x3ffff) AM_ROM
-	AM_RANGE(0x44000, 0x447ff) AM_RAM AM_BASE(&pacgal_videoram)						// mspacman tilemap
+	AM_RANGE(0x44000, 0x447ff) AM_RAM AM_BASE_MEMBER(_20pacgal_state, video_ram)
 	AM_RANGE(0x45040, 0x4505f) AM_WRITE(pacman_sound_w) AM_BASE(&namco_soundregs)
 	AM_RANGE(0x44800, 0x45eff) AM_RAM
-	AM_RANGE(0x45f00, 0x45fff) AM_WRITE(_20pacgal_wavedata_w) AM_BASE(&namco_wavedata) // sound wave data
+	AM_RANGE(0x45f00, 0x45fff) AM_WRITE(_20pacgal_wavedata_w) AM_BASE(&namco_wavedata)
-	AM_RANGE(0x46000, 0x46fff) AM_WRITE(pacgal_charram_w) AM_BASE(&pacgal_charram)	// char gfx data
+	AM_RANGE(0x46000, 0x46fff) AM_WRITE(MWA8_RAM) AM_BASE_MEMBER(_20pacgal_state, char_gfx_ram)
-	AM_RANGE(0x47100, 0x47100) AM_RAM						// leftover from original Galaga code
+	AM_RANGE(0x47100, 0x47100) AM_RAM	/* leftover from original Galaga code */
-	AM_RANGE(0x48000, 0x49fff) AM_ROM AM_BASE(&pacgal_videoram2)
+	AM_RANGE(0x48000, 0x49fff) AM_READWRITE(MRA8_ROM, rom_48000_w)	/* this should be a mirror of 08000-09ffff */
-	AM_RANGE(0x48000, 0x49fff) AM_WRITE(pacgal_videoram2_w)							// ROM or galaga tilemap (banked)
+	AM_RANGE(0x4c000, 0x4dfff) AM_WRITE(MWA8_RAM) AM_BASE_MEMBER(_20pacgal_state, sprite_gfx_ram)
-	AM_RANGE(0x4c000, 0x4dfff) AM_WRITE(pacgal_sprram_w) AM_BASE(&pacgal_sprram)	// sprite gfx data
+	AM_RANGE(0x4e000, 0x4e17f) AM_WRITE(MWA8_RAM) AM_BASE_MEMBER(_20pacgal_state, sprite_ram)
-	AM_RANGE(0x4e000, 0x4e17f) AM_WRITE(MWA8_RAM) AM_BASE(&spriteram)				// sprite registers
+	AM_RANGE(0x4ff00, 0x4ffff) AM_WRITE(MWA8_RAM) AM_BASE_MEMBER(_20pacgal_state, sprite_color_lookup)
-	AM_RANGE(0x4ff00, 0x4ffff) AM_WRITE(pacgal_lookup_w)							// sprite color lookup table
 ADDRESS_MAP_END
 
