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Path: utzoo!linus!decvax!harpo!eagle!allegra!alan
From: alan@allegra.UUCP (Alan S. Driscoll)
Newsgroups: net.lang.c
Subject: Beware: Hackers
Message-ID: <2189@allegra.UUCP>
Date: Sun, 8-Jan-84 14:38:19 EST
Article-I.D.: allegra.2189
Posted: Sun Jan  8 14:38:19 1984
Date-Received: Mon, 9-Jan-84 01:55:20 EST
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 28


From Roger Ferrel:

	What we see here with the:

		inttype *= 0.5;
			vs
		inttype = inttype * 0.5;

	is a weakness of most C compilers. It seems none of them handles
	float operations very well when there are mixed types.  Of course
	the above is a poor example since normally more efficent code would
	be generated by using:

	inttype >>= 1;  /* how is this for getting off the subject? */

From the C Reference Manual:

	The value of E1>>E2 is E1 right-shifted E2 bits.  The right shift
	is guaranteed to be logical (0-fill) if E1 is unsigned; otherwise
	it may be arithmetic (fill by a copy of the sign bit).

If the shift is logical, then negative values of "inttype" will give you
interesting results.


	Alan S. Driscoll
	AT&T Bell Laboratories