exprraid.c

这个是延伸mame的在wince平台下的游戏模拟器的代码

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

Express Raider - (c) 1986 Data East USA

Ernesto Corvi
[e-mail]

Memory Map:
Main CPU: ( 6502 )
0000-05ff RAM
0600-07ff Sprites
0800-0bff Videoram
0c00-0fff Colorram
1800-1800 DSW 0
1801-1801 Controls
1802-1802 Coins
1803-1803 DSW 1
2100-2100 Sound latch write
2800-2801 Protection
3800-3800 VBblank ( bootleg only )
4000-ffff MRA_ROM

Sound Cpu: ( 6809 )
0000-1fff RAM
2000-2001 YM2203
4000-4001 YM3526
6000-6000 Sound latch read
8000-ffff ROM

NOTES:
The main 6502 cpu is a custom one. The differences with a regular 6502 is as follows:
- Extra opcode ( $4b00 ), wich i think reads an external port. VBlank irq is on bit 1 ( 0x02 ).
- Reset, IRQ and NMI vectors are moved.

Also, there was some protection circuitry wich is now emulated.

The way i dealt with the custom opcode was to change it to return memory
position $ff (wich i verified is not used by the game). And i hacked in
a read handler wich returns the vblank on bit 1. It's an ugly hack, but
works fine.

The bootleg version patched the rom to get rid of the extra opcode ( bootlegs
used a regular 6502 ), the vectors hardcoded in place, and also had the
protection cracked.

The background tiles had a very ugly encoding. It was so ugly that our
decode gfx routine will not be able to decode it without some little help.
So thats why exprraid_gfx_expand() is there. Many thanks to Phil
Stroffolino, who figured out the encoding.

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

#include "driver.h"
#include "vidhrdw/generic.h"
#include "M6809/M6809.h"

/* from vidhrdw */
extern unsigned char *exprraid_bgcontrol;
void exprraid_vh_screenrefresh(struct osd_bitmap *bitmap,int full_refresh);
void exprraid_vh_convert_color_prom(unsigned char *palette, unsigned short *colortable,const unsigned char *color_prom);


/*****************************************************************************************/
/* Emulate Protection ( only for original express raider, code is cracked on the bootleg */
/*****************************************************************************************/

static int exprraid_prot_0_r(int offset)
{
	unsigned char *RAM = Machine->memory_region[0];

	return RAM[0x02a9];
}

static int exprraid_prot_1_r(int offset)
{
	return 0x02;
}

static void sound_cpu_command_w( int offset, int v )
{
    soundlatch_w(0,v);
    cpu_cause_interrupt(1,M6809_INT_NMI);
}

static int vblank_r( int offset ) {
	int val = readinputport( 0 );

	if ( ( val & 0x02 ) )
		cpu_spin();

	return val;
}

static struct MemoryReadAddress readmem[] =
{
	{ 0x00ff, 0x00ff, vblank_r }, /* HACK!!!! see exprraid_decode_rom below */
    { 0x0000, 0x05ff, MRA_RAM },
    { 0x0600, 0x07ff, MRA_RAM }, /* sprites */
    { 0x0800, 0x0bff, videoram_r },
    { 0x0c00, 0x0fff, colorram_r },
    { 0x1800, 0x1800, input_port_1_r }, /* DSW 0 */
    { 0x1801, 0x1801, input_port_2_r }, /* Controls */
    { 0x1802, 0x1802, input_port_3_r }, /* Coins */
    { 0x1803, 0x1803, input_port_4_r }, /* DSW 1 */
	{ 0x2800, 0x2800, exprraid_prot_0_r }, /* protection */
	{ 0x2801, 0x2801, exprraid_prot_1_r }, /* protection */
    { 0x3800, 0x3800, vblank_r }, /* vblank on bootleg */
    { 0x4000, 0xffff, MRA_ROM },
    { -1 }  /* end of table */
};

static struct MemoryWriteAddress writemem[] =
{
    { 0x0000, 0x05ff, MWA_RAM },
    { 0x0600, 0x07ff, MWA_RAM, &spriteram, &spriteram_size }, /* sprites */
    { 0x0800, 0x0bff, videoram_w, &videoram, &videoram_size },
    { 0x0c00, 0x0fff, colorram_w, &colorram },
    { 0x2001, 0x2001, sound_cpu_command_w },
    { 0x2800, 0x2807, MWA_RAM, &exprraid_bgcontrol },
    { 0x4000, 0xffff, MWA_ROM },
    { -1 }  /* end of table */
};

static struct MemoryReadAddress sub_readmem[] =
{
    { 0x0000, 0x1fff, MRA_RAM },
    { 0x2000, 0x2000, YM2203_status_port_0_r },
	{ 0x2001, 0x2001, YM2203_read_port_0_r },
    { 0x4000, 0x4000, YM3526_status_port_0_r },
	{ 0x6000, 0x6000, soundlatch_r },
    { 0x8000, 0xffff, MRA_ROM },
    { -1 }  /* end of table */
};

static struct MemoryWriteAddress sub_writemem[] =
{
    { 0x0000, 0x1fff, MWA_RAM },
    { 0x2000, 0x2000, YM2203_control_port_0_w },
	{ 0x2001, 0x2001, YM2203_write_port_0_w },
    { 0x4000, 0x4000, YM3526_control_port_0_w },
    { 0x4001, 0x4001, YM3526_write_port_0_w },
    { 0x8000, 0xffff, MWA_ROM },
    { -1 }  /* end of table */
};

