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From: Jack Johnson <knapjack@gmail.com>
To: 9fans <9fans@cse.psu.edu>
Subject: [9fans] More Microsoft bashing
Date: Thu, 15 Dec 2005 20:04:02 -0800	[thread overview]
Message-ID: <6e35c0620512152004n37c06ff5wd250424db50d874d@mail.gmail.com> (raw)

Not really, but all the talk about Singularity got me poking around
and I came across this:

------

How are the functions DIV and MOD defined?

The following answers are given by the Internal Working Document on
the Common Language Infrastructure (CLI).

result = value1 DIV value2 satisfies the following conditions:
|result| = |value1| / |value2|, and
sign(result) = +, if sign(value1) = sign(value2)
sign(result) = - , if sign(value1) # sign(value2)

result  = value1 MOD value2 satisfies the following conditions:
result = value1 - value2 * (value1 DIV value2), and
0 <= |result| < |value2|, and
sign(result) = sign(value1)

Please note that this definition of DIV and MOD differs from the
definition given in [M. Reiser, N. Wirth. Programming in Oberon. p.
36]:
x  = (x DIV y) * y + (x MOD y), and
0 <= (x MOD y) < y

( from http://www.bluebottle.ethz.ch/oberon.net/faq.html#ad_DivMod )

------

I kind of collect random, older computer science texts, so I cracked
open The Nature of Computation by Pohl and Shaw, which yields:

  "x MOD y = x - (x ÷ y) * y, where ÷ indicates integer division (i.e.
fractions are disregarded; equivalently, the result of the division is
truncated)."

So, what *is* -5 MOD 3?

-Jack


             reply	other threads:[~2005-12-16  4:04 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-16  4:04 Jack Johnson [this message]
2005-12-16  4:51 ` Dan Cross
2005-12-16  5:02   ` Dan Cross
2005-12-16  5:33     ` erik quanstrom
2005-12-16  5:38       ` Bruce Ellis
2005-12-16 10:46         ` Charles Forsyth
2005-12-16 13:13       ` Dan Cross
2005-12-16  4:53 ` erik quanstrom
2005-12-16  5:08   ` Dan Cross
2005-12-16  5:19     ` Brian L. Stuart
2005-12-16  5:27     ` Bruce Ellis
2005-12-16 14:19     ` Brantley Coile
2005-12-16 15:13       ` Bruce Ellis
2005-12-16 15:29         ` Russ Cox
2005-12-16 16:00           ` Bruce Ellis
2005-12-17  0:26             ` Jack Johnson
2005-12-17  3:59               ` Bruce Ellis
2005-12-16 15:33         ` Brantley Coile
2005-12-16 10:47   ` John Stalker
2005-12-16 14:25     ` Brantley Coile
2005-12-16 14:51       ` Gorka guardiola
2005-12-16 22:28     ` Victor Nazarov
2005-12-17 11:09 ` David Leimbach
2005-12-17 11:24   ` David Leimbach

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