中断处理函数

.macro vector_stub, name, mode, correction=0
.align 5


vector_\name:
.if \correction
sub lr, lr, #\correction
.endif


@
@ Save r0, lr_ (parent PC) and spsr_
@ (parent CPSR)
@
stmia sp, {r0, lr} @ save r0, lr
mrs lr, spsr
str lr, [sp, #8] @ save spsr


@
@ Prepare for SVC32 mode.  IRQs remain disabled.
@
mrs r0, cpsr
eor r0, r0, #(\mode ^ SVC_MODE | PSR_ISETSTATE)
msr spsr_cxsf, r0


@
@ the branch table must immediately follow this code
@
and lr, lr, #0x0f
 THUMB( adr r0, 1f )
 THUMB( ldr lr, [r0, lr, lsl #2] )
mov r0, sp
 ARM( ldr lr, [pc, lr, lsl #2] )
movs pc, lr @ branch to handler in SVC mode

ENDPROC(vector_\name)

/*
 * Interrupt dispatcher
 */
vector_stub irq, IRQ_MODE, 4


.long __irq_usr @  0  (USR_26 / USR_32)
.long __irq_invalid @  1  (FIQ_26 / FIQ_32)
.long __irq_invalid @  2  (IRQ_26 / IRQ_32)
.long __irq_svc @  3  (SVC_26 / SVC_32)
.long __irq_invalid @  4
.long __irq_invalid @  5
.long __irq_invalid @  6
.long __irq_invalid @  7
.long __irq_invalid @  8
.long __irq_invalid @  9
.long __irq_invalid @  a
.long __irq_invalid @  b
.long __irq_invalid @  c
.long __irq_invalid @  d
.long __irq_invalid @  e
.long __irq_invalid @  f