.section .startup,"ax"
         .code 32
         .align 0

    b     _start                        /* reset - _start           */
    ldr   pc, _undf                     /* undefined - _undf        */
    ldr   pc, _swi                      /* SWI - _swi               */
    ldr   pc, _pabt                     /* program abort - _pabt    */
    ldr   pc, _dabt                     /* data abort - _dabt       */
    nop                                 /* reserved                 */
    ldr   pc, _irq              /* IRQ - read the VIC       */
    ldr   pc, _fiq                      /* FIQ - _fiq               */

_undf:  .word 0x4030CE24 /* undefined               */
_swi:   .word 0x4030CE28 /* SWI                     */
_pabt:  .word 0x4030CE2C /* program abort           */
_dabt:  .word 0x4030CE30 /* data abort              */
_irq:  .word 0x4030CE38
_fiq:   .word 0x4030CE3C /* FIQ                     */

#define E_IRQ                   (*(REG32 (0x4030CE38)))
....
/* Setup interrupt handler */
E_IRQ = ( long ) vIRQHandler;

/* Set V=0 in CP15 SCTRL register - for VBAR to point to vector */
mrc    p15, 0, r0, c1, c0, 0    @ Read CP15 SCTRL Register
bic    r0, #(1 << 13)       @ V = 0
mcr    p15, 0, r0, c1, c0, 0    @ Write CP15 SCTRL Register

/* Set vector address in CP15 VBAR register */
ldr     r0, =_vector_table
mcr     p15, 0, r0, c12, c0, 0  @Set VBAR

bl      main

.section .startup,"ax"
         .code 32
         .align 0
_vector_table:  b     _start    /* reset - _start       */
        ldr   pc, _undf         /* undefined - _undf        */
        ldr   pc, _swi          /* SWI - _swi               */
        ldr   pc, _pabt     /* program abort - _pabt    */
        ldr   pc, _dabt     /* data abort - _dabt       */
        nop                 /* reserved             */
        ldr   pc, _irq      /* IRQ - read the VIC       */
        ldr   pc, _fiq      /* FIQ - _fiq               */