2008-03-19 19:31:56

by Harvey Harrison

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 <[email protected]>
---
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

2008-03-20 11:21:17

by Randy Dunlap

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

Harvey Harrison wrote:
> Will replace open-coded variants elsewhere. Done in the same
> style as the 32-bit versions.
>
> Signed-off-by: Harvey Harrison <[email protected]>
> ---
> 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 <[email protected]>


> 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