u-boot1.1.6启动过程分析-异常向量表

.globl _start
_start:	b       reset                        
	ldr	pc, _undefined_instruction           
	ldr	pc, _software_interrupt              /* 0x00000008软中断异常 */
	ldr	pc, _prefetch_abort                  /* 0x0000000c预取异常 */
	ldr	pc, _data_abort                      /* 0x00000010数据异常 */
	ldr	pc, _not_used                        /* 0x00000014 */
	ldr	pc, _irq                             /* 0x00000018外部中断异常 */
	ldr	pc, _fiq                             /* 0x0000001c快速中断异常 */

_undefined_instruction:	 undefined_instruction
_software_interrupt:	.word software_interrupt
_prefetch_abort:	.word prefetch_abort
_data_abort:		.word data_abort
_not_used:		.word not_used
_irq:			.word irq
_fiq:			.word fiq



	.align  5
undefined_instruction:
	get_bad_stack
	bad_save_user_regs
	bl 	do_undefined_instruction

	.align	5
software_interrupt:
	get_bad_stack
	bad_save_user_regs
	bl 	do_software_interrupt

	.align	5
prefetch_abort:
	get_bad_stack
	bad_save_user_regs
	bl 	do_prefetch_abort

	.align	5
data_abort:
	get_bad_stack
	bad_save_user_regs
	bl 	do_data_abort

	.align	5
not_used:
	get_bad_stack
	bad_save_user_regs
	bl 	do_not_used
	
	.align	5
irq:
/* add by www.100ask.net to use IRQ for USB and DMA */
	sub	lr, lr, #4			        @ the return address
	ldr	sp, IRQ_STACK_START	        @ the stack for irq
	stmdb	sp!, 	{ r0-r12,lr }	@ save registers
	
	ldr	lr,	=int_return		        @ set the return addr
	ldr	pc, =IRQ_Handle		        @ call the isr
int_return:
	ldmia	sp!, 	{ r0-r12,pc }^	@ return from interrupt

	.align	5
fiq:
	get_fiq_stack
	/* someone ought to write a more effiction fiq_save_user_regs */
	irq_save_user_regs
	bl 	do_fiq
	irq_restore_user_regs