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From: chris@mimsy.UUCP
Newsgroups: comp.unix.wizards,comp.lang.c
Subject: Re: Incorrect subtraction in C program
Message-ID: <6879@mimsy.UUCP>
Date: Tue, 2-Jun-87 02:29:51 EDT
Article-I.D.: mimsy.6879
Posted: Tue Jun  2 02:29:51 1987
Date-Received: Thu, 4-Jun-87 01:20:49 EDT
References: <1573@uwmacc.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 17
Keywords: vax, C, 4.3BSD
Xref: utgpu comp.unix.wizards:2342 comp.lang.c:2199
Summary: emulate.s bug

In article <1573@uwmacc.UUCP> jwp@uwmacc.UUCP (Jeffrey W Percival) writes:
>The problem is that when I subtract a tiny number from 1,
>I get 1 (the right answer) on a VAX 780 running 4.3BSD, but
>I get 0 (the wrong answer) on a MicroVAX running 4.3BSD.  Here's
>the program:

[the important line:]
>    fprintf(stdout, "a=%f, b=%f, c=%f, d=%f, e=%f\n", a, b, c, d, e);

There is a bug in the emulation code in /sys/vax/emulate.s.  Try

	main(){printf("%.0f\n", 0.9);exit(0);}

I have not seen a fix on comp.bugs.4bsd.ucb-fixes.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
Domain:	chris@mimsy.umd.edu	Path:	seismo!mimsy!chris