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

From: Randy Dunlap
Date: Thu Mar 20 2008 - 07:21:19 EST


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

Signed-off-by: Harvey Harrison <harvey.harrison@xxxxxxxxx>
---
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.

Looks good.
Acked-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>


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)


--
~Randy
--
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