*------------------------------------------------------------------------------

*

*   Apple Macintosh Developer Technical Support

*

*   Sample Control Panel Device and INIT Combination

*

*   Program:    INIT - CDEV

*   File:       INIT.a  -   Asm Source

*

*   Copyright © 1990 Apple Computer, Inc.

*   All rights reserved.

*

*------------------------------------------------------------------------------

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;

;   void a_SystemTask()

;

;   This is the real patch to SystemTask(). It saves all registers that

;   shouldn't be tampered with, calls the C routine that does all the dirty

;   work, and restores the registers. It then pushes the address of the

;   real ROM SystemTask routine onto the stack and RTS, which is a neat

;   way to jump to that routine without messing up any registers.

;

;   "oldSystemTask" is filled in during INIT initialization by the routine

;   INITInstall.

;

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a_SystemTask    PROC    EXPORT

                IMPORT  c_SystemTask:CODE

                EXPORT  oldSystemTask

                movem.l D0-D7/A0-A5,-(sp)       ; Save our registers

                bsr     c_SystemTask            ; call the C routine

                movem.l (sp)+,D0-D7/A0-A5       ; restore the registers

                move.l  oldSystemTask,-(sp)     ; push addr. of orig. SystemTask

                rts                             ; RTS will just jump to it.

oldSystemTask   ds.l    1                       ; address of original SystemTask

                ENDP

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;

;   void a_SetA5Ref(A5Ref)

;

;       Simply takes the value passed in and saves it in "A5Storage". This

;       routine uses the C calling convetion, so it doesn't need to pull

;       and parameters off of the stack.

;

;   long a_GetA5Ref()

;

;       Returns the value stored in "A5Storage". This routine uses the C

;       callin convention, so the result is returned in D0.

;

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a_SetA5Ref      PROC    EXPORT

                EXPORT  a_GetA5Ref

                lea     A5Storage,A0            ; get address of storage

                move.l  4(sp),(A0)              ; move value to save into it

                rts                             ; return to caller

a_GetA5Ref

                move.l  A5Storage,D0            ; get result into D0

                rts                             ; return to caller

A5Storage       ds.l    1                       ; storage for A5 reference

                ENDP

                END