jdk-sandbox: comparison jdk/test/java/lang/StrictMath/FdlibmTranslit.java

equal deleted inserted replaced

-:8392405ab038
+:a3f03999ed62
+/*
+* Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.  Oracle designates this
+* particular file as subject to the "Classpath" exception as provided
+* by Oracle in the LICENSE file that accompanied this code.
+*
+* This code 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 General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*/
+/**
+* A transliteration of the "Freely Distributable Math Library"
+* algorithms from C into Java. That is, this port of the algorithms
+* is as close to the C originals as possible while still being
+* readable legal Java.
+*/
+public class FdlibmTranslit {
+private FdlibmTranslit() {
+throw new UnsupportedOperationException("No FdLibmTranslit instances for you.");
+}
+/**
+* Return the low-order 32 bits of the double argument as an int.
+*/
+private static int __LO(double x) {
+long transducer = Double.doubleToRawLongBits(x);
+return (int)transducer;
+}
+/**
+* Return a double with its low-order bits of the second argument
+* and the high-order bits of the first argument..
+*/
+private static double __LO(double x, int low) {
+long transX = Double.doubleToRawLongBits(x);
+return Double.longBitsToDouble((transX & 0xFFFF_FFFF_0000_0000L)|low );
+}
+/**
+* Return the high-order 32 bits of the double argument as an int.
+*/
+private static int __HI(double x) {
+long transducer = Double.doubleToRawLongBits(x);
+return (int)(transducer >> 32);
+}
+/**
+* Return a double with its high-order bits of the second argument
+* and the low-order bits of the first argument..
+*/
+private static double __HI(double x, int high) {
+long transX = Double.doubleToRawLongBits(x);
+return Double.longBitsToDouble((transX & 0x0000_0000_FFFF_FFFFL)|( ((long)high)) << 32 );
+}
+public static double hypot(double x, double y) {
+return Hypot.compute(x, y);
+}
+/**
+* hypot(x,y)
+*
+* Method :
+*      If (assume round-to-nearest) z = x*x + y*y
+*      has error less than sqrt(2)/2 ulp, than
+*      sqrt(z) has error less than 1 ulp (exercise).
+*
+*      So, compute sqrt(x*x + y*y) with some care as
+*      follows to get the error below 1 ulp:
+*
+*      Assume x > y > 0;
+*      (if possible, set rounding to round-to-nearest)
+*      1. if x > 2y  use
+*              x1*x1 + (y*y + (x2*(x + x1))) for x*x + y*y
+*      where x1 = x with lower 32 bits cleared, x2 = x - x1; else
+*      2. if x <= 2y use
+*              t1*y1 + ((x-y) * (x-y) + (t1*y2 + t2*y))
+*      where t1 = 2x with lower 32 bits cleared, t2 = 2x - t1,
+*      y1= y with lower 32 bits chopped, y2 = y - y1.
+*
+*      NOTE: scaling may be necessary if some argument is too
+*            large or too tiny
+*
+* Special cases:
+*      hypot(x,y) is INF if x or y is +INF or -INF; else
+*      hypot(x,y) is NAN if x or y is NAN.
+*
+* Accuracy:
+*      hypot(x,y) returns sqrt(x^2 + y^2) with error less
+*      than 1 ulps (units in the last place)
+*/
+static class Hypot {
+public static double compute(double x, double y) {
+double a = x;
+double b = y;
+double t1, t2, y1, y2, w;
+int j, k, ha, hb;
+ha = __HI(x) & 0x7fffffff;        // high word of  x
+hb = __HI(y) & 0x7fffffff;        // high word of  y
+if(hb > ha) {
+a = y;
+b = x;
+j = ha;
+ha = hb;
+hb = j;
+} else {
+a = x;
+b = y;
+}
+a = __HI(a, ha);   // a <- |a|
+b = __HI(b, hb);   // b <- |b|
+if ((ha - hb) > 0x3c00000) {
+return a + b;  // x / y > 2**60
+}
+k=0;
+if (ha > 0x5f300000) {   // a>2**500
+if (ha >= 0x7ff00000) {       // Inf or NaN
+w = a + b;                // for sNaN
+if (((ha & 0xfffff) | __LO(a)) == 0)
+w = a;
+if (((hb ^ 0x7ff00000) | __LO(b)) == 0)
+w = b;
+return w;
+}
+// scale a and b by 2**-600
+ha -= 0x25800000;
+hb -= 0x25800000;
+k += 600;
+a = __HI(a, ha);
+b = __HI(b, hb);
+}
+if (hb < 0x20b00000) {   // b < 2**-500
+if (hb <= 0x000fffff) {      // subnormal b or 0 */
+if ((hb | (__LO(b))) == 0)
+return a;
+t1 = 0;
+t1 = __HI(t1, 0x7fd00000);  // t1=2^1022
+b *= t1;
+a *= t1;
+k -= 1022;
+} else {            // scale a and b by 2^600
+ha += 0x25800000;       // a *= 2^600
+hb += 0x25800000;       // b *= 2^600
+k -= 600;
+a = __HI(a, ha);
+b = __HI(b, hb);
+}
+}
+// medium size a and b
+w = a - b;
+if (w > b) {
+t1 = 0;
+t1 = __HI(t1, ha);
+t2 = a - t1;
+w  = Math.sqrt(t1*t1 - (b*(-b) - t2 * (a + t1)));
+} else {
+a  = a + a;
+y1 = 0;
+y1 = __HI(y1, hb);
+y2 = b - y1;
+t1 = 0;
+t1 = __HI(t1, ha + 0x00100000);
+t2 = a - t1;
+w  = Math.sqrt(t1*y1 - (w*(-w) - (t1*y2 + t2*b)));
+}
+if (k != 0) {
+t1 = 1.0;
+int t1_hi = __HI(t1);
+t1_hi += (k << 20);
+t1 = __HI(t1, t1_hi);
+return t1 * w;
+} else
+return w;
+}
+}
+}

changeset 32928	a3f03999ed62
child 32992	19ed8781c2ba