src/share/classes/sun/misc/FpUtils.java
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@@ -1,7 +1,7 @@
/*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, 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
@@ -123,65 +123,34 @@
/**
* Don't let anyone instantiate this class.
*/
private FpUtils() {}
- // Constants used in scalb
- static double twoToTheDoubleScaleUp = powerOfTwoD(512);
- static double twoToTheDoubleScaleDown = powerOfTwoD(-512);
-
// Helper Methods
// The following helper methods are used in the implementation of
// the public recommended functions; they generally omit certain
// tests for exception cases.
/**
* Returns unbiased exponent of a {@code double}.
+ * @deprecated Use Math.getExponent.
*/
+ @Deprecated
public static int getExponent(double d){
- /*
- * Bitwise convert d to long, mask out exponent bits, shift
- * to the right and then subtract out double's bias adjust to
- * get true exponent value.
- */
- return (int)(((Double.doubleToRawLongBits(d) & DoubleConsts.EXP_BIT_MASK) >>
- (DoubleConsts.SIGNIFICAND_WIDTH - 1)) - DoubleConsts.EXP_BIAS);
+ return Math.getExponent(d);
}
/**
* Returns unbiased exponent of a {@code float}.
+ * @deprecated Use Math.getExponent.
*/
+ @Deprecated
public static int getExponent(float f){
- /*
- * Bitwise convert f to integer, mask out exponent bits, shift
- * to the right and then subtract out float's bias adjust to
- * get true exponent value
- */
- return ((Float.floatToRawIntBits(f) & FloatConsts.EXP_BIT_MASK) >>
- (FloatConsts.SIGNIFICAND_WIDTH - 1)) - FloatConsts.EXP_BIAS;
+ return Math.getExponent(f);
}
- /**
- * Returns a floating-point power of two in the normal range.
- */
- static double powerOfTwoD(int n) {
- assert(n >= DoubleConsts.MIN_EXPONENT && n <= DoubleConsts.MAX_EXPONENT);
- return Double.longBitsToDouble((((long)n + (long)DoubleConsts.EXP_BIAS) <<
- (DoubleConsts.SIGNIFICAND_WIDTH-1))
- & DoubleConsts.EXP_BIT_MASK);
- }
-
- /**
- * Returns a floating-point power of two in the normal range.
- */
- static float powerOfTwoF(int n) {
- assert(n >= FloatConsts.MIN_EXPONENT && n <= FloatConsts.MAX_EXPONENT);
- return Float.intBitsToFloat(((n + FloatConsts.EXP_BIAS) <<
- (FloatConsts.SIGNIFICAND_WIDTH-1))
- & FloatConsts.EXP_BIT_MASK);
- }
/**
* Returns the first floating-point argument with the sign of the
* second floating-point argument. Note that unlike the {@link
* FpUtils#copySign(double, double) copySign} method, this method
@@ -193,17 +162,15 @@
* @param magnitude the parameter providing the magnitude of the result
* @param sign the parameter providing the sign of the result
* @return a value with the magnitude of {@code magnitude}
* and the sign of {@code sign}.
* @author Joseph D. Darcy
+ * @deprecated Use Math.copySign.
*/
+ @Deprecated
public static double rawCopySign(double magnitude, double sign) {
- return Double.longBitsToDouble((Double.doubleToRawLongBits(sign) &
- (DoubleConsts.SIGN_BIT_MASK)) |
- (Double.doubleToRawLongBits(magnitude) &
- (DoubleConsts.EXP_BIT_MASK |
- DoubleConsts.SIGNIF_BIT_MASK)));
+ return Math.copySign(magnitude, sign);
}
/**
* Returns the first floating-point argument with the sign of the
* second floating-point argument. Note that unlike the {@link
@@ -216,17 +183,15 @@
* @param magnitude the parameter providing the magnitude of the result
* @param sign the parameter providing the sign of the result
* @return a value with the magnitude of {@code magnitude}
* and the sign of {@code sign}.
