Signed-off-by: Aryan Gupta <garyan447@xxxxxxxxx>
---
Thank you Vicent for the guidance. I am still not sure how
to do the performance measurement for this improvement. Any
guidance would be appreciated.
ewah/ewah_bitmap.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/ewah/ewah_bitmap.c b/ewah/ewah_bitmap.c
index 8785cbc54a..1a75f50682 100644
--- a/ewah/ewah_bitmap.c
+++ b/ewah/ewah_bitmap.c
@@ -257,12 +257,15 @@ void ewah_each_bit(struct ewah_bitmap *self, void (*callback)(size_t, void*), vo
for (k = 0; k < rlw_get_literal_words(word); ++k) {
int c;
- /* todo: zero count optimization */
- for (c = 0; c < BITS_IN_EWORD; ++c, ++pos) {
- if ((self->buffer[pointer] & ((eword_t)1 << c)) != 0)
- callback(pos, payload);
+ eword_t bitset = self->buffer[pointer];
+ while(bitset != 0) {
+ eword_t t = bitset & -bitset;
+ int r = __builtin_ctzl(bitset);
+ bitset ^= t;
+ callback(pos+r, payload);
}
-
+
+ pos += BITS_IN_EWORD;
++pointer;
}
}
--
2.25.1
