Months back, this was discussed, see https://lkml.org/lkml/2015/1/18/289
The result was the 64-bit version being "likely fine", "valuable" and
"correct". The discussion only fell asleep but since there are possible
users, let's add it.
Signed-off-by: Martin Kepplinger <martin.kepplin...@theobroma-systems.com>
---
include/linux/bitops.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 2177c01..1672b74 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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