* @author Joseph D. Darcy
+ * @deprecated Use Math.copySign.
*/
+ @Deprecated
public static float rawCopySign(float magnitude, float sign) {
- return Float.intBitsToFloat((Float.floatToRawIntBits(sign) &
- (FloatConsts.SIGN_BIT_MASK)) |
- (Float.floatToRawIntBits(magnitude) &
- (FloatConsts.EXP_BIT_MASK |
- FloatConsts.SIGNIF_BIT_MASK)));
+ return Math.copySign(magnitude, sign);
}
/* ***************************************************************** */
/**
@@ -556,86 +521,15 @@
*
* @param d number to be scaled by a power of two.
* @param scale_factor power of 2 used to scale {@code d}
* @return {@code d * }2<sup>{@code scale_factor}</sup>
* @author Joseph D. Darcy
+ * @deprecated Use Math.scalb.
*/
+ @Deprecated
public static double scalb(double d, int scale_factor) {
- /*
- * This method does not need to be declared strictfp to
- * compute the same correct result on all platforms. When
- * scaling up, it does not matter what order the
- * multiply-store operations are done; the result will be
- * finite or overflow regardless of the operation ordering.
- * However, to get the correct result when scaling down, a
- * particular ordering must be used.
- *
- * When scaling down, the multiply-store operations are
- * sequenced so that it is not possible for two consecutive
- * multiply-stores to return subnormal results. If one
- * multiply-store result is subnormal, the next multiply will
- * round it away to zero. This is done by first multiplying
- * by 2 ^ (scale_factor % n) and then multiplying several
- * times by by 2^n as needed where n is the exponent of number
- * that is a covenient power of two. In this way, at most one
- * real rounding error occurs. If the double value set is
- * being used exclusively, the rounding will occur on a
- * multiply. If the double-extended-exponent value set is
- * being used, the products will (perhaps) be exact but the
- * stores to d are guaranteed to round to the double value
- * set.
- *
- * It is _not_ a valid implementation to first multiply d by
- * 2^MIN_EXPONENT and then by 2 ^ (scale_factor %
- * MIN_EXPONENT) since even in a strictfp program double
- * rounding on underflow could occur; e.g. if the scale_factor
- * argument was (MIN_EXPONENT - n) and the exponent of d was a
- * little less than -(MIN_EXPONENT - n), meaning the final
- * result would be subnormal.
- *
- * Since exact reproducibility of this method can be achieved
- * without any undue performance burden, there is no
- * compelling reason to allow double rounding on underflow in
- * scalb.
- */
-
- // magnitude of a power of two so large that scaling a finite
- // nonzero value by it would be guaranteed to over or
- // underflow; due to rounding, scaling down takes takes an
- // additional power of two which is reflected here
- final int MAX_SCALE = DoubleConsts.MAX_EXPONENT + -DoubleConsts.MIN_EXPONENT +
- DoubleConsts.SIGNIFICAND_WIDTH + 1;
- int exp_adjust = 0;
- int scale_increment = 0;
- double exp_delta = Double.NaN;
-
- // Make sure scaling factor is in a reasonable range
-
- if(scale_factor < 0) {
- scale_factor = Math.max(scale_factor, -MAX_SCALE);
- scale_increment = -512;
- exp_delta = twoToTheDoubleScaleDown;
- }
- else {
- scale_factor = Math.min(scale_factor, MAX_SCALE);
- scale_increment = 512;
- exp_delta = twoToTheDoubleScaleUp;
- }
-
- // Calculate (scale_factor % +/-512), 512 = 2^9, using
- // technique from "Hacker's Delight" section 10-2.
- int t = (scale_factor >> 9-1) >>> 32 - 9;
- exp_adjust = ((scale_factor + t) & (512 -1)) - t;
-
- d *= powerOfTwoD(exp_adjust);
- scale_factor -= exp_adjust;
-
- while(scale_factor != 0) {
- d *= exp_delta;
- scale_factor -= scale_increment;
- }
- return d;
+ return Math.scalb(d, scale_factor);
}
/**
* Return {@code f} ×
* 2<sup>{@code scale_factor}</sup> rounded as if performed
@@ -665,32 +559,15 @@
*
* @param f number to be scaled by a power of two.
