Messages in this thread Patch in this message | | | Date | Sun, 18 Jan 2015 11:06:47 -0800 | From | tip-bot for Martin Kepplinger <> | Subject | [tip:core/types] bitops: Add sign_extend8(), 16 and 64 functions |
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Commit-ID: 7e9358073d3f0ed0a028c48aa54009b3296dffc9 Gitweb: http://git.kernel.org/tip/7e9358073d3f0ed0a028c48aa54009b3296dffc9 Author: Martin Kepplinger <martink@posteo.de> AuthorDate: Mon, 12 Jan 2015 18:22:50 +0100 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Sun, 18 Jan 2015 20:03:51 +0100
bitops: Add sign_extend8(), 16 and 64 functions
This adds helper functions for sign-extending signed values of any lower (hardware-)given size to s8, s16 or s64 respectively, just like sign_extend32() for s32.
This completes the sign_extend*() API family to work on all bit sizes like most other bitops APIs do.
Suggested-by: Christoph Muellner <christoph.muellner@theobroma-systems.com> Signed-off-by: Martin Kepplinger <martink@posteo.de> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maxime COQUELIN <maxime.coquelin@st.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1421083370-24924-1-git-send-email-martink@posteo.de Signed-off-by: Ingo Molnar <mingo@kernel.org> --- include/linux/bitops.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 5d858e0..9c31680 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -161,6 +161,28 @@ static inline __u8 ror8(__u8 word, unsigned int shift) } /** + * sign_extend8 - sign extend a 8-bit value using specified bit as sign-bit + * @value: value to sign extend + * @index: 0 based bit index (0<=index<8) to sign bit + */ +static inline __s8 sign_extend8(__u8 value, int index) +{ + __u8 shift = 7 - index; + return (__s8)(value << shift) >> shift; +} + +/** + * sign_extend16 - sign extend a 16-bit value using specified bit as sign-bit + * @value: value to sign extend + * @index: 0 based bit index (0<=index<16) to sign bit + */ +static inline __s16 sign_extend16(__u16 value, int index) +{ + __u8 shift = 15 - index; + return (__s16)(value << shift) >> shift; +} + +/** * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit * @value: value to sign extend * @index: 0 based bit index (0<=index<32) to sign bit @@ -171,6 +193,17 @@ static inline __s32 sign_extend32(__u32 value, int index) return (__s32)(value << shift) >> shift; } +/** + * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit + * @value: value to sign extend + * @index: 0 based bit index (0<=index<64) to sign bit + */ +static inline __s64 sign_extend64(__u64 value, int index) +{ + __u8 shift = 63 - index; + return (__s64)(value << shift) >> shift; +} + static inline unsigned fls_long(unsigned long l) { if (sizeof(l) == 4)
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