Count how many bits set in the bitmap.
Signed-off-by: Peter Xu <[email protected]>
---
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;
+}
--
2.7.4