-static ADDRESS_MAP_START( 20pacgal_port, ADDRESS_SPACE_IO, 8 )
+
+
+/*************************************
+ *
+ *  I/O port handlers
+ *
+ *************************************/
+
+static ADDRESS_MAP_START( 20pacgal_io_map, ADDRESS_SPACE_IO, 8 )
 	ADDRESS_MAP_FLAGS( AMEF_ABITS(8) )
 	AM_RANGE(0x00, 0x3f) AM_NOP /* Z180 internal registers */
 	AM_RANGE(0x40, 0x7f) AM_NOP	/* Z180 internal registers */
@@ -151,19 +213,25 @@ static ADDRESS_MAP_START( 20pacgal_port, ADDRESS_SPACE_IO, 8 )
 	AM_RANGE(0x81, 0x81) AM_READ(input_port_1_r)
 	AM_RANGE(0x82, 0x82) AM_READ(input_port_2_r)
 	AM_RANGE(0x80, 0x80) AM_WRITE(watchdog_reset_w)
-	AM_RANGE(0x81, 0x81) AM_WRITE(MWA8_NOP)				// ??? pulsed by the timer irq
+	AM_RANGE(0x81, 0x81) AM_WRITE(MWA8_NOP)				/* ??? pulsed by the timer irq */
 	AM_RANGE(0x82, 0x82) AM_WRITE(irqack_w)
-	AM_RANGE(0x85, 0x86) AM_WRITE(MWA8_NOP)				// stars: rng seed (lo/hi)
+	AM_RANGE(0x85, 0x86) AM_WRITE(MWA8_NOP)				/* stars: rng seed (lo/hi) */
 	AM_RANGE(0x87, 0x87) AM_READWRITE(eeprom_r, eeprom_w)
-	AM_RANGE(0x88, 0x88) AM_WRITE(pacgal_active_game_w)
+	AM_RANGE(0x88, 0x88) AM_WRITE(rom_bank_select_w)
-	AM_RANGE(0x89, 0x89) AM_WRITE(pacgal_dac_w)
+	AM_RANGE(0x89, 0x89) AM_WRITE(_20pacgal_dac_w)
-	AM_RANGE(0x8a, 0x8a) AM_WRITE(MWA8_NOP)				// stars: bits 3-4 = active set; bit 5 = enable
+	AM_RANGE(0x8a, 0x8a) AM_WRITE(MWA8_NOP)				/* stars: bits 3-4 = active set; bit 5 = enable */
-	AM_RANGE(0x8b, 0x8b) AM_WRITE(flipscreen_w)
+	AM_RANGE(0x8b, 0x8b) AM_WRITE(MWA8_RAM) AM_BASE_MEMBER(_20pacgal_state, flip_screen)
-	AM_RANGE(0x8f, 0x8f) AM_WRITE(coin_w)				// coin counter
+	AM_RANGE(0x8f, 0x8f) AM_WRITE(_20pacgal_coin_counter_w)
 ADDRESS_MAP_END
 
 
 
+/*************************************
+ *
+ *  Port definitions
+ *
+ *************************************/
+
 static INPUT_PORTS_START( 20pacgal )
 	PORT_START
 	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_JOYSTICK_UP    )
@@ -180,10 +248,10 @@ static INPUT_PORTS_START( 20pacgal )
 	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT  ) PORT_COCKTAIL
 	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT ) PORT_COCKTAIL
 	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN  ) PORT_COCKTAIL
-	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_START3 )
+	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_START3 ) PORT_NAME( "Right 1 Player Start" )
-	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_START1 )
+	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_START1 ) PORT_NAME( "Left 1 Player Start" )
-	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_START2 )
+	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_START2 ) PORT_NAME( "Left 2 Players Start" )
-	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_START4 )
+	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_START4 ) PORT_NAME( "Right 2 Players Start" )
 
 	PORT_START
 	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_UNKNOWN )
@@ -198,65 +266,26 @@ INPUT_PORTS_END
 
 
 
-static const gfx_layout charlayout =
+/*************************************
-{
+ *
-	8,8,
+ *  Machine driver
-	256,
+ *
-	2,
+ *************************************/
-	{ 0, 4 },
-	{ 8*8+0, 8*8+1, 8*8+2, 8*8+3, 0, 1, 2, 3 },
-	{ 0*8, 1*8, 2*8, 3*8, 4*8, 5*8, 6*8, 7*8 },
-	16*8
-};
-
-
-static const gfx_layout spritelayout =
-{
-	16,16,
-	128,
-	2,
-	{ 0, 1 },
-	{ 0*2, 1*2, 2*2, 3*2, 4*2, 5*2, 6*2, 7*2, 8*2, 9*2, 10*2, 11*2, 12*2, 13*2, 14*2, 15*2 },
-	{ 0*32, 1*32, 2*32, 3*32, 4*32, 5*32, 6*32, 7*32, 8*32, 9*32, 10*32, 11*32, 12*32, 13*32, 14*32, 15*32 },
-	16*32
-};
-
-static GFXDECODE_START( 20pacgal )
-	/* the game dynamically modifies these */
-	GFXDECODE_ENTRY( 0, 0, charlayout,   0, 64 )
-	GFXDECODE_ENTRY( 0, 0, spritelayout, 0, 64 )
-GFXDECODE_END
-
-static const struct namco_interface namco_interface =
-{
-	3,	/* number of voices */
-	-1,	/* memory region */
-};
 
 static MACHINE_DRIVER_START( 20pacgal )
 
