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Re: [Qemu-devel] [PATCH v2] Use ffs in favor of ffsll
From: |
Stuart Brady |
Subject: |
Re: [Qemu-devel] [PATCH v2] Use ffs in favor of ffsll |
Date: |
Thu, 2 Jul 2009 00:02:16 +0100 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
On Wed, Jul 01, 2009 at 01:58:02PM -0700, Nathan Froyd wrote:
> On Wed, Jul 01, 2009 at 10:55:02PM +0200, Jan Kiszka wrote:
> > - for (i = 0; i < ARRAY_SIZE(env->interrupt_bitmap); i++) {
> > - bit = ffsll(env->interrupt_bitmap[i]);
> > + for (i = 0; i < sizeof(env->interrupt_bitmap) / sizeof(int); i++) {
> > + /* Note: This assumes little endian host, which is true in KVM
> > mode.
> > + In TCG mode it must be zero anyway. */
> > + bit = ffs(((int *)env->interrupt_bitmap)[i]);
>
> ISTR that some PPC hosts support KVM...
FWIW, I notice we currently have a qemu_fls() defined in cutils.c, which
uses the clz32() defined in host-utils.h.
qemu_ffsll() could be implemented fairly easily in terms of ctz64(),
although note that ffsll(n) == (ctz64(n) + 1) % 65.
Cheers,
--
Stuart Brady
- [Qemu-devel] [PATCH] Use ffs in favor of ffsll, Jan Kiszka, 2009/07/01
- [Qemu-devel] Re: [PATCH] Use ffs in favor of ffsll, Blue Swirl, 2009/07/01
- [Qemu-devel] Re: [PATCH] Use ffs in favor of ffsll, Jan Kiszka, 2009/07/01
- [Qemu-devel] [PATCH v2] Use ffs in favor of ffsll, Jan Kiszka, 2009/07/01
- Re: [Qemu-devel] [PATCH v2] Use ffs in favor of ffsll, Nathan Froyd, 2009/07/01
- [Qemu-devel] Re: [PATCH v2] Use ffs in favor of ffsll, Jan Kiszka, 2009/07/01
- Re: [Qemu-devel] [PATCH v2] Use ffs in favor of ffsll,
Stuart Brady <=
- [Qemu-devel] [PATCH] Use ctz64 in favor of ffsll, Jan Kiszka, 2009/07/02
- [Qemu-devel] [PATCH v2] Use ctz64 in favor of ffsll, Jan Kiszka, 2009/07/02
- Re: [Qemu-devel] [PATCH v2] Use ctz64 in favor of ffsll, Paul Brook, 2009/07/03
- Re: [Qemu-devel] [PATCH v2] Use ctz64 in favor of ffsll, Jan Kiszka, 2009/07/04
Re: [Qemu-devel] Re: [PATCH] Use ffs in favor of ffsll, Christoph Egger, 2009/07/02