From: elf AT netcom DOT com (Marc Singer)
Message-Id: <199605181836.LAA03196@netcom9.netcom.com>
Subject: Re: 64-bit integers
To: hinks AT netspace DOT net DOT au (Adam Hinkley)
Date: Sat, 18 May 1996 11:31:39 -0700 (PDT)
In-Reply-To: <199605150652.QAA01734@tornado.netspace.net.au> from "Adam Hinkley" at May 15, 96 04:58:07 pm
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Sender: elf AT netcom DOT com

> 
> Hello
> 
> Regarding the post...
> 
> > How portable are GNU long long ints?
> 
> Anyone know where I could get the source code for doing 64-bit integer 
> arithmetic - the long longs?  Or anyone have it and could mail it to me?
> 
> I need to be able to do both signed and unsigned 64-bit integer 
> arithmetic on a compiler that doesn't support it.  The fix is to use two 
> 32-bit integers (which I presume is what GNU does).  My attempts at doing 
> this have failed, but if I could find some source code for doing it...
> 

I have tried to create portable 64 bit integer arithmetic, but I've
found that C does not provide appropriate operators for capturing the
overflow results for 32bitx32bit multiplies and divides.  I've
considered building up very long integer support by using 1/2 word (16
bit) pieces, but this project was tabled when I found another
workaround.  I'm not sure there is any way to do this efficiently in C
without inline assembly code.

Marc Singer