From 0ecb606cb6cf65de1d9fc8a919bceb4be476c602 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 12 Jul 2007 18:26:36 +0000
Subject: 2.5-18.1

---
 sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c | 109 ++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c

(limited to 'sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c')

diff --git a/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c b/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c
new file mode 100644
index 0000000..1f533ca
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128ibm/e_sqrtl.c
@@ -0,0 +1,109 @@
+/*
+ * IBM Accurate Mathematical Library
+ * written by International Business Machines Corp.
+ * Copyright (C) 2001, 2004, 2006 Free Software Foundation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+/*********************************************************************/
+/* MODULE_NAME: uroot.c                                              */
+/*                                                                   */
+/* FUNCTION:    usqrt                                                */
+/*                                                                   */
+/* FILES NEEDED: dla.h endian.h mydefs.h uroot.h                     */
+/*               uroot.tbl                                           */
+/*                                                                   */
+/* An ultimate sqrt routine. Given an IEEE double machine number x   */
+/* it computes the correctly rounded (to nearest) value of square    */
+/* root of x.                                                        */
+/* Assumption: Machine arithmetic operations are performed in        */
+/* round to nearest mode of IEEE 754 standard.                       */
+/*                                                                   */
+/*********************************************************************/
+
+#include <math_private.h>
+
+typedef unsigned int int4;
+typedef union {int4 i[4]; long double x; double d[2]; } mynumber;
+
+static const  mynumber
+  t512 = {{0x5ff00000, 0x00000000, 0x00000000, 0x00000000 }},  /* 2^512  */
+  tm256 = {{0x2ff00000, 0x00000000, 0x00000000, 0x00000000 }};  /* 2^-256 */
+static const double
+two54 = 1.80143985094819840000e+16, /* 0x4350000000000000 */
+twom54 = 5.55111512312578270212e-17; /* 0x3C90000000000000 */
+
+/*********************************************************************/
+/* An ultimate sqrt routine. Given an IEEE double machine number x   */
+/* it computes the correctly rounded (to nearest) value of square    */
+/* root of x.                                                        */
+/*********************************************************************/
+long double __ieee754_sqrtl(long double x) 
+{
+  static const long double big = 134217728.0, big1 = 134217729.0;
+  long double t,s,i;
+  mynumber a,c;
+  int4 k, l, m;
+  int n;
+  double d;
+
+  a.x=x;
+  k=a.i[0] & 0x7fffffff;
+  /*----------------- 2^-1022  <= | x |< 2^1024  -----------------*/
+  if (k>0x000fffff && k<0x7ff00000) {
+    if (x < 0) return (big1-big1)/(big-big);
+    l = (k&0x001fffff)|0x3fe00000;
+    if (((a.i[2] & 0x7fffffff) | a.i[3]) != 0) {
+      n = (int) ((l - k) * 2) >> 21;
+      m = (a.i[2] >> 20) & 0x7ff;
+      if (m == 0) {
+	a.d[1] *= two54;
+	m = ((a.i[2] >> 20) & 0x7ff) - 54;
+      }
+      m += n;
+      if (m > 0)
+	a.i[2] = (a.i[2] & 0x800fffff) | (m << 20);
+      else if (m <= -54) {
+	a.i[2] &= 0x80000000;
+	a.i[3] = 0;
+      } else {
+	m += 54;
+	a.i[2] = (a.i[2] & 0x800fffff) | (m << 20);
+	a.d[1] *= twom54;
+      }
+    }
+    a.i[0] = l;
+    s = a.x;
+    d = __ieee754_sqrt (a.d[0]);
+    c.i[0] = 0x20000000+((k&0x7fe00000)>>1);
+    c.i[1] = 0;
+    c.i[2] = 0;
+    c.i[3] = 0;
+    i = d;
+    t = 0.5L * (i + s / i);
+    i = 0.5L * (t + s / t);
+    return c.x * i;
+  }
+  else {
+    if (k>=0x7ff00000) {
+      if (a.i[0] == 0xfff00000 && a.i[1] == 0)
+	return (big1-big1)/(big-big); /* sqrt (-Inf) = NaN.  */
+      return x; /* sqrt (NaN) = NaN, sqrt (+Inf) = +Inf.  */
+    }
+    if (x == 0) return x;
+    if (x < 0) return (big1-big1)/(big-big);
+    return tm256.x*__ieee754_sqrtl(x*t512.x);
+  }
+}
-- 
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