Re: [Flashforth-devel] Bug report: Can't write beyond $a300

[Mikael N. <mik...@pp...>]

Thanks Pablo for spotting that.

I hope unsigned compare is used in all other places that does the memory 
mapping.

I will include this fix.

BR Mikael

On 06/17/2013 08:52 PM, Pablo M. Muñoz wrote:
> I think I have found a (small) bug.
>
> In FF 3.8 (original) compiled for a 18F2620, trying to write beyond 
> $a300 gives an "AD?" error.
>
> I have found the problem here:
>
> ISTORECHK:
>         movlw    HIGH dpcode ;(dp_user_dictionary>>8) ;
>         subwf    Srw, W, A
>         btfsc   STATUS, N, A
>         bra     ISTORERR
>         return
>
> The instruction subwf gives a signed result, and sets N if (Srw) - W > $7f
>
> This can be solved with an unsigned compare:
>
> ISTORECHK:
>         movlw    HIGH dpcode ;(dp_user_dictionary>>8) ;
>         cpfslt  Srw, A
>         return
>         bra     ISTORERR
>
> With this change, writes work OK from $2300 to $ebff.
>
> I made this change in order to put the help system at the end of the 
> flash space.
>
>