[OpenBIOS] PATH: Fix b(field) Fcode evaluation

[Blue Swirl]

On 5/25/09, Mark Cave-Ayland <mark.cave-ayland at siriusit.co.uk> wrote:
> Hi everyone,
>
>  This patch fixes the Fcode evaluation of b(field) which was implemented
> incorrectly. With this patch applied, corruption seen in several of the
> package words for Milax/Martux has now disappeared. Included below are the
> Fcode test cases I used (courtesy of Milax):

Thanks, applied (r499).