693 Opensource replacement of sunwlibm

Reviewed by: Igor Kozhukhov ikozhukhov@gmail.com
Reviewed by: Keith M Wesolowski <keith.wesolowski@joyent.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Dan McDonald <danmcd@omniti.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/usr/src/lib/libm/common/m9x/fmax.c b/usr/src/lib/libm/common/m9x/fmax.c
new file mode 100644
index 0000000000..f9a66d45d1
--- /dev/null
+++ b/usr/src/lib/libm/common/m9x/fmax.c
@@ -0,0 +1,81 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ */
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#if defined(ELFOBJ)
+#pragma weak fmax = __fmax
+#endif
+
+/*
+ * fmax(x,y) returns the larger of x and y.  If just one of the
+ * arguments is NaN, fmax returns the other argument.  If both
+ * arguments are NaN, fmax returns NaN.
+ *
+ * See fmaxf.c for a discussion of implementation trade-offs.
+ */
+
+#include "libm.h"	/* for isgreaterequal macro */
+#include <fenv.h>
+
+double
+__fmax(double x, double y) {
+	union {
+		unsigned i[2];
+		double d;
+	} xx, yy;
+	unsigned s;
+
+	/* if y is nan, replace it by x */
+	if (y != y)
+		y = x;
+
+	/* if x is nan, replace it by y */
+	if (x != x)
+		x = y;
+
+	/* At this point, x and y are either both numeric, or both NaN */
+	if (!isnan(x) && !isgreaterequal(x, y))
+		x = y;
+
+	/*
+	 * clear the sign of the result if either x or y has its sign clear
+	 */
+	xx.d = x;
+	yy.d = y;
+#if defined(__sparc)
+	s = ~(xx.i[0] & yy.i[0]) & 0x80000000;
+	xx.i[0] &= ~s;
+#elif defined(__x86)
+	s = ~(xx.i[1] & yy.i[1]) & 0x80000000;
+	xx.i[1] &= ~s;
+#else
+#error Unknown architecture
+#endif
+
+	return (xx.d);
+}