EINT0CON0  External Interrupt 0(Group0) Configuration Register 0 
设置 外部中断的触发方式（高电平等）
EINT0PEND  External Interrupt 0(Group0) Pending Register  屏蔽前的中断（谁中断，相应位置1）
EINT0MASK  External Interrupt 0(Group0) Mask Register   屏蔽（屏蔽谁，相应位置1）
以上两个是管脚级别（GPIO）的pending和mask寄存器；
下边是中断控制器的pending和mask寄存器
VIC0INTENABLE  Interrupt Enable Register (VIC0)   //相当于mask寄存器
VIC0IRQSTATUS  IRQ Status Register (VIC0)  相当与pending寄存器

程序代码
main.c 
//led
#define GPKCON  (*(volatile unsigned int *)0x7f008800)
#define GPKDAT  (*(volatile unsigned int *)0x7f008808)

//button
#define GPNCON (*(volatile unsigned int *)0x7F008830)
#define GPNDAT  (*(volatile unsigned int *)0x7F008834)

//beep
#define GPFCON  (*(volatile unsigned int *)0x7F0080A0)
#define GPFDAT  (*(volatile unsigned int *)0x7F0080A4)
//
#define EINT0CON0  (*(volatile unsigned int *)0x7F008900)
#define EINT0MASK  (*(volatile unsigned int *)0x7F008920)

#define EINT0PEND  (*(volatile unsigned int *)0x7F008924)

//////interrupt contruller
#define VIC0IRQSTATUS  (*(volatile unsigned int *)0x71200000)
#define VIC0INTENABLE  (*(volatile unsigned int *)0x71200010)

#define VIC0RAWINTR  (*(volatile unsigned int *)0x71200008)
int led_init(void)
{
 //GPK4//
 GPKCON |= 1<<16;
 GPKCON &= ~(1<<17 | 1<<18 | 1<<19);
 //GPK5//
 GPKCON |= 1<<20;
 GPKCON &= ~(1<<21 | 1<<22 | 1<<23);
 //GPK6//
 GPKCON |= 1<<24;
 GPKCON &= ~(1<<25 | 1<<26 | 1<<27 );
 //GPK7//
 GPKCON |= 1<<28;
 GPKCON &= ~(1<<29 | 1<<30 | (unsigned)1<<31);
 return 0;
}
void led_value(int value)
{
 GPKDAT = ~value << 4;
}
void led_on(void)
{
 GPKDAT =0;
}
void led_off(void)
{
 GPKDAT = 0xf0;
}
void delay(void)
{
 int i = 0;
 for(i = 0; i <500000; i++);
}
void led_blink(void)
{
 led_on();
 delay();
 led_off();
 delay();
}
void beep_init(void)
{
 GPFCON |= 1<<28;
 GPFCON &= ~(1<<29);
}
void beep_on(void)
{
 GPFDAT |= 1<<14;
}
void beep_off(void)
{
 GPFDAT &= ~(1<<14);
}
void beep(void)
{
 beep_on();
 delay();
 beep_off();
 delay();
}
void do_irq()
{
 //at start, clear pending bit
 EINT0PEND = 1<<0;
 beep();
 /*
 void (*pf)(void);
 pf = vicoaddress;
 (*pf)();
 */
}
void irq_handler(void);

void test(void)
{
 GPFDAT |= 1<<14;
}
int mymain(void)
{
 int *p;
 int counter = 0;
 led_init();
 
 beep_init();
 //beep();
 //GPFDAT |= 1<<14;
 
 //GPNCON &= ~(1<<0 | 1<<1);
 //111111GPN0[1:0] interrupt
 GPNCON |= 1<<1;
 GPNCON &= ~(1<<0);
 
 //2222 EINT0CON1[2:0] 
 EINT0CON0 &= ~(1<<2);
 EINT0CON0 |= 1<<1;
 
 //33333 EINT0MASK[0]
 EINT0MASK &= ~(1<<0);
 //EINT0MASK |= 1<<0;
 //444444 VIC0INTENABLE
 VIC0INTENABLE |= 1<<0;
 //VIC0INTENABLE &= ~(1<<0);
 //555555
 //VIC0RAWINTR &= ~(1<<0);
 // arm core I_BIT :enable IRQ
 __asm
 {
  mov r0, #0x53
  msr CPSR_cxsf, r0  
 }
 p = (int *)0x18;
 *p = 0xe59ff000;
 p = (int *)0x20;
 *p = (int)irq_handler;
 
 /*
 VIC0VECADDR0 = beep1;
 VIC0VECADDR0 = beep2;
 */
 while(1)
 {
  if(VIC0IRQSTATUS  &(1<<0))
  {
   beep();
  }
  led_value(counter & 0x0f);
  counter++;
  delay();
  //if(GPNDAT & (1<<0))
  // led_on();
  //else
  // led_off();
 }
 return 0;
}

start.s文件

 AREA int, CODE, READONLY
 import mymain
 
 ENTRY 
 ;sp_irq mode 
 mov r0, #0xd2
 msr cpsr_cxsf,r0
 ldr sp, =0x50200000
 
 ;sp_svc mode 
 mov r0, #0xd3
 msr cpsr_cxsf, r0
 ldr sp, =0x50100000
 
 b mymain
 import do_irq
 export irq_handler 
irq_handler
 ;push rets to stack
 stmfd sp!,{r0-r12,lr}   //r0-r12 和lr压栈保护；
 
 ;handler
 bl do_irq
 ;pop stack to regs
 ldmfd sp!, {r0-r12,lr}
 subs pc, lr,#4
  
 END