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From: gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>)
Newsgroups: net.lang.c
Subject: Re: How to test for +/- INFINITY, etc. in C with IEEE
Message-ID: <712@brl-tgr.ARPA>
Date: Sun, 15-Dec-85 19:47:08 EST
Article-I.D.: brl-tgr.712
Posted: Sun Dec 15 19:47:08 1985
Date-Received: Tue, 17-Dec-85 07:25:44 EST
References: <993@turtlevax.UUCP> <8040@ucla-cs.ARPA>
Organization: Ballistic Research Lab
Lines: 11

>    short pi[4] = {0x4008,0x1234,etc,etc};
>    double x, y;
>    x = y * *(double *)pi

Beware!  The alignment applied to (short) data may not be
sufficiently stringent for (double) data, so the result of
the (double *) typecast (assuming the compiler allows it)
may not be suitable for the address of an operand for a
floating-point instruction.  We have machines like that..

You can overcome this problem by proper use of a union.