[ovs-dev] [PATCH 1/2] util: Make ctz() handle 64-bit integers instead of a separate ctz64().

[Ben Pfaff]

On Mon, Nov 18, 2013 at 02:38:50PM -0800, Jarno Rajahalme wrote:
> One  question still:
> 
> On Nov 18, 2013, at 1:19 PM, Ben Pfaff <blp at nicira.com> wrote:
> >     return popcount(n) + popcount(n >> 32);
> > @@ -341,7 +332,7 @@ ctz(uint32_t n)
> > static inline int
> > ctz64(uint64_t n)
> > {
> > -    return n ? raw_ctz64(n) : 64;
> > +    return n ? raw_ctz(n) : 64;
> > }
> > 
> 
> Did you intend to define ctz(uint64_t) and not define ctz64() at all?

I got the commit message wrong, sorry.  This commit is intended to be
entirely about raw_ctz() and raw_ctz64(), specifically getting rid of
the latter.  It looks like I got the code right but the commit message
totally wrong.  Here's what I've now edited the commit message to:

    util: Make raw_ctz() accept 64-bit integers.
    
    Having a single function that can do raw_ctz() on any integer type is
    easier for callers to get right, and there is no real downside in the
    implementation.
    
    Signed-off-by: Ben Pfaff <blp at nicira.com>
    Acked-by: Jarno Rajahalme <jrajahalme at nicira.com>

I think I got confused because originally I did want to get rid of
ctz64().  However that's not possible with the current definition of
ctz() and ctz64(), since the return value for n==0 differs in each
case.

Does the commit make sense with the correct log message?

Thanks,

Ben.