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。小操作系统。

@  ____________________________________________________________________
@ 
@  Copyright (c) 2002, Andrew N. Sloss, Chris Wright and Dominic Symes
@  All rights reserved.
@  ____________________________________________________________________
@ 
@  NON-COMMERCIAL USE License
@  
@  Redistribution and use in source and binary forms, with or without 
@  modification, are permitted provided that the following conditions 
@  are met: 
@  
@  1. For NON-COMMERCIAL USE only.
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@  2. Redistributions of source code must retain the above copyright 
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@  4. All advertising materials mentioning features or use of this 
@     software must display the following acknowledgement:
@ 
@     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    : e7t
@ * History     :
@ *
@ * 21 December 2001 Andrew N. Sloss
@ * - started working on the handlers
@ *   
@ ****************************************************************************

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

     .text 
     .code 32
     .align 0
     .global eventsIRQHandler

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

     .extern eventTickService
     .extern eventButtonService
     .extern kernelScheduler

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

@ -- address of the IRQ controller for the Samsung KS32C50100. 

INTPND:
     .word 0x03ff4004    @ IRQ controller
     
@ -- 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, INTPND	 
     LDR     r0, [r0]                   @ get IRQ source		
     TST     r0, #0x0400
     BNE     eventTickVeneer            @ if timer interrupt
     TST     r0, #0x0001		
     BNE     eventButtonVeneer          @ if button interrupt
     LDMFD   r13!, {r0-r3, r12, pc}^    @ unknown event ignore

eventButtonVeneer:

     BL      eventButtonService
     LDMFD   r13!, {r0-r3, r12, pc}^    @ return to task

eventTickVeneer:

     BL      eventTickService
     B       kernelScheduler
     .end