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authorRich Felker <dalias@aerifal.cx>2020-06-11 00:12:48 -0400
committerRich Felker <dalias@aerifal.cx>2020-06-11 00:12:48 -0400
commitca36573ecfbbef7a1563aaa1a8486081f8c9fdda (patch)
tree5f85ff1f9d9b28c986415d42b226009fb63daf0c
parent1fc67fc117f9d25d240d46bbef78ebccacec7097 (diff)
downloadmusl-ca36573ecfbbef7a1563aaa1a8486081f8c9fdda.tar.gz
add fallback a_clz_32 implementation
some archs already have a_clz_32, used to provide a_ctz_32, but it hasn't been mandatory because it's not used anywhere yet. mallocng will need it, however, so add it now. it should probably be optimized better, but doesn't seem to make a difference at present.
-rw-r--r--src/internal/atomic.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/src/internal/atomic.h b/src/internal/atomic.h
index f938879b..99539cc0 100644
--- a/src/internal/atomic.h
+++ b/src/internal/atomic.h
@@ -315,4 +315,19 @@ static inline int a_clz_64(uint64_t x)
}
#endif
+#ifndef a_clz_32
+#define a_clz_32 a_clz_32
+static inline int a_clz_32(uint32_t x)
+{
+ x--;
+ x |= x >> 1;
+ x |= x >> 2;
+ x |= x >> 4;
+ x |= x >> 8;
+ x |= x >> 16;
+ x++;
+ return 31-a_ctz_32(x);
+}
+#endif
+
#endif