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From: augustss@chalmers.UUCP (Lennart Augustsson)
Newsgroups: net.lang.c
Subject: Re:  Two Birds with One Stone
Message-ID: <412@chalmers.UUCP>
Date: Sun, 22-Dec-85 22:19:56 EST
Article-I.D.: chalmers.412
Posted: Sun Dec 22 22:19:56 1985
Date-Received: Wed, 25-Dec-85 03:43:04 EST
References: <874@dataioDataio.UUCP> <864@kuling.UUCP>
Reply-To: augustss@chalmers.UUCP (Lennart Augustsson)
Organization: Dept. of CS, Chalmers, Sweden
Lines: 20

In article <864@kuling.UUCP> thomas@kuling.UUCP (Thomas H{meenaho) writes:
>However most useable processors provide arithmetic shifts which will give
>the right result even if it is a signed divide.

Replacing a divide with a signed shift doesn't solve the problem.  Consider
the following:
    decimal                             binary
    -1 / 2  = 0                         11111111 / 10 = 00000000
    -1 >> 1 = -1                        11111111 >> 1 = 11111111

Most machines behave like this when dividing, i.e. they divide the absolute
value of the operands and then sets the correct sign.  There are machines
(e.g. NS 32000) which provide a divide instruction with the other behaviour.

-- 
Any resemblance of the opinions above to real opinions, living or dead,
is purely coincidential.
	Lennart Augustsson
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