At 08:02 PM 5/18/01 +0200, wouter van ooijen & floortje hanneman wrote:
>A looked into the uChip application note for fixed point (multibyte)
>arithmetic. All code in there seems to ignore code page and register bank
>issues. In some cases, such as the famous 4-instruction sequence for a
>multibyte add or substract, this can be quite annoying. Are there any more
>realistic sources for such code, or is it customary to first copy all data
>so that it is all in one bank, and arrange the code so that is does not
>straddle multiple pages?

I suppose there is a problem if the RAM straddles 2 RAM pages, but you as
the programmer should have already caught that.  There is no problem with
the 4-instruction sequence for multi-byte add and subtract code crossing a
page boundary because there are no 'goto' instructions, merely skip
instructions which are not affected by page boundaries.

dwayne



Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax

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