#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "../port/error.h" enum {	Black,	Blue,	Green,	Cyan,	Red,	Magenta,	Brown,	Grey, 	Bright = 0x08,	Blinking = 0x80, 	Yellow = Bright|Brown,	White = Bright|Grey,};	enum {	Width		= 80*2,	Height		= 25, 	Attr		= (Black<<4)|Grey,	/* high nibble background						 * low foreground						 */}; #define CGASCREENBASE	((uchar*)KADDR(0xB8000)) static int cgapos;static Lock cgascreenlock; static ucharcgaregr(int index){	outb(0x3D4, index);	return inb(0x3D4+1) & 0xFF;} static voidcgaregw(int index, int data){	outb(0x3D4, index);	outb(0x3D4+1, data);} static voidmovecursor(void){	cgaregw(0x0E, (cgapos/2>>8) & 0xFF);	cgaregw(0x0F, cgapos/2 & 0xFF);	CGASCREENBASE[cgapos+1] = Attr;} static voidcgascreenputc(int c){	int i;	uchar *p; 	if(c == '\n'){		cgapos = cgapos/Width;		cgapos = (cgapos+1)*Width;	}	else if(c == '\t'){		i = 8 - ((cgapos/2)&7);		while(i-->0)			cgascreenputc(' ');	}	else if(c == '\b'){		if(cgapos >= 2)			cgapos -= 2;		cgascreenputc(' ');		cgapos -= 2;	}	else{		CGASCREENBASE[cgapos++] = c;		CGASCREENBASE[cgapos++] = Attr;	}	if(cgapos >= Width*Height){		memmove(CGASCREENBASE, &CGASCREENBASE[Width], Width*(Height-1));		p = &CGASCREENBASE[Width*(Height-1)];		for(i=0; i<Width/2; i++){			*p++ = ' ';			*p++ = Attr;		}		cgapos = Width*(Height-1);	}	movecursor();} static voidcgascreenputs(char* s, int n){	if(!islo()){		/*		 * Don't deadlock trying to		 * print in an interrupt.		 */		if(!canlock(&cgascreenlock))			return;	}	else		lock(&cgascreenlock); 	while(n-- > 0)		cgascreenputc(*s++); 	unlock(&cgascreenlock);} voidscreeninit(void){ 	cgapos = cgaregr(0x0E)<<8;	cgapos |= cgaregr(0x0F);	cgapos *= 2; 	screenputs = cgascreenputs;}