From mboxrd@z Thu Jan  1 00:00:00 1970
From: dewar@gnat.com (Robert Dewar)
To: geoffk@cygnus.com, kenner@vlsi1.ultra.nyu.edu
Cc: gcc@gcc.gnu.org
Subject: Re: Pathalogical divides
Date: Mon, 25 Sep 2000 02:35:00 -0000
Message-id: <20000925060704.18ACD34DB0@nile.gnat.com>
X-SW-Source: 2000-09/msg00590.html

<<Yes.  C interpreters are permitted to do anything they like when
signed integer arithmetic overflows, including producing a signal.
>>

Actually while I think that is a valid interpretation of K&R rules,
it is VERY difficult to read the ANSI standard this way, check out
the exact wording, which seems to imply that the result is implementation
defined within certain limits, but I cannot read it to allow a signal.

By the way, the most efficient way of computing a%b to avoid
this problem is a%(abs b) being careful NOT to check for overflow
on the abs operation (not that one is likely to do so in C anyway :-)