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From: tps@sdchem.UUCP (Tom Stockfisch)
Newsgroups: net.lang.c
Subject: Re: Shift by negative quantity
Message-ID: <252@sdchema.sdchem.UUCP>
Date: Tue, 8-Jul-86 12:23:12 EDT
Article-I.D.: sdchema.252
Posted: Tue Jul  8 12:23:12 1986
Date-Received: Wed, 9-Jul-86 03:28:29 EDT
References: <894@bu-cs.UUCP>
Reply-To: tps@sdchema.UUCP (Tom Stockfisch)
Organization: Chemistry Dept, UC San Diego
Lines: 20

In article <894@bu-cs.UUCP> bzs@bu-cs.UUCP (Barry Shein) writes:
>Question: Is shifting by a negative quantity defined (that is,
>probably means the other shift.) I could find no mention in K&R.
>...

Looking up "shift operators" in the index of K&R, I am referred to p. 189:

	"The result [of a shift operator] is undefined if the right operand
	is negative, or greater than or equal to the length of the object
	in bits."

I'm sure its done this way so that the operation is closer to every machine's
instruction set and isn't a higher-level operation with additional checks
or conversions.

>P.S. Is this one of those questions that gets asked every 2 months?

I haven't seen it before.

--Tom Stockfisch, UCSD Chemistry