C PIC32 Counting

 /*
  * Author: Umut Berk Bilgiç
  * Bilkent University Computer Science - CS224 Lab 6
  * Following code demonstrates simple binary counting with variable speed
  *     and orientation controls. PORTs are modifiable as long as they follow
  *     the classic numbering scheme.
  */

// decimal int to binary string conversion for use in
// ... reverse/mirrored display.
void decTo8BinStr(int value, char* output)
{
    int i;
    for (i = 7; i >= 0; --i)
    {
        value = value >> 1;
        output[i] = (value & 1) + '0';
    }
}

// initialize variables for
int i;
const int max_count = 256;

void main() {
     AD1PCFG = 0xFFFF;  // set analog ports to digital
     DDPCON.JTAGEN = 0; // disable jtag

     TRISD = 0x0000;    // make PORTD output
     TRISE = 0xFFFF;    // make PORTE input

     PORTD = 0xFFFF;    // init PORTD to all zeros

     // E4 not pressed: normal
     // E4 pressed: mirrored
     // ** E1: high speed
     // ** E3: low speed

     while(1) // main loop
     {
         for (i = 0; i < max_count; i++)
         {
             if (PORTEbits.RE4 != 0) // normal orientation
                 PORTD = ~i;  // set LEDs to current number
             else
             {
                  char s[8];
                  decTo8BinStr(i, s);
                  PORTDbits.RD0 = ~(s[0] - '0');
                  PORTDbits.RD1 = ~(s[1] - '0');
                  PORTDbits.RD2 = ~(s[2] - '0');
                  PORTDbits.RD3 = ~(s[3] - '0');
                  PORTDbits.RD4 = ~(s[4] - '0');
                  PORTDbits.RD5 = ~(s[5] - '0');
                  PORTDbits.RD6 = ~(s[6] - '0');
                  PORTDbits.RD7 = ~(s[7] - '0');
             }

             // select delays based on given inputs at PORTE
             if (PORTEbits.RE1 == 0)
                 Delay_ms(250);
             else if (PORTEbits.RE3 == 0)
                 Delay_ms(750);
             else
                 Delay_ms(500);
         }
     }
}