From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 21 Jan 2013 19:28:23 +0000 (-0700)
Subject: Add hweight64()
X-Git-Tag: fio-2.0.14~108
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=def823d406ad78d3f9690ee8804e743e1d5a8aff

Add hweight64()

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/lib/hweight.c b/lib/hweight.c
index 738ed277..bc9b51bc 100644
--- a/lib/hweight.c
+++ b/lib/hweight.c
@@ -17,3 +17,17 @@ unsigned int hweight32(uint32_t w)
 	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
+}
diff --git a/lib/hweight.h b/lib/hweight.h
index 1965eaa6..68861ddd 100644
--- a/lib/hweight.h
+++ b/lib/hweight.h
@@ -5,5 +5,6 @@
 
 unsigned int hweight8(uint8_t w);
 unsigned int hweight32(uint32_t w);
+unsigned int hweight64(uint64_t w);
 
 #endif