usr: libc: Add math.h + musl math impl portexpt

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/lib/libc/src/musl-math/scalb.c b/lib/libc/src/musl-math/scalb.c
new file mode 100644
index 0000000..efe69e6
--- /dev/null
+++ b/lib/libc/src/musl-math/scalb.c
@@ -0,0 +1,35 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_scalb.c */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+/*
+ * scalb(x, fn) is provide for
+ * passing various standard test suite. One
+ * should use scalbn() instead.
+ */
+
+#define _GNU_SOURCE
+#include <math.h>
+
+double scalb(double x, double fn)
+{
+	if (isnan(x) || isnan(fn))
+		return x*fn;
+	if (!isfinite(fn)) {
+		if (fn > 0.0)
+			return x*fn;
+		else
+			return x/(-fn);
+	}
+	if (rint(fn) != fn) return (fn-fn)/(fn-fn);
+	if ( fn > 65000.0) return scalbn(x, 65000);
+	if (-fn > 65000.0) return scalbn(x,-65000);
+	return scalbn(x,(int)fn);
+}