src/utils/print.c


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#include "print.h"
#include "types.h"

#define MAX_COL 80
#define MAX_LINE 25

char *video=(char *)0xB8000;
u8 col=0;
u8 line=0;


void putchar(char c){
  // Print char
  video[col*2+MAX_COL*line*2]=c;
  // Refresh location
  col+=1;
  if(col>= MAX_COL){
    col=0;
    line+=1;
    if(line>=MAX_LINE){
      line=MAX_LINE-1;
      scrollup();
    }
  }
}

void print(char *str){
  int i=0;
  while(str[i]!='\0'){
    putchar(str[i]);
    i++;
  }
}

void clear(){
  for(char i=0;i<MAX_LINE;i++){
    scrollup();
  }
}

void scrollup(){
  // Move line up
  for(char i=1;i<=MAX_LINE;i++){
    for(char j=0;j<=MAX_COL;j++)
      video[j*2+MAX_COL*(i-1)*2]=video[j*2+MAX_COL*i*2];
  }
  // Clear last line
  for(char i=0;i<=MAX_COL;i++){
    video[col*2+MAX_COL*(MAX_LINE-1)*2]='\0';
  }
}