* Peter Xu (pet...@redhat.com) wrote:
> Count how many bits set in the bitmap.
>
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> include/qemu/bitmap.h | 10 ++++++++++
> util/bitmap.c | 15 +++++++++++++++
> 2 files changed, 25 insertions(+)
>
> diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h
> index 460d899..9c18da0 100644
> --- a/include/qemu/bitmap.h
> +++ b/include/qemu/bitmap.h
> @@ -83,6 +83,7 @@ int slow_bitmap_andnot(unsigned long *dst, const unsigned
> long *bitmap1,
> int slow_bitmap_intersects(const unsigned long *bitmap1,
> const unsigned long *bitmap2, long bits);
> void slow_bitmap_invert(unsigned long *bitmap, long nbits);
> +long slow_bitmap_count_one(const unsigned long *bitmap, long nbits);
>
> static inline unsigned long *bitmap_try_new(long nbits)
> {
> @@ -226,6 +227,15 @@ static inline void bitmap_invert(unsigned long *bitmap,
> long nbits)
> }
> }
>
> +static inline long bitmap_count_one(const unsigned long *bitmap, long nbits)
> +{
> + if (small_nbits(nbits)) {
> + return (ctpopl(*bitmap & BITMAP_LAST_WORD_MASK(nbits)));
> + } else {
> + return slow_bitmap_count_one(bitmap, nbits);
> + }
> +}
> +
> void bitmap_set(unsigned long *map, long i, long len);
> void bitmap_set_atomic(unsigned long *map, long i, long len);
> void bitmap_clear(unsigned long *map, long start, long nr);
> diff --git a/util/bitmap.c b/util/bitmap.c
> index 9b7408c..73a1063 100644
> --- a/util/bitmap.c
> +++ b/util/bitmap.c
> @@ -368,3 +368,18 @@ void slow_bitmap_invert(unsigned long *bitmap, long
> nbits)
> bitmap[k] ^= BITMAP_LAST_WORD_MASK(nbits);
> }
> }
> +
> +long slow_bitmap_count_one(const unsigned long *bitmap, long nbits)
> +{
> + long k, lim = nbits/BITS_PER_LONG, result = 0;
> +
> + for (k = 0; k < lim; k++) {
> + result += ctpopl(bitmap[k]);
> + }
> +
> + if (nbits % BITS_PER_LONG) {
> + result += ctpopl(bitmap[k] & BITMAP_LAST_WORD_MASK(nbits));
> + }
> +
> + return result;
> +}
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
(I checked what happens with BITMAP_LAST_WORD_MASK(0) interestingly it's
all 1 - so you do need that if)
> --
> 2.7.4
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
