[comp.sys.apple] GS BRK instructions

dlyons@Apple.COM (David A. Lyons) (12/07/89)

In article <1989Dec1.182211.26517@ux1.cso.uiuc.edu> jb10320@uxa.cso.uiuc.edu (Jawaid Bazyar) writes:
>In article <8222.infoapple.net@pro-generic> ericmcg@pro-generic.cts.com (Eric Mcgillicuddy) writes:
>>In-Reply-To: message from jb10320@uxa.cso.uiuc.edu
>>
>>It seems to me the debugger replaces the instruction with a BRK instruction
>>and then traps the interupt whern it hits it. If the interupt were disabled
>>would this affect the BRK? I would like to know since I am working with
>>interupts on my own project and am having a rough time of it.

BRK instructions can't be disabled (even though they get dispatched through
the same vector as interrupt requests (IRQs)).

>As far as I've noticed, the debugger breakpoints only
>function during a step or trace operation.  I manually use the BRK breakpoint
>method when I need to run my code at full-speed.

The debugger provides the option of setting real breakpoints that work
when executing real-time code.  It's in the manual & (at least in some
versions) in the BP online help.
-- 

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