Subject: Re: problems with ahc vs. format command
To: Todd Vierling <firstname.lastname@example.org>
From: Manuel Bouyer <email@example.com>
Date: 06/12/2001 18:53:53
On Tue, Jun 12, 2001 at 12:45:02PM -0400, Todd Vierling wrote:
> On Tue, 12 Jun 2001, Manuel Bouyer wrote:
> : > callout_reset(&scb->xs->xs_callout,
> : > (newtimeout > 3*1000*1000 ?
> : > ((newtimeout / 1000 + 1) * hz) : (newtimeout * hz) / 1000),
> : > ahc_timeout, scb);
> : The question is whenever the test is really less expansive than the
> : 64bit computation. I think on some platforms it may be more expensive.
> Only on LP64 platforms, really (sparc64, alpha) -- and those could be
> conditionally compiled to use solely 64-bit arithmetic.
> The flip side is that a 64-bit "/ 1000" is a *lot* slower than its 32-bit
> equivalent on ILP32 platforms, particularly those for which even integer
> divide is a library function (sparc v7).
Hum, yes I was only thinking about multiplication, no divide.
Do we have a macro that could be tested to know whenever we're on a 32 or
64bit platform ?
Manuel Bouyer, LIP6, Universite Paris VI. Manuel.Bouyer@lip6.fr