auto import from //depot/cupcake/@135843
diff --git a/libm/src/s_scalbnl.c b/libm/src/s_scalbnl.c
new file mode 100644
index 0000000..c645d00
--- /dev/null
+++ b/libm/src/s_scalbnl.c
@@ -0,0 +1,71 @@
+/* @(#)s_scalbn.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: src/lib/msun/src/s_scalbnl.c,v 1.1 2005/03/07 04:52:58 das Exp $";
+#endif
+
+/*
+ * scalbnl (long double x, int n)
+ * scalbnl(x,n) returns x* 2**n computed by exponent
+ * manipulation rather than by actually performing an
+ * exponentiation or a multiplication.
+ */
+
+/*
+ * We assume that a long double has a 15-bit exponent. On systems
+ * where long double is the same as double, scalbnl() is an alias
+ * for scalbn(), so we don't use this routine.
+ */
+
+#include <sys/cdefs.h>
+#include <float.h>
+#include <math.h>
+
+#include "fpmath.h"
+
+#if LDBL_MAX_EXP != 0x4000
+#error "Unsupported long double format"
+#endif
+
+static const long double
+huge = 0x1p16000L,
+tiny = 0x1p-16000L;
+
+long double
+scalbnl (long double x, int n)
+{
+ union IEEEl2bits u;
+ int k;
+ u.e = x;
+ k = u.bits.exp; /* extract exponent */
+ if (k==0) { /* 0 or subnormal x */
+ if ((u.bits.manh|u.bits.manl)==0) return x; /* +-0 */
+ u.e *= 0x1p+128;
+ k = u.bits.exp - 128;
+ if (n< -50000) return tiny*x; /*underflow*/
+ }
+ if (k==0x7fff) return x+x; /* NaN or Inf */
+ k = k+n;
+ if (k >= 0x7fff) return huge*copysignl(huge,x); /* overflow */
+ if (k > 0) /* normal result */
+ {u.bits.exp = k; return u.e;}
+ if (k <= -128)
+ if (n > 50000) /* in case integer overflow in n+k */
+ return huge*copysign(huge,x); /*overflow*/
+ else return tiny*copysign(tiny,x); /*underflow*/
+ k += 128; /* subnormal result */
+ u.bits.exp = k;
+ return u.e*0x1p-128;
+}
+
+__strong_reference(scalbnl, ldexpl);