From ca36573ecfbbef7a1563aaa1a8486081f8c9fdda Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Thu, 11 Jun 2020 00:12:48 -0400
Subject: [PATCH] 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.
---
src/internal/atomic.h | 15 +++++++++++++++
1 file changed, 15 insertions(+)
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