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From: Peter Schotman <schotman@tip.nl>
Subject: Question: special rounding
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Date: Thu, 5 Dec 1996 18:34:24 GMT
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Hi,

I developped some functions to carry out interval arithmetic in common
lisp (Franz inc.'s Allegro CL 3.0 for Windows95).
E.g. [a,b] + [c,d] = [a+c, b+d], etc. 
However I would like to calculate safe bounds (outward rounding), that
is rounding a+c downward and b+d upward. In C you can use some
(assambler) functions to change the last bit, which depends of course on
the precision chosen (e.g. doubble) and is also machine dependant. How
can I do something like this in lisp?

Any ideas?



Thanks in advance,

Peter Schotman