+	MDRV_DRIVER_DATA(_20pacgal_state)
+
 	/* basic machine hardware */
 	MDRV_CPU_ADD(Z180,20000000)	/* 20MHz ??? Needs to be verified! */
 	MDRV_CPU_PROGRAM_MAP(20pacgal_map,0)
-	MDRV_CPU_IO_MAP(20pacgal_port,0)
+	MDRV_CPU_IO_MAP(20pacgal_io_map,0)
 	MDRV_CPU_VBLANK_INT(irq0_line_assert,1)
 
-	MDRV_SCREEN_REFRESH_RATE(60)
-	MDRV_SCREEN_VBLANK_TIME(DEFAULT_60HZ_VBLANK_DURATION)
-
 	MDRV_NVRAM_HANDLER(eeprom)
 
 	/* video hardware */
-	MDRV_VIDEO_ATTRIBUTES(VIDEO_TYPE_RASTER)
+	MDRV_IMPORT_FROM(20pacgal_video)
-	MDRV_SCREEN_FORMAT(BITMAP_FORMAT_INDEXED16)
-	MDRV_SCREEN_SIZE(36*8, 28*8)
-	MDRV_SCREEN_VISIBLE_AREA(0*8, 36*8-1, 0*8, 28*8-1)
-	MDRV_GFXDECODE(20pacgal)
-	MDRV_PALETTE_LENGTH(0x1000)
-	MDRV_COLORTABLE_LENGTH(0x100)
-	MDRV_PALETTE_INIT(20pacgal)
-	MDRV_VIDEO_START(20pacgal)
-	MDRV_VIDEO_UPDATE(20pacgal)
 
 	/* sound hardware */
 	MDRV_SPEAKER_STANDARD_MONO("mono")
@@ -271,14 +300,14 @@ MACHINE_DRIVER_END
 
 
 
-/***************************************************************************
+/*************************************
-
+ *
-  Game driver(s)
+ *  ROM definition
-
+ *
-***************************************************************************/
+ *************************************/
 
 ROM_START( 20pacgal )
-	ROM_REGION( 0x100000, REGION_CPU1, 0 )	/* 1024k for Z180 address space */
+	ROM_REGION( 0x100000, REGION_CPU1, 0 )
 	ROM_LOAD( "20th_101.u13", 0x00000, 0x40000, CRC(77159582) SHA1(c05e005a941cbdc806dcd76b315069362c792a72) )
 
 	ROM_REGION( 0x8000, REGION_PROMS, 0 )	/* palette */
@@ -287,4 +316,10 @@ ROM_END
 
 
 
+/*************************************
+ *
+ *  Game driver
+ *
+ *************************************/
+
 GAME( 2000, 20pacgal, 0, 20pacgal, 20pacgal, 0, ROT90, "Namco", "Ms. Pac-Man/Galaga - 20 Year Reunion", GAME_IMPERFECT_GRAPHICS )

src/mame/includes/20pacgal.h

@@ -0,0 +1,29 @@
+/***************************************************************************
+
+    Ms.Pac-Man/Galaga - 20 Year Reunion hardware
+
+    driver by Nicola Salmoria
+
+***************************************************************************/
+
+
+typedef struct __20pacgal_state _20pacgal_state;
+struct __20pacgal_state
+{
+	/* memory pointers */
+	UINT8 *char_gfx_ram;
+	UINT8 *sprite_gfx_ram;
+	UINT8 *video_ram;
+	UINT8 *sprite_ram;
+	UINT8 *sprite_color_lookup;
+	UINT8 *flip_screen;
+
+	/* machine state */
+	UINT8 game_selected;	/* 0 = Ms. Pac-Man, 1 = Galaga */
+};
+
+
+
+/*----------- defined in video/20pacgal.c -----------*/
+
+MACHINE_DRIVER_EXTERN( 20pacgal_video );

