Index: uspace/lib/math/generic/scalbn.c
===================================================================
--- uspace/lib/math/generic/scalbn.c	(revision 21d5236e01e2dbe2524b37d4a3ac45ca7617ae11)
+++ uspace/lib/math/generic/scalbn.c	(revision 21d5236e01e2dbe2524b37d4a3ac45ca7617ae11)
@@ -0,0 +1,59 @@
+/*
+ * ====================================================
+ * Copyright (C) 2004 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice 
+ * is preserved.
+ * ====================================================
+ */
+
+/** @addtogroup libmath
+ * @{
+ */
+/** @file scalbn mathematical function
+ */
+
+#include <math.h>
+#include <stdint.h>
+
+
+/* scalbn(x,n) returns x* 2**n  computed by  exponent
+ * manipulation rather than by actually performing an
+ * exponentiation or a multiplication.
+ */
+
+double scalbn(double x, int n)
+{
+	union {double f; uint64_t i;} u;
+	double_t y = x;
+
+	if (n > 1023) {
+		y *= 0x1p1023;
+ 		n -= 1023;
+		if (n > 1023) {
+			y *= 0x1p1023;
+			n -= 1023;
+			if (n > 1023)
+				n = 1023;
+		}
+	} else if (n < -1022) {
+        /* make sure final n < -53 to avoid double
+           rounding in the subnormal range */
+		y *= 0x1p-1022 * 0x1p53;
+		n += 1022 - 53;
+		if (n < -1022) {
+			y *= 0x1p-1022 * 0x1p53;
+			n += 1022 - 53;
+			if (n < -1022)
+				n = -1022;
+		}
+	}
+	u.i = (uint64_t)(0x3ff+n)<<52;
+	x = y * u.f;
+
+	return x;
+}
+
+/** @}
+ */