#define __MAIN_C__

#include <stdint.h>



#define AHB_LED_BASE				0x50000000
#define AHB_SW_BASE				0x50000004

// Define pointers with correct type for access to 16-bit peripherals
volatile uint16_t* LED_BASE_POINTER = (volatile uint16_t*) AHB_LED_BASE;
volatile uint16_t* SW_BASE_POINTER = (volatile uint16_t*) AHB_SW_BASE;

// LED and Switch bytes can be addressed individually
volatile uint8_t* LED_BYTES = (volatile uint8_t*) AHB_LED_BASE;
volatile uint8_t* SW_BYTES = (volatile uint8_t*) AHB_SW_BASE;

#include <stdint.h>

//////////////////////////////////////////////////////////////////
// Main Function
//////////////////////////////////////////////////////////////////

void write_leds(uint16_t value) {

  *LED_BASE_POINTER = value;

}

uint16_t read_leds(void) {

  return *LED_BASE_POINTER;

}


void write_leds_low(uint8_t value) {

  LED_BYTES[0] = value;

}


void write_leds_high(uint8_t value) {

  LED_BYTES[1] = value;

}

uint16_t read_switches(void) {

  return *SW_BASE_POINTER;

}


uint16_t read_switches_low(void) {

  return SW_BYTES[0];

}


uint16_t read_switches_high(void) {

  return SW_BYTES[1];

}

int factorial(int value) {

  if ( value == 0 ) return 1;
  else return ( value * factorial(value - 1) );

}

void delay_loop(int value) {

  volatile int i;
  for ( i = 1; i <= value; i++ )
    {};

}


int main(void) {

  int fact_in;

  write_leds( 0xA5A5 );

  while( read_switches() != 0xFFFF ){
    write_leds_low( read_switches_high() );
    write_leds_high( read_switches_low() );
  }

  write_leds( 0xA815 );

  while( read_switches() != 0x0000 ){}


  while(1){
    fact_in = read_switches_low() & 7;
    write_leds( factorial(fact_in) );
  }

}