src/mame/video/20pacgal.c

@@ -1,204 +1,322 @@
+/***************************************************************************
+
+    Ms.Pac-Man/Galaga - 20 Year Reunion hardware
+
+    driver by Nicola Salmoria
+
+***************************************************************************/
+
 #include "driver.h"
-#include "deprecat.h"
+#include "20pacgal.h"
+
+
+#define SCREEN_HEIGHT	(224)
+#define SCREEN_WIDTH	(288)
+#define NUM_PENS		(0x1000)
 
 
 
-UINT8 *pacgal_charram,*pacgal_sprram;
+/*************************************
-UINT8 *pacgal_videoram,*pacgal_videoram2;
+ *
+ *  Palette handling
+ *
+ *************************************/
 
-static mame_bitmap *chr_bitmap;
+static void get_pens(const _20pacgal_state *state, pen_t *pens)
-static int palbank;
-static int active_game;
-
-
-
-static void switch_palette(running_machine *machine)
 {
-	int i;
+	offs_t offs;
-	UINT8 *color_prom = memory_region(REGION_PROMS) + 0x1000 * palbank;
+	UINT8 *color_prom = memory_region(REGION_PROMS) + (NUM_PENS * state->game_selected);
 
-	for (i = 0;i < machine->drv->total_colors;i++)
+	for (offs = 0; offs < NUM_PENS ;offs++)
 	{
 		int bit0,bit1,bit2,r,g,b;
 
-
 		/* red component */
 		bit0 = (*color_prom >> 0) & 0x01;
 		bit1 = (*color_prom >> 1) & 0x01;
 		bit2 = (*color_prom >> 2) & 0x01;
 		r = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
+
 		/* green component */
 		bit0 = (*color_prom >> 3) & 0x01;
 		bit1 = (*color_prom >> 4) & 0x01;
 		bit2 = (*color_prom >> 5) & 0x01;
 		g = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
+
 		/* blue component */
 		bit0 = 0;
 		bit1 = (*color_prom >> 6) & 0x01;
 		bit2 = (*color_prom >> 7) & 0x01;
 		b = 0x21 * bit0 + 0x47 * bit1 + 0x97 * bit2;
 
-		palette_set_color(machine,i,MAKE_RGB(r,g,b));
+		pens[offs] = MAKE_RGB(r, g, b);
+
 		color_prom++;
 	}
 }
 
-PALETTE_INIT( 20pacgal )
+
+ static void do_pen_lookup(const _20pacgal_state *state, mame_bitmap *bitmap, const rectangle *cliprect)
 {
-	palbank = 0;
+	int y, x;
-	switch_palette(machine);
+	pen_t pens[NUM_PENS];
+
+	get_pens(state, pens);
+
+	for (y = cliprect->min_y; y <= cliprect->max_y; y++)
+		for(x = cliprect->min_x; x <= cliprect->max_x; x++)
+			*BITMAP_ADDR32(bitmap, y, x) = pens[*BITMAP_ADDR32(bitmap, y, x)];
 }
 
 
 
-VIDEO_START( 20pacgal )
+/*************************************
+ *
+ *  Sprite drawing
+ *
+ *************************************/
+
+static void draw_sprite(const _20pacgal_state *state, mame_bitmap *bitmap, int y, int x,
+						UINT8 code, UINT8 color, int flip_y, int flip_x)
 {
-	chr_bitmap = auto_bitmap_alloc(machine->screen[0].width,machine->screen[0].height,machine->screen[0].format);
+	int sy;
-}
 
+	offs_t pen_base = (color & 0x3f) << 2;
 
+	if (flip_y)
+		y = y + 0x0f;
 
