void setup() {
  // put your setup code here, to run once:
  volatile char *dirk,*dirf,*dira,*dirb,*outf,*outk,*outa,*outb,*ink,x;
  dirk=0x107;outk=0x108;ink=0x106;dirf=0x30;outf=0x31;dira=0x21;outa=0x22;dirb=0x24;outb=0x25;
  *dirk=0xf0;*dira=0xff;*dirf=0xff;*outa=0xff;*dirb=0xff;
  volatile long row,cols,input=0,datacount=0,i;
  volatile char one,ten,hundred,thousand;
  const char keymap[4][3]={{0},{7,8,9},{4,5,6},{1,2,3}};
  const char display[]={0XC0,0XF9,0XA4,0XB0,0X99,0X92,0X82,0XF8,0X80,0X90,0X88,0X83,0XC6,0XA1,0X86,0X8E};
  while(1)
  {
    if(datacount<4){
    for(row=0;row<4;row++)
    {
      *outk=1<<(row+4);
      *outf=*ink;
      cols=(*ink&0x0f);
      if(cols!=0)
      { 
        for(i=0;i<4000;i++);//delay
        cols=*ink&0x0f;
        if(cols==0) continue;
        
        else if(*ink&0x80)
        {
          if(*ink&0x08){
            input=(input*10)+1;
            datacount++;
          }
          if(*ink&0x04){
            input=(input*10)+2;
            datacount++;
          }
          if(*ink&0x02){
            input=(input*10)+3;
            datacount++;
          }
        }

        else if(*ink&0x40)
        {
          if(*ink&0x08){
            input=(input*10)+4;
            datacount++;
          }
          if(*ink&0x04){
            input=(input*10)+5;
            datacount++;
          }
          if(*ink&0x02){
            input=(input*10)+6;
            datacount++;
          }
        }

        else if(*ink&0x20)
        {
          if(*ink&0x08){
            input=(input*10)+7;
            datacount++;
          }
          if(*ink&0x04){
            input=(input*10)+8;
            datacount++;
          }
          if(*ink&0x02){
            input=(input*10)+9;
            datacount++;
          }
        }

        else if(*ink&0x10)
        {

          if(*ink&0x04){
            input=(input*10)+0;
            datacount++;
          }
          while((*ink & 0x0f) != 0);//wait till key released
        }
      }
      }
    }
    if(datacount>=4)
    {
      volatile char led_in=input;
      one=led_in%10;
      ten=(led_in/10)%10;
      led_in/=10;
      hundred=(led_in/10)%10;
      led_in/=10;
      thousand=(led_in/10)%10;
      datacount=0;
      input=0;
    }
    *outb=0x01;
      *outa=display[thousand];
      *outa=0xff;
      for(i=0;i<1000;i++);

      *outb=0x02;
      *outa=display[hundred];
      *outa=0xff;
      for(i=0;i<1000;i++);

      *outb=0x04;
      *outa=display[ten];
      *outa=0xff;
      for(i=0;i<1000;i++);

      *outb=0x08;
      *outa=display[one];
      *outa=0xff;
      for(i=0;i<1000;i++);
  }
}