Post by thread:[PICLIST] multibyte arithemetic

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? Wouter -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

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 <spam_OUTdwaynerTakeThisOuTplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 17 years of Engineering Innovation (1984 - 2001) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

(again with [PIC]:) > 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? > > Wouter -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics