irq_handler.s

ARM嵌入式系统开发--软件设计与优化随书源代码。开发环境asm+c

@  ____________________________________________________________________
@ 
@  Copyright (c) 2002, Andrew N. Sloss, Chris Wright and Dominic Symes
@  All rights reserved.
@  ____________________________________________________________________
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@  1. For NON-COMMERCIAL USE only.
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@     software must display the following acknowledgement:
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@     This product includes software developed by Andrew N. Sloss,
@     Chris Wright and Dominic Symes. 
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@ ****************************************************************************
@ * Simple Little Operating System - SLOS
@ ****************************************************************************

@ ****************************************************************************
@ *
@ * Module      : handler.s
@ * Description : handles the irq events
@ * OS          : SLOS
@ * Platform    : Integrator/AP 940
@ * History     :
@ *
@ * 19th April 2002 Andrew N. Sloss
@ * - added support for Integrator 940
@ *
@ * 30th April 2002 Andrew N. Sloss
@ * - remove the button service routine
@ *   
@ ****************************************************************************

@ ****************************************************************************
@ * EXPORT
@ ****************************************************************************

     .text
     .global eventsIRQHandler

@ ****************************************************************************
@ * IMPORT
@ ****************************************************************************

     .extern eventsTickCM940IAPService
     .extern kernelScheduler

@ ****************************************************************************
@ * ROUTINES
@ ****************************************************************************

CMRegisterBase:
     .word   0x10000000
IRQ0_BASE:
     .word   0x14000000

     .equ TIMERINT2, 0x00000080
     .equ STATUS, 0x00000000

@ -- events_irq_handler ------------------------------------------------------
@
@ Description	: handles the IRQ interrupt and determines the source and then
@		  vectors to the correct interrupt rountine.
@

eventsIRQHandler:
     SUB     r14, r14, #4
     STMFD   r13!, {r0-r3, r12, r14}  @ save context	
     LDR     r0, IRQ0_BASE            @ Load Base address of Int Ctrl
     LDR     r0, [r0,#STATUS]         @ Read Interrupt status
     LDR     r1, =0x000001ff          @ load value to mask off upper bits
     AND     r0, r0, r1               @ mask off unused interrupts
     TST     r0, #TIMERINT2
     BNE     eventsTickCM940IAPVeneer
     LDMFD   r13!, {r0-r3, r12, pc}^  @ unknown event ignore

eventsTickCM940IAPVeneer:
     BL      eventsTickCM940IAPService   @ reset timer
     B       kernelScheduler
     .end