From: Willy Tarreau <w@1wt.eu>
Date: Mon, 15 Oct 2018 07:33:41 +0000 (+0200)
Subject: MINOR: tools: add a new function atleast2() to test masks for more than 1 bit
X-Git-Tag: v1.9-dev4~40
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=98d334bd945b038b7340af451ed7873143076a4b;p=thirdparty%2Fhaproxy.git

MINOR: tools: add a new function atleast2() to test masks for more than 1 bit

For threads it's common to have to check if a mask contains more than
one bit set. Let's have this "atleast2()" function report this.
---

diff --git a/include/common/standard.h b/include/common/standard.h
index fabe97276b..3e13f301c3 100644
--- a/include/common/standard.h
+++ b/include/common/standard.h
@@ -801,6 +801,12 @@ static inline unsigned int my_popcountl(unsigned long a)
 	return cnt;
 }
 
+/* returns non-zero if <a> has at least 2 bits set */
+static inline unsigned long atleast2(unsigned long a)
+{
+	return a & (a - 1);
+}
+
 /* Simple ffs implementation. It returns the position of the lowest bit set to
  * one. It is illegal to call it with a==0 (undefined result).
  */