Add logbl(3) to libm.

2 files changed, 61 insertions, 0 deletions

diff --git a/lib/msun/src/s_logb.c b/lib/msun/src/s_logb.c
index f667bf2..4091429 100644
--- a/lib/msun/src/s_logb.c
+++ b/lib/msun/src/s_logb.c
@@ -20,6 +20,8 @@ static char rcsid[] = "$FreeBSD$";
  * Use ilogb instead.
  */
 
+#include <float.h>
+
 #include "math.h"
 #include "math_private.h"
 
@@ -42,3 +44,7 @@ logb(double x)
 	} else
 		return (double) ((ix>>20)-1023);
 }
+
+#if (LDBL_MANT_DIG == 53)
+__weak_reference(logb, logbl);
+#endif
diff --git a/lib/msun/src/s_logbl.c b/lib/msun/src/s_logbl.c
new file mode 100644
index 0000000..7e88e36
--- /dev/null
+++ b/lib/msun/src/s_logbl.c
@@ -0,0 +1,55 @@
+/*
+ * From: @(#)s_ilogb.c 5.1 93/09/24
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#ifndef lint
+static char rcsid[] = "$FreeBSD$";
+#endif
+
+#include <float.h>
+#include <limits.h>
+#include <math.h>
+
+#include "fpmath.h"
+
+long double
+logbl(long double x)
+{
+	union IEEEl2bits u;
+	unsigned long m;
+	int b;
+
+	u.e = x;
+	if (u.bits.exp == 0) {
+		if ((u.bits.manl | u.bits.manh) == 0) {	/* x == 0 */
+			u.bits.sign = 1;
+			return (1.0L / u.e);
+		}
+		/* denormalized */
+		if (u.bits.manh == 0) {
+			m = 1lu << (LDBL_MANL_SIZE - 1);
+			for (b = LDBL_MANH_SIZE; !(u.bits.manl & m); m >>= 1)
+				b++;
+		} else {
+			m = 1lu << (LDBL_MANH_SIZE - 1);
+			for (b = 0; !(u.bits.manh & m); m >>= 1)
+				b++;
+		}
+#ifdef LDBL_IMPLICIT_NBIT
+		b++;
+#endif
+		return ((long double)(LDBL_MIN_EXP - b - 1));
+	}
+	if (u.bits.exp < (LDBL_MAX_EXP << 1) - 1)	/* normal */
+		return ((long double)(u.bits.exp - LDBL_MAX_EXP + 1));
+	else						/* +/- inf or nan */
+		return (x * x);
+}