[Oberon] PO2013 - CopyBlock

Joerg joerg.straube at iaeth.ch
Thu Jul 9 11:24:30 CEST 2020

CopyBlock has to take care of overlaps and in its general form has to mask, copy and shift bits.To add a special case for vertical scrolling (sx = dx) can make sense as you only have to mask and copy and leave out the shifts. (as n=0)

What is special with horizontal scrolling? Where do you see the optimization compared to the original CopyBlock?

Von: Oberon <oberon-bounces at lists.inf.ethz.ch> im Auftrag von Tomas Kral <thomas.kral at email.cz>
Gesendet: Donnerstag, Juli 9, 2020 10:02
An: oberon at lists.inf.ethz.ch
Betreff: Re: [Oberon] PO2013 - CopyBlock > 1) I expected something like „IF dy = sy THEN“
> 2) your code overwrites the horizontal line with length „w“ starting
> at (dx, dy-1)


That is a current penalty for the code case „IF dy = sy THEN“
missing. Calling proc relies on unused bottom line beneath,
which could be cached w/ COPY, but seems overkill.

Tomas Kral <thomas.kral at email.cz>
Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
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