/*----------------------------------------------------------------------------*/
#define GPIO_BASE 0x20200000
#define GPIO_FSEL 0x00
#define GPIO_FSET 0x07
#define GPIO_FCLR 0x0A
#define GPIO_ACT_LED 47
/*----------------------------------------------------------------------------*/
/** using macros :p */
#define gpio_output(x) gpio[GPIO_FSEL+(x/10)]=1<<(x%10)*3
#define gpio_clr(x) gpio[GPIO_FCLR+(x/32)]=1<<(x%32)
#define gpio_set(x) gpio[GPIO_FSET+(x/32)]=1<<(x%32)
/*----------------------------------------------------------------------------*/
/** volatile coz -O2 compiler option would otherwise kill them? */
volatile unsigned int *gpio, loop;
/*----------------------------------------------------------------------------*/
void main(void)
{
	/** point to gpio access register */
	gpio = (unsigned int*) GPIO_BASE;
	/** configure gpio as output */
	gpio_output(GPIO_ACT_LED);
	/** main loop */
	while(1)
	{
		/** clear pin! */
		gpio_clr(GPIO_ACT_LED);
		/** delay a bit to allow us see the blink! */
		for(loop=0;loop<0x200000;loop++);
		/** set pin! */
		gpio_set(GPIO_ACT_LED);
		/** delay a bit to allow us see the blink! */
		for(loop=0;loop<0x200000;loop++);
	}
}
/*----------------------------------------------------------------------------*/