video.c

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#include "routix/system.h"
#include <routix/kstdio.h>
#include <drivers/video.h>

#define VIDEO   (0xb8000)
 
#define TAB_SPACES 4

unsigned char *pos = (unsigned char *) VIDEO;
unsigned char cursor_caracteristicas = 2;

#define VIDEO_LAST_LINE         3840

#define nextpos(pos)    if ( (pos+=2) > (unsigned char *) VIDEO+4000 ) {                        \
                                                        scroll_up();                                                                                    \
                                                        pos = (unsigned char *) (VIDEO + VIDEO_LAST_LINE);              \
                                                }                                                                                                               
                                                        
 

int putchar ( int a )
{
  
        // __asm__ __volatile__("cli");
                
        if ( a == '\n' ) {
                int frac;
                int newpos;
                frac = (int) (pos-VIDEO)/160;
                newpos = (VIDEO+160*(frac+1)); 
                if ( newpos >= VIDEO+4000 ) {
                        scroll_up();
                        pos = (unsigned char *) ( VIDEO + VIDEO_LAST_LINE );
                }
                else 
                        pos=(unsigned char *) newpos;
        }
        else if ( a == '\t' ) {
                int i;
                for (i=0; i<4; i++ ) 
//                      pos=nextpos(pos);
                        nextpos(pos);
        }
        else if ( a == '\b' ) {
                pos-=2;
                *pos=' ';
                *(pos+1) = cursor_caracteristicas;
        }

        else {  
                *pos = (unsigned char) a;   
                *(pos+1) = cursor_caracteristicas;
//              pos=nextpos(pos); 
                nextpos(pos);
        }

        // __asm__ __volatile__("sti");

        refresh_cursor( ((pos - (unsigned char *)VIDEO) /2) );
        
//      refresh_cursor( getvar("cursor"));
        return a;
}




int puts ( const char *s )
{
        int cantidad=0;
 
        while ( *s ) {
                putchar(*s++);
                cantidad++;
        }

        return cantidad;
}
// VIDEO_LAST_LINE                      80*24*2
/*
#define VIDEO_LAST_LINE         3840

unsigned char *nextpos ( unsigned char *posicion )
{
        unsigned char *pos=posicion;
 
        pos += 2;
        
        if ( pos >= (unsigned char *) VIDEO+4000 ) {
                scroll_up();
                pos = (unsigned char *) ( VIDEO + VIDEO_LAST_LINE );
        }
        return pos;
}
*/



void clrscr (void)
{
        int i;
        unsigned char *ptr;
        
        ptr = (unsigned char *) VIDEO;
        
        for (i=0; i<4000; i+=2 ) {
                *(ptr+i) = ' ';
                *(ptr+i+1) = 2;
        }
        
        pos = (unsigned char *) VIDEO;
}

void scroll_up ( void )
{
        unsigned char *inicio =(unsigned char *) VIDEO + 160;
        unsigned char *destino=(unsigned char *) VIDEO;
        int count;

        cli();

        __asm__ __volatile__ ("cld ; rep ; movsw" : : "c" (VIDEO_LAST_LINE),  "S" (inicio) , "D" (destino));
/*
        for ( count=0; count < VIDEO_LAST_LINE; count++ ) {
                *destino++ = *inicio++;
        }
 */     


        destino += VIDEO_LAST_LINE;
        for ( count=0; count < 80; count ++ ) {
                *destino++ = ' ';
                *destino++ = cursor_caracteristicas;
        }

        sti();
}




unsigned char *gotoxy ( int fila, int columna)
{
        if ( (fila > 25) || (columna > 80) ) { return NULL; }
                pos = (unsigned char *) (VIDEO + (fila-1)*2*80+2*(columna-1) );
        return pos;
}

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