problem wiyh external inturrupt while debug session.

I wrote the program using external inturrupt0(p0.16). The program is executed but iam doing in the debug session it not going to IRQ_Handler.Tell me where iam doing the mistake.
my program is

#include <LPC214X.H>
#include <stdio.h>

void init_Eint1(void);
__irq void IRQ_Handler(void);
int main(void)
{ PINSEL0=0X00000000; IODIR0=0X00000001;
init_Eint1();

}

__irq void IRQ_Handler(void) //irq subroutine
{

EXTINT=0X00000001; //initialize the EINT0 if(EXTINT==0) { IOSET0=0X00000001; } else { IOCLR0=0X00000001; } VICVectAddr=0x00000000;
}

void init_Eint1(void)
{

EXTINT=0X00000001; PINSEL1=0X00000001; IOCLR0=0X00000001; EXTMODE=0X00000010; //edge sensitive mode EXTPOLAR=0X0000000; //falling edge VICIntEnable=0x00004000; VICVectAddr0=(unsigned long) IRQ_Handler; VICVectCntl0=0x0000002E;
}