the problem of the PIO interrupts

Hello,everybody!

My program can't get into the interrupt fuction. the code like is the following.is there any questions? and I can't use a main() but alt_main(),if I use main() the nisoII IDE show me many errors;I use a CPU /e.

CODE:

# include "system.h"# include "altera_avalon_pio_regs.h"# include "alt_types.h"# include "sys/alt_irq.h"

volatile int edge_capture;

void Sirq(void * context,alt_u32 id)

{

IOWR_ALTERA_AVALON_PIO_EDGE_CAP(PIO_SWITCH_BASE, 0);

IOWR_ALTERA_AVALON_PIO_DATA(PIO_LED1_BASE,IORD_ALTERA_AVALON_PIO_DATA(PIO_SWITCH

_BASE));

}

int main (void) __attribute__ ((weak, alias ("alt_main")));

int alt_main (void)

{

alt_irq_register(PIO_SWITCH_IRQ,(void *)0,Sirq);

IOWR_ALTERA_AVALON_PIO_EDGE_CAP(PIO_SWITCH_BASE, 0);

IOWR_ALTERA_AVALON_PIO_DIRECTION(PIO_SWITCH_BASE, 0);

IOWR_ALTERA_AVALON_PIO_IRQ_MASK(PIO_SWITCH_BASE, 0xff);

while (1)

{

}

return 0;

}

Thanks~!