Messages in this thread Patch in this message | | | From | Martin Kepplinger <> | Subject | [PATCH 2/2] bitops.h: Add sign_extend64() API | Date | Tue, 20 Jan 2015 13:30:55 +0100 |
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Add sign_extend64() for sign extending any (hardware-)given signed value greater than 32 bits to s64.
Suggested-by: Christoph Muellner <christoph.muellner@theobroma-systems.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Martin Kepplinger <martink@posteo.de> --- include/linux/bitops.h | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 336f22b..2fd47c8 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -173,6 +173,17 @@ 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) -- 2.1.4
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