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From: bchen@nntp-server.caltech.edu (Bing-Qing Chen)
Newsgroups: comp.sys.next
Subject: Re: cc compiler problems
Message-ID: <1991Apr8.170642.3606@nntp-server.caltech.edu>
Date: 8 Apr 91 17:06:42 GMT
References: <1991Apr7.170437.24517@msuinfo.cl.msu.edu>
Distribution: na
Organization: California Institute of Technology, Pasadena
Lines: 21

In article <1991Apr7.170437.24517@msuinfo.cl.msu.edu> chouw@galaxy.cps.msu.edu (Wen Hwa Chou) writes:
>There is nothing fancy in the included small C programs.  When compiled as
>"cc -o starnge strange.c" everything is OK.  But when I tried it as
>"cc -O -o strange strange.c"  than the Slab is gone - I mean totally gone.
>I would not even respond to the cmd-cmd-~ sequence.  The only way to recover
>it is by UNPLUG/PLUG!!!
>
>I don't think this can be called as a FEATURE or ANSI Standard.  So, what is
>the problem and where is the fix?  Anybody has any idea?
>
> ... program deleted ...
This appeared to be the same program I posted several months ago.
Apparently, there is a floating point operation bug either in the OS or in 
the 68040. I believe that somebody at NeXT tried the program under 2.1 OS 
and claimed that it didn't crash the system under 2.1. Hopefully, this
is a OS bug instead of 68040 bug. This really has nothing to do with the
compiler. With the -O flag, the compiler will generate a very tight loop
using register divide instruction fdivx which caused the crash.

Bing Chen
bchen@pooh.caltech.edu