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, 109 insertions, 0 deletions

diff --git a/usr/src/lib/libm/common/R/sqrtf.c b/usr/src/lib/libm/common/R/sqrtf.c
new file mode 100644
index 0000000000..125fd4b03d
--- /dev/null
+++ b/usr/src/lib/libm/common/R/sqrtf.c
@@ -0,0 +1,109 @@
+/*
+ * 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 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma weak sqrtf = __sqrtf
+
+#include "libm.h"
+
+#ifdef __INLINE
+
+extern float __inline_sqrtf(float);
+
+float
+sqrtf(float x) {
+	return (__inline_sqrtf(x));
+}
+
+#else	/* defined(__INLINE) */
+
+static const float huge = 1.0e35F, tiny = 1.0e-35F, zero = 0.0f;
+
+float
+sqrtf(float x) {
+	float	dz, w;
+	int 	*pw = (int *)&w;
+	int	ix, j, r, q, m, n, s, t;
+
+	w = x;
+	ix = pw[0];
+	if (ix <= 0) {
+		/* x is <= 0 or nan */
+		j = ix & 0x7fffffff;
+		if (j == 0)
+			return (w);
+		return ((w * zero) / zero);
+	}
+
+	if ((ix & 0x7f800000) == 0x7f800000) {
+		/* x is +inf or nan */
+		return (w * w);
+	}
+
+	m = ir_ilogb_(&w);
+	n = -m;
+	w = r_scalbn_(&w, (int *)&n);
+	ix = (pw[0] & 0x007fffff) | 0x00800000;
+	n = m / 2;
+	if ((n + n) != m) {
+		ix = ix + ix;
+		m -= 1;
+		n = m / 2;
+	}
+
+	/* generate sqrt(x) bit by bit */
+	ix <<= 1;
+	q = s = 0;
+	r = 0x01000000;
+	for (j = 1; j <= 25; j++) {
+		t = s + r;
+		if (t <= ix) {
+			s = t + r;
+			ix -= t;
+			q += r;
+		}
+		ix <<= 1;
+		r >>= 1;
+	}
+	if (ix == 0)
+		goto done;
+
+	/* raise inexact and determine the ambient rounding mode */
+	dz = huge - tiny;
+	if (dz < huge)
+		goto done;
+	dz = huge + tiny;
+	if (dz > huge)
+		q += 1;
+	q += (q & 1);
+
+done:
+	pw[0] = (q >> 1) + 0x3f000000;
+	return (r_scalbn_(&w, (int *)&n));
+}
+
+#endif	/* defined(__INLINE) */