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Re: [Qemu-devel] [RFC 04/29] bitmap: introduce bitmap_invert()
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [RFC 04/29] bitmap: introduce bitmap_invert() |
Date: |
Wed, 2 Aug 2017 11:20:43 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Tue, Aug 01, 2017 at 09:40:09AM +0100, Dr. David Alan Gilbert wrote:
> * Peter Xu (address@hidden) wrote:
> > On Mon, Jul 31, 2017 at 06:11:56PM +0100, Dr. David Alan Gilbert wrote:
> > > * Peter Xu (address@hidden) wrote:
> > > > It is used to invert the whole bitmap.
> > >
> > > Would it be easier to change bitmap_complement to use ^
> > > in it's macro and slow_bitmap_complement, and then you could call it
> > > with src==dst to do the same thing with just that small change?
> >
> > Or, I can directly use that and drop this patch. :-)
>
> Yes, that's fine - note the only difference I see is what happens to the
> bits in the last word after the end of the count; your code leaves them
> as is, the complement code will zero them on the destination I think.
I see. I believe both should work since bitmap users should not
use those bits after all (considering those bits are outside range of
valid bits when declaring the bitmap). Thanks,
--
Peter Xu