From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Duplicate the libxfs bit manipulation functions -- this is for programs
that don't need libxfs.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
include/bitops.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/include/bitops.h b/include/bitops.h
index 7774950..dd561c2 100644
--- a/include/bitops.h
+++ b/include/bitops.h
@@ -56,4 +56,62 @@ static inline unsigned fls_long(unsigned long l)
*/
#define ffz(x) ffs(~(x))
+/*
+ * XFS bit manipulation routines. Repeated here so that some programs
+ * don't have to link in all of libxfs just to have bit manipulation.
+ */
+
+/*
+ * masks with n high/low bits set, 64-bit values
+ */
+static inline uint64_t mask64hi(int n)
+{
+ return (uint64_t)-1 << (64 - (n));
+}
+static inline uint32_t mask32lo(int n)
+{
+ return ((uint32_t)1 << (n)) - 1;
+}
+static inline uint64_t mask64lo(int n)
+{
+ return ((uint64_t)1 << (n)) - 1;
+}
+
+/* Get high bit set out of 32-bit argument, -1 if none set */
+static inline int highbit32(uint32_t v)
+{
+ return fls(v) - 1;
+}
+
+/* Get high bit set out of 64-bit argument, -1 if none set */
+static inline int highbit64(uint64_t v)
+{
+ return fls64(v) - 1;
+}
+
+/* Get low bit set out of 32-bit argument, -1 if none set */
+static inline int lowbit32(uint32_t v)
+{
+ return ffs(v) - 1;
+}
+
+/* Get low bit set out of 64-bit argument, -1 if none set */
+static inline int lowbit64(uint64_t v)
+{
+ uint32_t w = (uint32_t)v;
+ int n = 0;
+
+ if (w) { /* lower bits */
+ n = ffs(w);
+ } else { /* upper bits */
+ w = (uint32_t)(v >> 32);
+ if (w) {
+ n = ffs(w);
+ if (n)
+ n += 32;
+ }
+ }
+ return n - 1;
+}
+
#endif
--
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