1 files changed, 140 insertions, 0 deletions
diff --git a/lib/libc/arch/sh/gen/ldexp.c b/lib/libc/arch/sh/gen/ldexp.c
new file mode 100644
index 00000000000..6c3723ded7c
--- /dev/null
+++ b/lib/libc/arch/sh/gen/ldexp.c
@@ -0,0 +1,140 @@
+/*	$OpenBSD: ldexp.c,v 1.1 2006/10/10 22:07:10 miod Exp $	*/
+/*
+ * Copyright (c) 1992, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This software was developed by the Computer Systems Engineering group
+ * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
+ * contributed to Berkeley.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * from: Header: ldexp.c,v 1.1 91/07/07 04:28:19 torek Exp
+ */
+
+#include <sys/types.h>
+#include <machine/ieee.h>
+#include <errno.h>
+
+/*
+ * double ldexp(double val, int exp)
+ * returns: val * (2**exp)
+ */
+double
+ldexp(val, exp)
+	double val;
+	int exp;
+{
+	register int oldexp, newexp, mulexp;
+	union doub {
+		double v;
+		struct ieee_double s;
+	} u, mul;
+
+	/*
+	 * If input is zero, or no change, just return input.
+	 * Likewise, if input is Inf or NaN, just return it.
+	 */
+	u.v = val;
+	oldexp = u.s.dbl_exp;
+	if (val == 0 || exp == 0 || oldexp == DBL_EXP_INFNAN)
+		return (val);
+
+	/*
+	 * Compute new exponent and check for over/under flow.
+	 * Underflow, unfortunately, could mean switching to denormal.
+	 * If result out of range, set ERANGE and return 0 if too small
+	 * or Inf if too big, with the same sign as the input value.
+	 */
+	newexp = oldexp + exp;
+	if (newexp >= DBL_EXP_INFNAN) {
+		/* u.s.dbl_sign = val < 0; -- already set */
+		u.s.dbl_exp = DBL_EXP_INFNAN;
+		u.s.dbl_frach = u.s.dbl_fracl = 0;
+		errno = ERANGE;
+		return (u.v);		/* Inf */
+	}
+	if (newexp <= 0) {
+		/*
+		 * The output number is either a denormal or underflows
+		 * (see comments in machine/ieee.h).
+		 */
+		if (newexp <= -DBL_FRACBITS) {
+			/* u.s.dbl_sign = val < 0; -- already set */
+			u.s.dbl_exp = 0;
+			u.s.dbl_frach = u.s.dbl_fracl = 0;
+			errno = ERANGE;
+			return (u.v);		/* zero */
+		}
+		/*
+		 * We are going to produce a denorm.  Our `exp' argument
+		 * might be as small as -2097, and we cannot compute
+		 * 2^-2097, so we may have to do this as many as three
+		 * steps (not just two, as for positive `exp's below).
+		 */
+		mul.v = 0;
+		while (exp <= -DBL_EXP_BIAS) {
+			mul.s.dbl_exp = 1;
+			val *= mul.v;
+			exp += DBL_EXP_BIAS - 1;
+		}
+		mul.s.dbl_exp = exp + DBL_EXP_BIAS;
+		val *= mul.v;
+		return (val);
+	}
+
+	/*
+	 * Newexp is positive.
+	 *
+	 * If oldexp is zero, we are starting with a denorm, and simply
+	 * adjusting the exponent will produce bogus answers.  We need
+	 * to fix that first.
+	 */
+	if (oldexp == 0) {
+		/*
+		 * Multiply by 2^mulexp to make the number normalizable.
+		 * We cannot multiply by more than 2^1023, but `exp'
+		 * argument might be as large as 2046.  A single
+		 * adjustment, however, will normalize the number even
+		 * for huge `exp's, and then we can use exponent
+		 * arithmetic just as for normal `double's.
+		 */
+		mulexp = exp <= DBL_EXP_BIAS ? exp : DBL_EXP_BIAS;
+		mul.v = 0;
+		mul.s.dbl_exp = mulexp + DBL_EXP_BIAS;
+		val *= mul.v;
+		if (mulexp == exp)
+			return (val);
+		u.v = val;
+		newexp -= mulexp;
+	}
+
+	/*
+	 * Both oldexp and newexp are positive; just replace the
+	 * old exponent with the new one.
+	 */
+	u.s.dbl_exp = newexp;
+	return (u.v);
+}