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-rw-r--r--include/linux/bitops.h15
1 files changed, 14 insertions, 1 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index e63553386..defeaac07 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -107,7 +107,7 @@ static inline __u64 ror64(__u64 word, unsigned int shift)
*/
static inline __u32 rol32(__u32 word, unsigned int shift)
{
- return (word << shift) | (word >> (32 - shift));
+ return (word << shift) | (word >> ((-shift) & 31));
}
/**
@@ -164,6 +164,8 @@ static inline __u8 ror8(__u8 word, unsigned int 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
+ *
+ * This is safe to use for 16- and 8-bit types as well.
*/
static inline __s32 sign_extend32(__u32 value, int index)
{
@@ -171,6 +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)