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Add a snippet to show MicroBug at early boot

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Elliot Nunn 2020-11-22 10:17:14 +08:00
parent 10d99d74bb
commit f24a4e630a
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; A snippet that you can INCLUDE directly, to invoke MicroBug at early boot,
; when otherwise you would get a Sad Mac. Trick is to init the Event Queue.
; Expect 8 bytes of unfamiliar stuff on the stack and some clobbered regs.
; If you use this as a function, don't forget to RTS!
move.w #20,d0 ; number of events
dc.w $A06D ; _InitEvents
move.l $2BA,-(SP) ; save DSAlertTab
move.l #-1,$2BA ; because it needs to be nonzero
move.w #13,d0 ; as if we called _Debugger while it was unimp
dc.w $A9C9 ; _SysError
move.l (SP)+,$2BA ; restore DSAlertTab