BSD 4.4 Lite Lib Sources

1 files changed, 74 insertions, 0 deletions

diff --git a/lib/libc/quad/floatdidf.c b/lib/libc/quad/floatdidf.c
new file mode 100644
index 0000000..7b90f6e
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+++ b/lib/libc/quad/floatdidf.c
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+/*-
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. 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.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)floatdidf.c	8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+
+#include "quad.h"
+
+/*
+ * Convert (signed) quad to double.
+ */
+double
+__floatdidf(x)
+	quad_t x;
+{
+	double d;
+	union uu u;
+	int neg;
+
+	/*
+	 * Get an unsigned number first, by negating if necessary.
+	 */
+	if (x < 0)
+		u.q = -x, neg = 1;
+	else
+		u.q = x, neg = 0;
+
+	/*
+	 * Now u.ul[H] has the factor of 2^32 (or whatever) and u.ul[L]
+	 * has the units.  Ideally we could just set d, add LONG_BITS to
+	 * its exponent, and then add the units, but this is portable
+	 * code and does not know how to get at an exponent.  Machine-
+	 * specific code may be able to do this more efficiently.
+	 */
+	d = (double)u.ul[H] * ((1 << (LONG_BITS - 2)) * 4.0);
+	d += u.ul[L];
+
+	return (neg ? -d : d);
+}