changeset 15463:0cd4b4def24f

8164524: Correct inconsistencies in floating-point abs spec Reviewed-by: martin, bpb
author darcy
date Mon, 22 Aug 2016 17:22:09 -0700
parents 7925851df5ff
children eeef9a64af04
files src/java.base/share/classes/java/lang/Math.java src/java.base/share/classes/java/lang/StrictMath.java
diffstat 2 files changed, 28 insertions(+), 8 deletions(-) [+]
line wrap: on
line diff
--- a/src/java.base/share/classes/java/lang/Math.java	Mon Aug 22 15:27:50 2016 -0700
+++ b/src/java.base/share/classes/java/lang/Math.java	Mon Aug 22 17:22:09 2016 -0700
@@ -1370,8 +1370,13 @@
      * result is positive zero.
      * <li>If the argument is infinite, the result is positive infinity.
      * <li>If the argument is NaN, the result is NaN.</ul>
-     * In other words, the result is the same as the value of the expression:
-     * <p>{@code Float.intBitsToFloat(0x7fffffff & Float.floatToIntBits(a))}
+     *
+     * @apiNote As implied by the above, one valid implementation of
+     * this method is given by the expression below which computes a
+     * {@code float} with the same exponent and significand as the
+     * argument but with a guaranteed zero sign bit indicating a
+     * positive value:<br>
+     * {@code Float.intBitsToFloat(0x7fffffff & Float.floatToRawIntBits(a))}
      *
      * @param   a   the argument whose absolute value is to be determined
      * @return  the absolute value of the argument.
@@ -1389,8 +1394,13 @@
      * is positive zero.
      * <li>If the argument is infinite, the result is positive infinity.
      * <li>If the argument is NaN, the result is NaN.</ul>
-     * In other words, the result is the same as the value of the expression:
-     * <p>{@code Double.longBitsToDouble((Double.doubleToLongBits(a)<<1)>>>1)}
+     *
+     * @apiNote As implied by the above, one valid implementation of
+     * this method is given by the expression below which computes a
+     * {@code double} with the same exponent and significand as the
+     * argument but with a guaranteed zero sign bit indicating a
+     * positive value:<br>
+     * {@code Double.longBitsToDouble((Double.doubleToRawLongBits(a)<<1)>>>1)}
      *
      * @param   a   the argument whose absolute value is to be determined
      * @return  the absolute value of the argument.
--- a/src/java.base/share/classes/java/lang/StrictMath.java	Mon Aug 22 15:27:50 2016 -0700
+++ b/src/java.base/share/classes/java/lang/StrictMath.java	Mon Aug 22 17:22:09 2016 -0700
@@ -1070,8 +1070,13 @@
      * result is positive zero.
      * <li>If the argument is infinite, the result is positive infinity.
      * <li>If the argument is NaN, the result is NaN.</ul>
-     * In other words, the result is the same as the value of the expression:
-     * <p>{@code Float.intBitsToFloat(0x7fffffff & Float.floatToIntBits(a))}
+     *
+     * @apiNote As implied by the above, one valid implementation of
+     * this method is given by the expression below which computes a
+     * {@code float} with the same exponent and significand as the
+     * argument but with a guaranteed zero sign bit indicating a
+     * positive value: <br>
+     * {@code Float.intBitsToFloat(0x7fffffff & Float.floatToRawIntBits(a))}
      *
      * @param   a   the argument whose absolute value is to be determined
      * @return  the absolute value of the argument.
@@ -1089,8 +1094,13 @@
      * is positive zero.
      * <li>If the argument is infinite, the result is positive infinity.
      * <li>If the argument is NaN, the result is NaN.</ul>
-     * In other words, the result is the same as the value of the expression:
-     * <p>{@code Double.longBitsToDouble((Double.doubleToLongBits(a)<<1)>>>1)}
+     *
+     * @apiNote As implied by the above, one valid implementation of
+     * this method is given by the expression below which computes a
+     * {@code double} with the same exponent and significand as the
+     * argument but with a guaranteed zero sign bit indicating a
+     * positive value: <br>
+     * {@code Double.longBitsToDouble((Double.doubleToRawLongBits(a)<<1)>>>1)}
      *
      * @param   a   the argument whose absolute value is to be determined
      * @return  the absolute value of the argument.