1 files changed, 19 insertions, 0 deletions
diff --git a/src/math/logbl.c b/src/math/logbl.c
new file mode 100644
index 00000000..5d04abd7
--- /dev/null
+++ b/src/math/logbl.c
@@ -0,0 +1,19 @@
+#include <limits.h>
+#include "libm.h"
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double logbl(long double x)
+{
+	return logb(x);
+}
+#else
+long double logbl(long double x)
+{
+	int i = ilogbl(x);
+
+	if (i == FP_ILOGB0)
+		return -1.0/fabsl(x);
+	if (i == FP_ILOGBNAN || i == INT_MAX)
+		return x * x;
+	return i;
+}
+#endif