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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "io.h"
enum {
Width = 160,
Height = 25,
Attr = 0x4f, /* white on blue */
};
static ulong cgabase;
#define CGASCREENBASE ((uchar*)cgabase)
static int cgapos;
static int screeninitdone;
static Lock cgascreenlock;
static uchar
cgaregr(int index)
{
outb(0x3D4, index);
return inb(0x3D4+1) & 0xFF;
}
static void
cgaregw(int index, int data)
{
outb(0x3D4, index);
outb(0x3D4+1, data);
}
static void
movecursor(void)
{
cgaregw(0x0E, (cgapos/2>>8) & 0xFF);
cgaregw(0x0F, cgapos/2 & 0xFF);
CGASCREENBASE[cgapos+1] = Attr;
}
static void
cgascreenputc(int c)
{
int i;
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));
for (i = Width*(Height-1); i < Width*Height;) {
CGASCREENBASE[i++] = 0x20;
CGASCREENBASE[i++] = Attr;
}
cgapos = Width*(Height-1);
}
movecursor();
}
void
screeninit(void)
{
cgabase = (ulong)arch->pcimem(0xB8000, 0x8000);
cgapos = cgaregr(0x0E)<<8;
cgapos |= cgaregr(0x0F);
cgapos *= 2;
screeninitdone = 1;
}
static void
cgascreenputs(char* s, int n)
{
if(!screeninitdone)
return;
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);
}
void (*screenputs)(char*, int) = cgascreenputs;
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