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Re: [Qemu-devel] [PATCH 2/7] Convert (ffs(val) - 1) to ctz32(val)
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH 2/7] Convert (ffs(val) - 1) to ctz32(val) |
Date: |
Tue, 17 Mar 2015 14:54:38 +0000 |
On Tue, Mar 17, 2015 at 12:09 PM, Peter Maydell
<address@hidden> wrote:
> On 17 March 2015 at 11:56, Stefan Hajnoczi <address@hidden> wrote:
>> This commit was generated mechanically by coccinelle from the following
>> semantic patch:
>>
>> @@
>> expression val;
>> @@
>> - (ffs(val) - 1)
>> + ctz32(val)
>
> Did you check all these callsites to make sure that the value
> passed in can never be zero? (ffs(0) - 1) is -1 whereas
> ctz32(0) is 32...
I have done that now and found 2 cases where it's possible. They will
be moved to separate patches in v2.
Stefan
- [Qemu-devel] [PATCH 1/7] bt-sdp: fix broken uuids power-of-2 calculation, (continued)
- [Qemu-devel] [PATCH 1/7] bt-sdp: fix broken uuids power-of-2 calculation, Stefan Hajnoczi, 2015/03/17
- [Qemu-devel] [PATCH 6/7] os-win32: drop ffs(3) prototype, Stefan Hajnoczi, 2015/03/17
- [Qemu-devel] [PATCH 4/7] sd: convert sd_normal_command() ffs(3) call to ctz32(), Stefan Hajnoczi, 2015/03/17
- [Qemu-devel] [PATCH 3/7] Convert ffs() != 0 callers to ctz32(), Stefan Hajnoczi, 2015/03/17
- [Qemu-devel] [PATCH 7/7] checkpatch: complain about ffs(3) calls, Stefan Hajnoczi, 2015/03/17
- [Qemu-devel] [PATCH 5/7] omap_intc: convert ffs(3) to ctz32() in omap_inth_sir_update(), Stefan Hajnoczi, 2015/03/17
- [Qemu-devel] [PATCH 2/7] Convert (ffs(val) - 1) to ctz32(val), Stefan Hajnoczi, 2015/03/17
- Re: [Qemu-devel] [PATCH 0/7] Convert ffs(3) to ctz32(), Stefan Hajnoczi, 2015/03/17