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Re: [Qemu-devel] [PATCH 1/7] qcow2: Make get_bits_from_size() common
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH 1/7] qcow2: Make get_bits_from_size() common |
Date: |
Fri, 24 Sep 2010 09:37:49 +0100 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Fri, Sep 24, 2010 at 01:50:39AM +0400, malc wrote:
> On Thu, 23 Sep 2010, Stefan Hajnoczi wrote:
>
> > The get_bits_from_size() calculates the log base-2 of a number. This is
> > useful in bit manipulation code working with power-of-2s.
> >
> > Currently used by qcow2 and needed by qed in a follow-on patch.
>
> int ilog2 (size_t size)
> {
> if (size & (size - 1))
> return -1;
>
> return __builtin_ctzl (size);
> }
>
> Ifdef WIN64 omitted for brevity.
What is the situation with WIN64?
Stefan
- [Qemu-devel] [PATCH 0/7] qed: Add QEMU Enhanced Disk format, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 3/7] cutils: qemu_iovec_copy and qemu_iovec_memset, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 7/7] qed: Consistency check support, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 5/7] qed: Table, L2 cache, and cluster functions, Stefan Hajnoczi, 2010/09/23
- [Qemu-devel] [PATCH 1/7] qcow2: Make get_bits_from_size() common, Stefan Hajnoczi, 2010/09/23
[Qemu-devel] [PATCH 2/7] cutils: Add bytes_to_str() to format byte values, Stefan Hajnoczi, 2010/09/23
[Qemu-devel] [PATCH 4/7] qed: Add QEMU Enhanced Disk image format, Stefan Hajnoczi, 2010/09/23
[Qemu-devel] [PATCH 6/7] qed: Read/write support, Stefan Hajnoczi, 2010/09/23
Re: [Qemu-devel] [PATCH 0/7] qed: Add QEMU Enhanced Disk format, Avi Kivity, 2010/09/27
Re: [Qemu-devel] [PATCH 0/7] qed: Add QEMU Enhanced Disk format, Avi Kivity, 2010/09/27