linux-kernel - [PATCH] kernel: add bit rotation helpers for 16 and 8 bit

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Date:	Tue, 18 Mar 2008 13:24:01 -0700
From:	Harvey Harrison <harvey.harrison@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Johannes Berg <johannes@...solutions.net>,
	Randy Dunlap <randy.dunlap@...cle.com>
Subject: [PATCH] kernel: add bit rotation helpers for 16 and 8 bit

Will replace open-coded variants elsewhere.  Done in the same
style as the 32-bit versions.

Signed-off-by: Harvey Harrison <harvey.harrison@...il.com>
---
Andrew, these will be used to replace some open-coded variants in the
mac80211 code, there are currently no users so it can go in with little
risk.

Randy, CC'd in case I screwed up the kerneldoc.

 include/linux/bitops.h |   40 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 69c1edb..40d5473 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -65,6 +65,46 @@ static inline __u32 ror32(__u32 word, unsigned int shift)
 	return (word >> shift) | (word << (32 - shift));
 }
 
+/**
+ * rol16 - rotate a 16-bit value left
+ * @word: value to rotate
+ * @shift: bits to roll
+ */
+static inline __u16 rol16(__u16 word, unsigned int shift)
+{
+	return (word << shift) | (word >> (16 - shift));
+}
+
+/**
+ * ror16 - rotate a 16-bit value right
+ * @word: value to rotate
+ * @shift: bits to roll
+ */
+static inline __u16 ror16(__u16 word, unsigned int shift)
+{
+	return (word >> shift) | (word << (16 - shift));
+}
+
+/**
+ * rol8 - rotate an 8-bit value left
+ * @word: value to rotate
+ * @shift: bits to roll
+ */
+static inline __u8 rol8(__u8 word, unsigned int shift)
+{
+	return (word << shift) | (word >> (8 - shift));
+}
+
+/**
+ * ror8 - rotate an 8-bit value right
+ * @word: value to rotate
+ * @shift: bits to roll
+ */
+static inline __u8 ror8(__u8 word, unsigned int shift)
+{
+	return (word >> shift) | (word << (8 - shift));
+}
+
 static inline unsigned fls_long(unsigned long l)
 {
 	if (sizeof(l) == 4)
-- 
1.5.4.4.684.g0e08



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