-WRITE8_HANDLER( pacgal_lookup_w )
+	if (flip_x)
-{
+		x = x + 0x0f;
-	/* palette hacks! */
-	((UINT16 *)Machine->game_colortable)[offset] = data & 0x0f;
-	((pen_t *)Machine->remapped_colortable)[offset] = Machine->pens[data & 0x0f];
-}
 
-WRITE8_HANDLER( pacgal_active_game_w )
+	/* for each row in the sprite */
-{
+	for (sy = 0; sy < 0x10; sy++)
-	active_game = data & 1;
-
-	if (!active_game)
-		memcpy(pacgal_videoram2,memory_region(REGION_CPU1)+0x8000,0x2000);
-
-	if (palbank != active_game)
 	{
-		palbank = active_game;
+		int x_sav = x;
-		switch_palette(Machine);
+
+		if ((y >= 0) && (y < SCREEN_HEIGHT))
+		{
+			int sx;
+			UINT32 data;
+
+			offs_t gfx_offs = ((code & 0x7f) << 6) | (sy << 2);
+
+			/* address mangling */
+			gfx_offs = (gfx_offs & 0x1f83) | ((gfx_offs & 0x003c) << 1) | ((gfx_offs & 0x0040) >> 4);
+
+			data = (state->sprite_gfx_ram[gfx_offs + 0] << 24) |
+				   (state->sprite_gfx_ram[gfx_offs + 1] << 16) |
+				   (state->sprite_gfx_ram[gfx_offs + 2] << 8) |
+				   (state->sprite_gfx_ram[gfx_offs + 3] << 0);
+
+			/* for each pixel in the row */
+			for (sx = 0; sx < 0x10; sx++)
+			{
+				if ((x >= 0) && (x < SCREEN_WIDTH))
+				{
+					offs_t pen = (data & 0xc0000000) >> 30;
+					UINT8 col;
+
+					col = state->sprite_color_lookup[pen_base | pen] & 0x0f;
+
+					/* pen bits A0-A3 */
+					if (col)
+						*BITMAP_ADDR32(bitmap, y, x) = (*BITMAP_ADDR32(bitmap, y, x) & 0xff0) | col;
+				}
+
+				/* next pixel */
+				if (flip_x)
+					x = x - 1;
+				else
+					x = x + 1;
+
+				data = data << 2;
+			}
+		}
+
+		/* next row */
+		if (flip_y)
+			y = y - 1;
+		else
+			y = y + 1;
+
+		x = x_sav;
 	}
 }
 
-WRITE8_HANDLER( pacgal_videoram2_w )
-{
-	if (active_game)
-		pacgal_videoram2[offset] = data;
-}
 
-WRITE8_HANDLER( pacgal_charram_w )
+static void draw_sprites(const _20pacgal_state *state, mame_bitmap *bitmap)
-{
-	pacgal_charram[offset] = data;
-
-	decodechar(Machine->gfx[0],offset/16,pacgal_charram);
-}
-
-WRITE8_HANDLER( pacgal_sprram_w )
-{
-	offset = (offset & 0x1f83) | ((offset & 0x078) >> 1) | ((offset & 0x004) << 4);
-	pacgal_sprram[offset] = data;
-
-	decodechar(Machine->gfx[1],offset/64,pacgal_sprram);
-}
-
-
-
-static void draw_sprites(running_machine *machine, mame_bitmap *bitmap, const rectangle *cliprect )
 {
 	int offs;
 
-
+	for (offs = 0x80 - 2; offs >= 0; offs -= 2)
-	for (offs = 0x80-2;offs >= 0;offs-=2)
 	{
-		static const int gfx_offs[2][2] =
+		static const int code_offs[2][2] =
 		{
 			{ 0, 1 },
 			{ 2, 3 }
 		};
-		int sprite = spriteram[offs + 0x000] & 0x7f;
+		int x, y;
-		int color = spriteram[offs + 0x001] & 0x3f;
-		int sx = spriteram[offs + 0x081] - 41 + 0x100*(spriteram[offs + 0x101] & 3);
-		int sy = 256 - spriteram[offs + 0x080] + 1;
-		int flipx = (spriteram[offs + 0x100] & 0x01);
-		int flipy = (spriteram[offs + 0x100] & 0x02) >> 1;
-		int sizex = (spriteram[offs + 0x100] & 0x04) >> 2;
-		int sizey = (spriteram[offs + 0x100] & 0x08) >> 3;
-		int x,y;
 
