wait_irq.mac

ARM入门的好帮手.包含了从简单到相对较复杂的程序.

;------------------------------------------------------------------------------
;-         ATMEL Microcontroller Software Support  -  ROUSSET  -
;------------------------------------------------------------------------------
; The software is delivered "AS IS" without warranty or condition of any
; kind, either express, implied or statutory. This includes without
; limitation any warranty or condition with respect to merchantability or
; fitness for any particular purpose, or against the infringements of
; intellectual property rights of others.
;------------------------------------------------------------------------------
;- File source          : wait_irq.mac
;- Object               : Assembler Wait Interrupt Handler Macro
;-
;- 1.0 01/04/00 JCZ     : Creation
;- 1.1 02/11/00 JPP     : Green Hills
;------------------------------------------------------------------------------

            AREA        wait_irq, CODE, READONLY, INTERWORK

            INCLUDE     ../../periph/timer_counter/tc.inc
           
;------------------------------------------------------------------------------
;- Function         : wait_irq
;- Treatments       : Wait Interrupt Handler
;- Operations       :
;-      - Write the IVR ( Protect Mode support )
;-      - Write the End of Interrupt Command Register
;-      - Read the TC Status Register to remove the wake-up interrupt 
;-      - Return
;------------------------------------------------------------------------------
            MACRO   
            wait_irq_asm_handler    $WaitDesc, $IrqHandler

            EXPORT  $IrqHandler
            IMPORT  $WaitDesc
$IrqHandler
;- Adjust and save LR_irq in IRQ stack
            stmfd       sp!, {r0}

;- Write in the IVR to support Protect Mode
;- No effect in Normal Mode
;- De-assert the NIRQ and clear the source in Protect Mode
            ldr         r0, =AIC_BASE
            str         r0, [r0, #AIC_IVR]
;- Mark the End of Interrupt on the AIC
            str         r0, [r0, #AIC_EOICR]

;- Read the Status Register of the used Timer Counter
            ldr         r0, =$WaitDesc
            ldr         r0, [r0]        ; get the Timer Counter Descriptor Address
            ldr         r0, [r0]        ; get the Timer Counter Channel Base Address
            ldr         r0, [r0, #TC_SR]
            
;- Adjust and save LR_irq in IRQ stack
            ldmia       sp!, {r0}

;- Adjust LR_irq and return 
            subs        pc, r14, #4

            MEND

            END