INPUT_PORTS_START( input_ports )
	PORT_START /* IN 0 - 0x3800 */
	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_VBLANK )

	PORT_START /* DSW 0 - 0x1800 */
	PORT_DIPNAME( 0x03, 0x03, "Coin A", IP_KEY_NONE )
	PORT_DIPSETTING(    0x00, "2 Coins/1 Credit" )
	PORT_DIPSETTING(    0x03, "1 Coin/1 Credit" )
	PORT_DIPSETTING(    0x02, "1 Coin/2 Credits" )
	PORT_DIPSETTING(    0x01, "1 Coin/3 Credits" )
	PORT_DIPNAME( 0x0c, 0x0c, "Coin B", IP_KEY_NONE )
	PORT_DIPSETTING(    0x00, "2 Coins/1 Credit" )
	PORT_DIPSETTING(    0x0c, "1 Coin/1 Credit" )
	PORT_DIPSETTING(    0x08, "1 Coin/2 Credits" )
	PORT_DIPSETTING(    0x04, "1 Coin/3 Credits" )
	PORT_DIPNAME( 0x10, 0x10, "Unknown", IP_KEY_NONE )
	PORT_DIPSETTING(    0x10, "Off" )
	PORT_DIPSETTING(    0x00, "On" )
	PORT_DIPNAME( 0x20, 0x20, "Flip Screen", IP_KEY_NONE )
	PORT_DIPSETTING(    0x20, "Off" )
	PORT_DIPSETTING(    0x00, "On" )
	PORT_DIPNAME( 0x40, 0x00, "Cabinet", IP_KEY_NONE )
	PORT_DIPSETTING(    0x00, "Upright" )
	PORT_DIPSETTING(    0x40, "Cocktail" )
	PORT_DIPNAME( 0x80, 0x80, "Unknown", IP_KEY_NONE )
	PORT_DIPSETTING(    0x80, "Off" )
	PORT_DIPSETTING(    0x00, "On" )

	PORT_START /* IN 1 - 0x1801 */
	PORT_BIT( 0x01, IP_ACTIVE_LOW, IPT_JOYSTICK_RIGHT | IPF_8WAY )
	PORT_BIT( 0x02, IP_ACTIVE_LOW, IPT_JOYSTICK_LEFT | IPF_8WAY )
	PORT_BIT( 0x04, IP_ACTIVE_LOW, IPT_JOYSTICK_UP | IPF_8WAY )
	PORT_BIT( 0x08, IP_ACTIVE_LOW, IPT_JOYSTICK_DOWN | IPF_8WAY )
	PORT_BIT( 0x10, IP_ACTIVE_LOW, IPT_BUTTON1 )
	PORT_BIT( 0x20, IP_ACTIVE_LOW, IPT_BUTTON2 )
	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_START1 )
	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_START2 )

	PORT_START /* IN 2 - 0x1802 */
	PORT_BIT( 0x40, IP_ACTIVE_LOW, IPT_COIN1 )
	PORT_BIT( 0x80, IP_ACTIVE_LOW, IPT_COIN2 )

	PORT_START /* IN 3 - 0x1803 */
	PORT_DIPNAME( 0x03, 0x03, "Lives", IP_KEY_NONE )
	PORT_DIPSETTING(    0x01, "1" )
	PORT_DIPSETTING(    0x03, "3" )
	PORT_DIPSETTING(    0x02, "5" )
	PORT_BITX( 0,       0x00, IPT_DIPSWITCH_SETTING | IPF_CHEAT, "Infinite", IP_KEY_NONE, IP_JOY_NONE, 0 )
	PORT_DIPNAME( 0x04, 0x04, "Bonus Life", IP_KEY_NONE )
	PORT_DIPSETTING(    0x04, "Every 50000" )
	PORT_DIPSETTING(    0x00, "50000 80000" )
	PORT_DIPNAME( 0x18, 0x18, "Difficulty", IP_KEY_NONE )
	PORT_DIPSETTING(    0x10, "Easy" )
	PORT_DIPSETTING(    0x18, "Normal" )
	PORT_DIPSETTING(    0x08, "Hard" )
	PORT_DIPSETTING(    0x00, "Hardest" )
	PORT_DIPNAME( 0x20, 0x20, "Demo Sounds", IP_KEY_NONE )
	PORT_DIPSETTING(    0x00, "Off" )
	PORT_DIPSETTING(    0x20, "On" )
	PORT_DIPNAME( 0x40, 0x40, "Unknown", IP_KEY_NONE )	/* This one has to be set for coin up */
	PORT_DIPSETTING(    0x40, "Off" )
	PORT_DIPSETTING(    0x00, "On" )
	PORT_DIPNAME( 0x80, 0x80, "Unknown", IP_KEY_NONE )
	PORT_DIPSETTING(    0x80, "Off" )
	PORT_DIPSETTING(    0x00, "On" )
INPUT_PORTS_END



