用keil软件编写arm的定时器中断程序，为什么无法进入中断服务程序啊？

Question

#include<lpc214x.h>
#include<stdio.h>
#define led 1<<16

__irq void IRQ_TIMER0(void)
{
if((IO1SET&0x01)==0) IO1SET=1<<16;
else IO1CLR=1<<16;

T0IR=0x01;
VICVectAddr=0x00;

}

void vic_init()
{
VICIntSelect=0x00000000;
VICVectCntl0=0x02|0x04;
VICVectAddr0=(unsigned int)IRQ_TIMER0;
VICIntEnable=1<<0x04;
}

void time0_init()
{
T0TC=0;
T0PR=99;
T0MCR=0x03;
T0MCR=0x01;
T0MR0=120000;
T0TCR=0x03;
T0TCR=0x01;
}

int main()
{
PINSEL2=0x00;
IO1DIR=1<<16;
IO1SET=1<<16;

vic_init();
time0_init();

while(1);
}