Add hweight64()
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/lib/hweight.c b/lib/hweight.c
index 738ed27..bc9b51b 100644
--- a/lib/hweight.c
+++ b/lib/hweight.c
@@ -17,3 +17,17 @@
res = res + (res >> 8);
return (res + (res >> 16)) & 0x000000FF;
}
+
+unsigned int hweight64(uint64_t w)
+{
+#if BITS_PER_LONG == 32
+ return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w);
+#else
+ uint64_t res = w - ((w >> 1) & 0x5555555555555555ul);
+ res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
+ res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
+ res = res + (res >> 8);
+ res = res + (res >> 16);
+ return (res + (res >> 32)) & 0x00000000000000FFul;
+#endif
+}