typedef struct Cursor Cursor; enum {	CURSWID = 16,	CURSHGT = 16,}; struct	Cursor{	Point	offset;	uchar	clr[CURSWID/BI2BY*CURSHGT];	uchar	set[CURSWID/BI2BY*CURSHGT];};typedef struct Cursorinfo Cursorinfo;struct Cursorinfo {	Cursor;	Lock;}; /* devmouse.c */extern void mousetrack(int, int, int, int);extern Point mousexy(void); extern void mouseaccelerate(int);extern int m3mouseputc(Queue*, int);extern int m5mouseputc(Queue*, int);extern int mouseputc(Queue*, int); extern Cursorinfo cursor;extern Cursor arrow; /* * Generic VGA registers. */enum {	MiscW		= 0x03C2,	/* Miscellaneous Output (W) */	MiscR		= 0x03CC,	/* Miscellaneous Output (R) */	Status0		= 0x03C2,	/* Input status 0 (R) */	Status1		= 0x03DA,	/* Input Status 1 (R) */	FeatureR	= 0x03CA,	/* Feature Control (R) */	FeatureW	= 0x03DA,	/* Feature Control (W) */ 	Seqx		= 0x03C4,	/* Sequencer Index, Data at Seqx+1 */	Crtx		= 0x03D4,	/* CRT Controller Index, Data at Crtx+1 */	Grx		= 0x03CE,	/* Graphics Controller Index, Data at Grx+1 */	Attrx		= 0x03C0,	/* Attribute Controller Index and Data */ 	PaddrW		= 0x03C8,	/* Palette Address Register, write */	Pdata		= 0x03C9,	/* Palette Data Register */	Pixmask		= 0x03C6,	/* Pixel Mask Register */	PaddrR		= 0x03C7,	/* Palette Address Register, read */	Pstatus		= 0x03C7,	/* DAC Status (RO) */ 	Pcolours	= 256,		/* Palette */	Pred		= 0,	Pgreen		= 1,	Pblue		= 2, 	Pblack		= 0x00,	Pwhite		= 0xFF,}; #define VGAMEM()	0xA0000#define vgai(port)		inb(port)#define vgao(port, data)	outb(port, data) extern int vgaxi(long, uchar);extern int vgaxo(long, uchar, uchar); /* */typedef struct VGAdev VGAdev;typedef struct VGAcur VGAcur;typedef struct VGAscr VGAscr; struct VGAdev {	char*	name; 	void	(*enable)(VGAscr*);	void	(*disable)(VGAscr*);	void	(*page)(VGAscr*, int);	ulong	(*linear)(VGAscr*, int*, int*);	void	(*drawinit)(VGAscr*);	int	(*fill)(VGAscr*, Rectangle, ulong);	void	(*ovlctl)(VGAscr*, Chan*, void*, int);	int	(*ovlwrite)(VGAscr*, void*, int, vlong);	void (*flush)(VGAscr*, Rectangle);}; struct VGAcur {	char*	name; 	void	(*enable)(VGAscr*);	void	(*disable)(VGAscr*);	void	(*load)(VGAscr*, Cursor*);	int	(*move)(VGAscr*, Point); 	int	doespanning;}; /* */struct VGAscr {	Lock	devlock;	VGAdev*	dev; 	VGAcur*	cur;	ulong	storage;	Cursor; 	int	useflush; 	ulong	aperture;			/* physical address */	int	isupamem;	int	apsize; 	ulong	io;				/* device specific registers */ 	ulong	colormap[Pcolours][3];	int	palettedepth; 	ulong	*mmio;	Memimage* gscreen;	Memdata* gscreendata;	Memsubfont* memdefont; 	int	(*fill)(VGAscr*, Rectangle, ulong);	int	(*scroll)(VGAscr*, Rectangle, Rectangle);	void	(*blank)(VGAscr*, int);	ulong	id;	/* internal identifier for driver use */	int isblank;	int overlayinit;}; extern VGAscr vgascreen[]; enum {	Backgnd		= 0,	/* black */}; /* mouse.c */extern void mousectl(Cmdbuf*); /* screen.c */extern int		hwaccel;	/* use hw acceleration; default on */extern int		hwblank;	/* use hw blanking; default on */extern int		panning;	/* use virtual screen panning; default off */extern void addvgaseg(char*, ulong, ulong);extern uchar* attachscreen(Rectangle*, ulong*, int*, int*, int*);extern void	flushmemscreen(Rectangle);extern int	cursoron(int);extern void	cursoroff(int);extern void	setcursor(Cursor*);extern int	screensize(int, int, int, ulong);extern int	screenaperture(int, int);extern Rectangle physgscreenr;	/* actual monitor size */extern void	blankscreen(int); /* devdraw.c */extern void	deletescreenimage(void);extern int		drawhasclients(void);extern ulong	blanktime;extern void	setscreenimageclipr(Rectangle);extern void	drawflush(void);extern int drawidletime(void); /* vga.c */extern void	vgascreenwin(VGAscr*);extern void	vgaimageinit(ulong);extern ulong	vgapcilinear(VGAscr*, int*, int*, int, int); extern void	drawblankscreen(int);extern void	vgablank(VGAscr*, int);