From 5bc737f35262327ca86ef96a7cbc6680c8eeb2ea Mon Sep 17 00:00:00 2001
From: das <das@FreeBSD.org>
Date: Wed, 3 Jan 2007 04:58:54 +0000
Subject: Import of the latest gdtoa sources, which include fixes for minor
 problems relating to NaNs and rounding.

---
 contrib/gdtoa/qnan.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 contrib/gdtoa/qnan.c

(limited to 'contrib/gdtoa/qnan.c')

diff --git a/contrib/gdtoa/qnan.c b/contrib/gdtoa/qnan.c
new file mode 100644
index 0000000..118e749
--- /dev/null
+++ b/contrib/gdtoa/qnan.c
@@ -0,0 +1,110 @@
+/****************************************************************
+
+The author of this software is David M. Gay.
+
+Copyright (C) 2005 by David M. Gay
+All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and its
+documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and that
+both that the copyright notice and this permission notice and warranty
+disclaimer appear in supporting documentation, and that the name of
+the author or any of his current or former employers not be used in
+advertising or publicity pertaining to distribution of the software
+without specific, written prior permission.
+
+THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN
+NO EVENT SHALL THE AUTHOR OR ANY OF HIS CURRENT OR FORMER EMPLOYERS BE
+LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
+DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+SOFTWARE.
+
+****************************************************************/
+
+/* Please send bug reports to David M. Gay (dmg at acm dot org,
+ * with " at " changed at "@" and " dot " changed to ".").	*/
+
+/* Program to compute quiet NaNs of various precisions (float,	*/
+/* double, and perhaps long double) on the current system,	*/
+/* provided the system uses binary IEEE (P754) arithmetic.	*/
+/* Note that one system's quiet NaN may be a signaling NaN on	*/
+/* another system.  The IEEE arithmetic standards (P754, P854)	*/
+/* do not specify how to distinguish signaling NaNs from quiet	*/
+/* ones, and this detail varies across systems.	 The computed	*/
+/* NaN values are encoded in #defines for values for an		*/
+/* unsigned 32-bit integer type, called Ulong below, and	*/
+/* (for long double) perhaps as unsigned short values.  Once	*/
+/* upon a time, there were PC compilers for Intel CPUs that	*/
+/* had sizeof(long double) = 10.  Are such compilers still	*/
+/* distributed?							*/
+
+#include <stdio.h>
+#include "arith.h"
+
+#ifndef Long
+#define Long long
+#endif
+
+typedef unsigned Long Ulong;
+
+#undef HAVE_IEEE
+#ifdef IEEE_8087
+#define _0 1
+#define _1 0
+#define HAVE_IEEE
+#endif
+#ifdef IEEE_MC68k
+#define _0 0
+#define _1 1
+#define HAVE_IEEE
+#endif
+
+#define UL (unsigned long)
+
+ int
+main(void)
+{
+#ifdef HAVE_IEEE
+	typedef union {
+		float f;
+		double d;
+		Ulong L[4];
+#ifndef NO_LONG_LONG
+		unsigned short u[5];
+		long double D;
+#endif
+		} U;
+	U a, b, c;
+	int i;
+
+	a.L[0] = b.L[0] = 0x7f800000;
+	c.f = a.f - b.f;
+	printf("#define f_QNAN 0x%lx\n", UL c.L[0]);
+	a.L[_0] = b.L[_0] = 0x7ff00000;
+	a.L[_1] = b.L[_1] = 0;
+	c.d = a.d - b.d;	/* quiet NaN */
+	printf("#define d_QNAN0 0x%lx\n", UL c.L[0]);
+	printf("#define d_QNAN1 0x%lx\n", UL c.L[1]);
+#ifdef NO_LONG_LONG
+	for(i = 0; i < 4; i++)
+		printf("#define ld_QNAN%d 0xffffffff\n", i);
+	for(i = 0; i < 5; i++)
+		printf("#define ldus_QNAN%d 0xffff\n", i);
+#else
+	b.D = c.D = a.d;
+	if (printf("") < 0)
+		c.D = 37;	/* never executed; just defeat optimization */
+	a.L[2] = a.L[3] = 0;
+	a.D = b.D - c.D;
+	for(i = 0; i < 4; i++)
+		printf("#define ld_QNAN%d 0x%lx\n", i, UL a.L[i]);
+	for(i = 0; i < 5; i++)
+		printf("#define ldus_QNAN%d 0x%x\n", i, a.u[i]);
+#endif
+#endif /* HAVE_IEEE */
+	return 0;
+	}
-- 
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