Tony Nixon <Tony.Nixon@ENG.MONASH.EDU.AU> wrote:
> Test if a value is in a certain range
>
> W = value
>
> addlw 255 - Hi
> addlw (Hi - Lo) + 1
>
> Carry is set if W is in range Lo - Hi

That can't possibly work!  There aren't enough instructions!  And I refuse
to try it out to see if it works, since I know I'm right!

Sorry, I couldn't resist.  That's the sort of feedback I got when I posted
this method here years ago.  I normally use a macro for this, so that
I don't have to remember the details.

On the 12-bit core, there is no addlw instruction, so doing the equivalent
requires a temporary register and three more instructions:

        movwf   temp
        movlw   255-Hi
        addwf   temp
        movlw   (hi-lo)+1
        addwf   temp,w

Cheers,
Eric