-		if (flip_screen)
+		UINT8 code = state->sprite_ram[offs + 0x000];
+		UINT8 color = state->sprite_ram[offs + 0x001];
+
+		int sx = state->sprite_ram[offs + 0x081] - 41 + 0x100*(state->sprite_ram[offs + 0x101] & 3);
+		int sy = 256 - state->sprite_ram[offs + 0x080] + 1;
+
+		int flip_x = (state->sprite_ram[offs + 0x100] & 0x01) >> 0;
+		int flip_y = (state->sprite_ram[offs + 0x100] & 0x02) >> 1;
+		int size_x = (state->sprite_ram[offs + 0x100] & 0x04) >> 2;
+		int size_y = (state->sprite_ram[offs + 0x100] & 0x08) >> 3;
+
+		sy = sy - (16 * size_y);
+		sy = (sy & 0xff) - 32;	/* fix wraparound */
+
+		/* only Galaga appears to be effected by the global flip state */
+		if (state->game_selected && (state->flip_screen[0] & 0x01))
 		{
-			flipx ^= 1;
+			flip_x = !flip_x;
-			flipy ^= 1;
+			flip_y = !flip_y;
 		}
 
-		sy -= 16 * sizey;
+		for (y = 0; y <= size_y; y++)
-		sy = (sy & 0xff) - 32;	// fix wraparound
+			for (x = 0; x <= size_x; x++)
-
+				draw_sprite(state, bitmap,
-		for (y = 0;y <= sizey;y++)
+							sy + (16 * y), sx + (16 * x),
-		{
+							code + code_offs[y ^ (size_y * flip_y)][x ^ (size_x * flip_x)],
-			for (x = 0;x <= sizex;x++)
-			{
-				drawgfx(bitmap,machine->gfx[1],
-					sprite + gfx_offs[y ^ (sizey * flipy)][x ^ (sizex * flipx)],
 							color,
-					flipx,flipy,
+							flip_y, flip_x);
-					sx + 16*x, sy + 16*y,
-					cliprect,TRANSPARENCY_COLOR,0);
 	}
+}
+
+
+
+/*************************************
+ *
+ *  Character map drawing
+ *
+ *************************************/
+
+static void draw_chars(const _20pacgal_state *state, mame_bitmap *bitmap)
+{
+	offs_t offs;
+
+	int flip = state->flip_screen[0] & 0x01;
+
+	/* for each byte in the video RAM */
+	for (offs = 0; offs < 0x400; offs++)
+	{
+		int sy;
+		int y, x;
+
+		UINT8 *gfx = &state->char_gfx_ram[state->video_ram[0x0000 | offs] << 4];
+		UINT32 color_base = (state->video_ram[0x0400 | offs] & 0x3f) << 2;
+
+		/* map the offset to (x, y) character coordinates */
+		if ((offs & 0x03c0) == 0)
+		{
+			y = (offs & 0x1f) - 2;
+			x = (offs >> 5) + 34;
+		}
+		else if ((offs & 0x03c0) == 0x3c0)
+		{
+			y = (offs & 0x1f) - 2;
+			x = (offs >> 5) - 30;
+		}
+		else
+		{
+			y = (offs >> 5) - 2;
+			x = (offs & 0x1f) + 2;
+		}
+
+		if ((y < 0) || (y > 27)) continue;
+
+		/* conver to pixel coordinates */
+		y = y << 3;
+		x = x << 3;
+
+		if (flip)
+		{
+			y = SCREEN_HEIGHT - 1 - y;
+			x = SCREEN_WIDTH - 1 - x;
+		}
+
+		/* for each row in the character */
+		for (sy = 0; sy < 8; sy++)
+		{
+			int sx;
+			int x_sav = x;
+
+			UINT16 data = (gfx[8] << 8) | gfx[0];
+
+			/* for each pixel in the row */
+			for (sx = 0; sx < 8; sx++)
+			{
+				UINT32 col = ((data & 0x8000) >> 14) | ((data & 0x0800) >> 11);
+
+				/* pen bits A4-A11 */
+				*BITMAP_ADDR32(bitmap, y, x) = (color_base | col) << 4;
+
+				/* next pixel */
+				if (flip)
+					x = x - 1;
+				else
+					x = x + 1;
+
+				if (sx == 0x03)
+					data = data << 5;
+				else
+					data = data << 1;
+			}
+
+			/* next row */
+			if (flip)
+				y = y - 1;
+			else
+				y = y + 1;
+
+			x = x_sav;
+
+			gfx = gfx + 1;
 		}
 	}
 }
 
