From fc7deeea26af3d08f45bad85b8bd3fc3d790a090 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Wed, 30 Aug 2017 16:31:59 +0800 Subject: [PATCH] bitmap: introduce bitmap_count_one() Count how many bits set in the bitmap. Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Peter Xu Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- 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 c318da12d7..2718706edb 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -82,6 +82,7 @@ int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, long bits); int slow_bitmap_intersects(const unsigned long *bitmap1, const unsigned long *bitmap2, long bits); +long slow_bitmap_count_one(const unsigned long *bitmap, long nbits); static inline unsigned long *bitmap_try_new(long nbits) { @@ -216,6 +217,15 @@ static inline int bitmap_intersects(const unsigned long *src1, } } +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 efced9a7d8..90a42ff625 100644 --- a/util/bitmap.c +++ b/util/bitmap.c @@ -355,3 +355,18 @@ int slow_bitmap_intersects(const unsigned long *bitmap1, } return 0; } + +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; +}