Subject: Re: major revision of kernel 'evcnt' interfaces.
To: Anders Magnusson <ragge@ludd.luth.se>
From: Lennart Augustsson <lennart@augustsson.net>
List: tech-kern
Date: 06/04/2000 01:10:34
Anders Magnusson wrote:
> > On Sat, Jun 03, 2000 at 11:48:07PM +0200, Anders Magnusson wrote:
> >
> > > > struct evcnt {
> > > > u_int64_t ev_count; /* how many have occurred */
> > > /|\
> > > |
> > >
> > > This may be sub-optimal on many architectures. On vax, for example, it
> > > generates a bunch of extra insn's. If this is incremented often it
> > > would be not-so-good.
> >
> > Sounds like it's time to add a new pattern to vax.md!! :-)
> >
> Eh, new pattern? There are no 64-bit add/sub insn's on vax.
> (but there are move, shift and other...)
It's been a few years since I did any Vax assembly programming, but
surely it will only take one extra instruction? An add followed by an add with carry.
incl counter
adwc $0, counter+4
--
-- Lennart