From owner-cvs-all  Wed Mar 20 17: 9:20 2002
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Date: Thu, 21 Mar 2002 12:09:23 +1100 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: "David O'Brien" <obrien@FreeBSD.org>
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Subject: Re: cvs commit: src/sbin/camcontrol camcontrol.c modeedit.c
 src/sbin/dumpfs dumpfs.c src/sbin/fsck_ffs dir.c fsutil.c inode.c pass1.c
 pass1b.c pass2.c pass4.c pass5.c preen.c setup.c
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On Wed, 20 Mar 2002, David O'Brien wrote:

> On Thu, Mar 21, 2002 at 09:03:54AM +1100, Bruce Evans wrote:
> > >   Log:
> > >   Remove 'register' keyword.
> > >   It does not help modern compilers, and some may take some hit from it.
> > >   (I also found several functions that listed *every* of its 10 local vars with
> > >    "register" -- just how many free registers do people think machines have?)
> >
> > Most machines designed after 1978 (8?) other than i386's have many.
> > Programmers declared almost all local variables as register to encourage the
> > compiler to keep as many as possible in registers.
>
> The key word I used was _FREE_, as in not being used for temparies, and
> other operations. :-)

This is not very different for a compiler that does stupid register
allocation.  Most operations only take 2 or 3 registers, so there are
usually 13 or 14 free on machines with 16 general registers.

Bruce


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