static struct GfxLayout charlayout =
{
	8,8,	/* 8*8 characters */
	1024,	/* 1024 characters */
	2,	/* 2 bits per pixel */
	{ 0, 4 },	/* the bitplanes are packed in the same byte */
	{ (0x2000*8)+0, (0x2000*8)+1, (0x2000*8)+2, (0x2000*8)+3, 0, 1, 2, 3 },
	{ 0*8, 1*8, 2*8, 3*8, 4*8, 5*8, 6*8, 7*8 },
	8*8	/* every char takes 8 consecutive bytes */
};

static struct GfxLayout spritelayout =
{
	16,16,	/* 16*16 sprites */
	2048,	/* 2048 sprites */
	3,	/* 3 bits per pixel */
	{ 2*2048*32*8, 2048*32*8, 0 },	/* the bitplanes are separated */
	{ 128+0, 128+1, 128+2, 128+3, 128+4, 128+5, 128+6, 128+7, 0, 1, 2, 3, 4, 5, 6, 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	/* every char takes 32 consecutive bytes */
};

static struct GfxLayout tile1 =
{
	16,16,	/* 16*16 tiles */
	128,	/* 128 tiles */
	3,	/* 3 bits per pixel */
	{ 4, 0x10000*8+0, 0x10000*8+4 },
	{ 0, 1, 2, 3, 1024*32*2,1024*32*2+1,1024*32*2+2,1024*32*2+3,
		128+0,128+1,128+2,128+3,128+1024*32*2,128+1024*32*2+1,128+1024*32*2+2,128+1024*32*2+3 }, /* BOGUS */
	{ 0*8,1*8,2*8,3*8,4*8,5*8,6*8,7*8,
		64+0*8,64+1*8,64+2*8,64+3*8,64+4*8,64+5*8,64+6*8,64+7*8 },
	32*8
};

static struct GfxLayout tile2 =
{
	16,16,	/* 16*16 tiles */
	128,	/* 128 tiles */
	3,	/* 3 bits per pixel */
	{ 0, 0x11000*8+0, 0x11000*8+4  },
	{ 0, 1, 2, 3, 1024*32*2,1024*32*2+1,1024*32*2+2,1024*32*2+3,
		128+0,128+1,128+2,128+3,128+1024*32*2,128+1024*32*2+1,128+1024*32*2+2,128+1024*32*2+3 }, /* BOGUS */
	{ 0*8,1*8,2*8,3*8,4*8,5*8,6*8,7*8,
		64+0*8,64+1*8,64+2*8,64+3*8,64+4*8,64+5*8,64+6*8,64+7*8 },
	32*8
};


static struct GfxDecodeInfo gfxdecodeinfo[] =
{
    { 1, 0x00000, &charlayout,   128, 2 }, /* characters */
    { 1, 0x04000, &spritelayout,  64, 8 }, /* sprites */
    { 1, 0x34000, &tile1,          0, 4 }, /* background tiles */
    { 1, 0x34000, &tile2,          0, 4 },
    { 1, 0x38000, &tile1,          0, 4 },
    { 1, 0x38000, &tile2,          0, 4 },
    { 1, 0x3c000, &tile1,          0, 4 },
    { 1, 0x3c000, &tile2,          0, 4 },
    { 1, 0x40000, &tile1,          0, 4 },
    { 1, 0x40000, &tile2,          0, 4 },
    { -1 } /* end of array */
};

static struct YM2203interface ym2203_interface =
{
    1,      /* 1 chip */
    1500000,        /* 1.5 MHz ??? */
    { YM2203_VOL(30,30) },
    { 0 },
    { 0 },
    { 0 },
    { 0 }
};

static struct YM3526interface ym3526_interface =
{
    1,                      /* 1 chip (no more supported) */
	3600000,	/* 3.600000 MHz ? (partially supported) */
    { 255 }         /* (not supported) */
};

static int exprraid_interrupt(void)
{
	static int coin = 0;

	if ( ( ~readinputport( 3 ) ) & 0xc0 ) {
		if ( coin == 0 ) {
			coin = 1;
			return nmi_interrupt();
		}
	} else
		coin = 0;

	return ignore_interrupt();
}

static struct MachineDriver machine_driver =
{
	/* basic machine hardware */
	{
		{
			CPU_M6502,
			4000000,        /* 4 Mhz ??? */
			0,
			readmem,writemem,0,0,
			exprraid_interrupt, 1
		},