long long / long long

[John S. Dyson]

----- Original Message ----- 
From: "Joe Buck" <jbuck@synopsys.COM>
To: "Frank Klemm" <pfk@fuchs.offl.uni-jena.de>
Cc: "Jan Hubicka" <jh@suse.cz>; <gcc@gcc.gnu.org>
Sent: Sunday, September 09, 2001 11:51 PM
Subject: Re: long long / long long


> Frank Klemm writes:
> [ improved long long code sequences]
> > 
> > Interested? Or are 64 bit are uninteresting for benchmarks?
> 
> Well, the Linux kernel developers found that they couldn't let gcc
> do long long arithmetic because it did such a poor job, so they do
> it in assembly or in C on pairs of 32 bit values instead.  So at
> least some folks probably wouldn't mind seeing an improvement.
> 
When I was writing and rewriting parts of the FreeBSD code, I was
VERY careful to limit the 64bit long longs to exactly what was needed.

In fact, some consideration in data structure design was made to avoid
the use of 64bit offsets/addresses (for mapping files, etc).

John