-VIDEO_UPDATE( 20pacgal )
+
+
+/*************************************
+ *
+ *  Video update
+ *
+ *************************************/
+
+static VIDEO_UPDATE( 20pacgal )
 {
-	int x,y;
+	const _20pacgal_state *state = machine->driver_data;
 
-	for (y = 0;y < 32;y++)
+	draw_chars(state, bitmap);
-	{
+	draw_sprites(state, bitmap);
-		for (x = 0;x < 32;x++)
+	do_pen_lookup(state, bitmap, cliprect);
-		{
-			int sx,sy;
-			if (y < 2)
-			{
-				sy = x-2;
-				sx = 34+y;
-			}
-			else if (y >= 30)
-			{
-				sy = x-2;
-				sx = y-30;
-			}
-			else
-			{
-				sy = y-2;
-				sx = x+2;
-			}
-
-			if (active_game)
-			{
-				drawgfx(chr_bitmap,machine->gfx[0],
-						pacgal_videoram2[y*32 + x] + 0xa00,
-						(pacgal_videoram2[0x400 + y*32 + x] & 0x3f) * 4,
-						0,0,
-						8*sx,8*sy,
-						cliprect,TRANSPARENCY_NONE_RAW,0);
-			}
-			else
-			{
-				drawgfx(chr_bitmap,machine->gfx[0],
-						pacgal_videoram[y*32 + x] + 0xa00,
-						(pacgal_videoram[0x400 + y*32 + x] & 0x3f) * 4,
-						0,0,
-						8*sx,8*sy,
-						cliprect,TRANSPARENCY_NONE_RAW,0);
-			}
-		}
-	}
-
-	fillbitmap(bitmap,0,NULL);
-
-	draw_sprites(machine,bitmap,cliprect);
-
-	copybitmap(bitmap, chr_bitmap, flip_screen, flip_screen, 0, 0, cliprect, TRANSPARENCY_BLEND_RAW, 4);
 
 	return 0;
 }
+
+
+
+/*************************************
+ *
+ *  Machine driver
+ *
+ *************************************/
+
+MACHINE_DRIVER_START( 20pacgal_video )
+
+	MDRV_VIDEO_ATTRIBUTES(VIDEO_TYPE_RASTER)
+	MDRV_VIDEO_UPDATE(20pacgal)
+
+	MDRV_SCREEN_REFRESH_RATE(60)
+	MDRV_SCREEN_VBLANK_TIME(DEFAULT_60HZ_VBLANK_DURATION)
+	MDRV_SCREEN_FORMAT(BITMAP_FORMAT_RGB32)
+	MDRV_SCREEN_SIZE(SCREEN_WIDTH, SCREEN_HEIGHT)
+	MDRV_SCREEN_VISIBLE_AREA(0, SCREEN_WIDTH - 1, 0, SCREEN_HEIGHT - 1)
+MACHINE_DRIVER_END