> WAS:
> > intr_off macro
> >   if fam_16
> >          bcf     intcon, gie
> >     endif
> >   if fam_17
> >          bsf     cpusta, glintd
> >     endif
> >          endm
>
>
> BETTER?:
>  intr_off macro
>    if fam_16
>  foo:
>           bcf     intcon, gie
>           btfsc   intcon, gie
>           goto    foo
>      endif
>    if fam_17
>  bar:
>           bsf     cpusta, glintd
>           btfss   cpusta, glintd
>           goto    bar
>      endif
>           endm

I was the one who posted the original macro.  Is this true!?  Can an
interrupt really happen immediately after the instruction that disables
interrupts?  This seems hard to believe.  I've never seen any mention of
this issue in the Microchip docs, and yes, I DO read the manual.  If this
were really true I would expect at least a one of those gray boxes
mentioning this issue.

I just re-read the interrupt section of the 16F87x and 17C7xx data sheets
and didn't see any mention of this issue.  Both mentioned a possible
interrupt latency of up to 2 or 3 cycles from external conditions, but I am
assuming the interrupt still can't take place if they are globally disabled.
Someone from Microchip please confirm/deny this?

By the way, if you are going to put labels in a macro like this, you really
should declare them LOCAL.


*****************************************************************
Olin Lathrop, embedded systems consultant in Devens Massachusetts
(978) 772-3129, olin@cognivis.com, http://www.cognivis.com

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