Codigo contador basico 4 digitos

#include <16F84A.h>

#FUSES NOWDT                    //No Watch Dog Timer
#FUSES XT                       //Crystal osc <= 4mhz
#FUSES PUT                      //Power Up Timer
#FUSES NOPROTECT                //Code not protected from reading

#use delay(clock=4000000)

#byte portb=0x06
#byte porta=0x05
#byte trisb=0x86
#byte trisa=0x85
   const byte display[16]={0b11000000,0b11111001,0b10100100,0b10110000,0b10011001,0b10010010,0b10000010,
                           0b11111000,0b10000000,0b10010000,0b10001000,0b10000011,0b10100111,0b10100001,
                           0b10000110,0b10001110};
     byte d1,d2,d3,d4,a,i;
 void saca()
{
       a=1;

       portb=display[d1];
       porta=a;
       delay_ms(10);
       portb=0xff;
       porta=0;
       delay_ms(1);
       a<<=1;

       portb=display[d2];
       porta=a;
       delay_ms(10);
       portb=0xff;
       porta=0;
       delay_ms(1);
       a<<=1;

       portb=display[d3];
       porta=a;
       delay_ms(10);
       portb=0xff;
       porta=0;
       delay_ms(1);
       a<<=1;

       portb=display[d4];
       porta=a;
       delay_ms(10);
       portb=0xff;
       porta=0;
       delay_ms(1);
       a<<=1;
}

void main()
{
   portb=0;porta=0;set_tris_a(0x00);set_tris_b(0x00);
   d1=0;d2=0;d3=0;d4=0;
while (true)
{
   for(i=0;i<10;i++){saca();}
   d1++;
   if (d1>9){d1=0; d2++;}
   if (d2>9){d2=0;d3++;}
   if (d3>9){d3=0;d4++;}
   if (d4>9){d4=0;}

}

}