Add functions for converting to and from binary16 half-precision floating point values. Derived from http://mvn.io7m.com/ieee754b16, of which I am the original author.

1 files changed, 116 insertions, 0 deletions

diff --git a/src/jogl/classes/com/jogamp/opengl/math/Binary64.java b/src/jogl/classes/com/jogamp/opengl/math/Binary64.java
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+++ b/src/jogl/classes/com/jogamp/opengl/math/Binary64.java
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+/**
+ * Copyright 2013 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+
+package com.jogamp.opengl.math;
+
+/**
+ * Functions for interrogating <code>binary64</code> (double) values.
+ */
+
+public final class Binary64
+{
+  static final long NEGATIVE_ZERO_BITS;
+  static final long MASK_SIGN;
+  static final long MASK_EXPONENT;
+  static final long MASK_SIGNIFICAND;
+  static final long BIAS;
+
+  static {
+    NEGATIVE_ZERO_BITS = 0x8000000000000000L;
+    MASK_SIGN = 0x8000000000000000L;
+    MASK_EXPONENT = 0x7ff0000000000000L;
+    MASK_SIGNIFICAND = 0x000fffffffffffffL;
+    BIAS = 1023;
+  }
+
+  /**
+   * <p>
+   * Extract and unbias the exponent of the given packed <code>double</code>
+   * value.
+   * </p>
+   * <p>
+   * The exponent is encoded <i>biased</i> as a number in the range
+   * <code>[0, 2047]</code>, with <code>0</code> indicating that the number is
+   * <i>subnormal</i> and <code>[1, 2046]</code> denoting the actual exponent
+   * plus {@link #BIAS}. Infinite and <code>NaN</code> values always have a
+   * biased exponent of <code>2047</code>.
+   * </p>
+   * <p>
+   * This function will therefore return:
+   * </p>
+   * <ul>
+   * <li>
+   * <code>0 - {@link #BIAS} = -1023</code> iff the input is a
+   * <i>subnormal</i> number.</li>
+   * <li>An integer in the range
+   * <code>[1 - {@link #BIAS}, 2046 - {@link #BIAS}] = [-1022, 1023]</code>
+   * iff the input is a <i>normal</i> number.</li>
+   * <li>
+   * <code>2047 - {@link #BIAS} = 1024</code> iff the input is
+   * {@link #POSITIVE_INFINITY}, {@link #NEGATIVE_INFINITY}, or
+   * <code>NaN</code>.</li>
+   * </ul>
+   * 
+   * @see #packSetExponentUnbiasedUnchecked(int)
+   */
+
+  public static long unpackGetExponentUnbiased(
+    final double d)
+  {
+    final long b = Double.doubleToRawLongBits(d);
+    final long em = b & Binary64.MASK_EXPONENT;
+    final long es = em >> 52;
+    return es - Binary64.BIAS;
+  }
+
+  /**
+   * <p>
+   * Return the significand of the given double value.
+   * </p>
+   */
+  
+  public static long unpackGetSignificand(
+    final double d)
+  {
+    final long b = Double.doubleToRawLongBits(d);
+    return b & Binary64.MASK_SIGNIFICAND;
+  }
+
+  /**
+   * <p>
+   * Return the sign of the given double value.
+   * </p>
+   */
+  
+  public static long unpackGetSign(
+    final double d)
+  {
+    final long b = Double.doubleToRawLongBits(d);
+    return ((b & Binary64.MASK_SIGN) >> 63) & 1;
+  }
+}