* @param scale_factor power of 2 used to scale {@code f}
* @return {@code f * }2<sup>{@code scale_factor}</sup>
* @author Joseph D. Darcy
+ * @deprecated Use Math.scalb.
*/
+ @Deprecated
public static float scalb(float f, int scale_factor) {
- // magnitude of a power of two so large that scaling a finite
- // nonzero value by it would be guaranteed to over or
- // underflow; due to rounding, scaling down takes takes an
- // additional power of two which is reflected here
- final int MAX_SCALE = FloatConsts.MAX_EXPONENT + -FloatConsts.MIN_EXPONENT +
- FloatConsts.SIGNIFICAND_WIDTH + 1;
-
- // Make sure scaling factor is in a reasonable range
- scale_factor = Math.max(Math.min(scale_factor, MAX_SCALE), -MAX_SCALE);
-
- /*
- * Since + MAX_SCALE for float fits well within the double
- * exponent range and + float -> double conversion is exact
- * the multiplication below will be exact. Therefore, the
- * rounding that occurs when the double product is cast to
- * float will be the correctly rounded float result. Since
- * all operations other than the final multiply will be exact,
- * it is not necessary to declare this method strictfp.
- */
- return (float)((double)f*powerOfTwoD(scale_factor));
+ return Math.scalb(f, scale_factor);
}
/**
* Returns the floating-point number adjacent to the first
* argument in the direction of the second argument. If both
@@ -728,69 +605,15 @@
* {@code start}'s neighbors or {@code start} should
* be returned
* @return The floating-point number adjacent to {@code start} in the
* direction of {@code direction}.
* @author Joseph D. Darcy
+ * @deprecated Use Math.nextAfter
*/
+ @Deprecated
public static double nextAfter(double start, double direction) {
- /*
- * The cases:
- *
- * nextAfter(+infinity, 0) == MAX_VALUE
- * nextAfter(+infinity, +infinity) == +infinity
- * nextAfter(-infinity, 0) == -MAX_VALUE
- * nextAfter(-infinity, -infinity) == -infinity
- *
- * are naturally handled without any additional testing
- */
-
- // First check for NaN values
- if (isNaN(start) || isNaN(direction)) {
- // return a NaN derived from the input NaN(s)
- return start + direction;
- } else if (start == direction) {
- return direction;
- } else { // start > direction or start < direction
- // Add +0.0 to get rid of a -0.0 (+0.0 + -0.0 => +0.0)
- // then bitwise convert start to integer.
- long transducer = Double.doubleToRawLongBits(start + 0.0d);
-
- /*
- * IEEE 754 floating-point numbers are lexicographically
- * ordered if treated as signed- magnitude integers .
- * Since Java's integers are two's complement,
- * incrementing" the two's complement representation of a
- * logically negative floating-point value *decrements*
- * the signed-magnitude representation. Therefore, when
- * the integer representation of a floating-point values
- * is less than zero, the adjustment to the representation
- * is in the opposite direction than would be expected at
- * first .
- */
- if (direction > start) { // Calculate next greater value
- transducer = transducer + (transducer >= 0L ? 1L:-1L);
- } else { // Calculate next lesser value
- assert direction < start;
- if (transducer > 0L)
- --transducer;
- else
- if (transducer < 0L )
- ++transducer;
- /*
- * transducer==0, the result is -MIN_VALUE
- *
- * The transition from zero (implicitly
- * positive) to the smallest negative
- * signed magnitude value must be done
- * explicitly.
- */
- else
- transducer = DoubleConsts.SIGN_BIT_MASK | 1L;
- }
-
- return Double.longBitsToDouble(transducer);
- }
+ return Math.nextAfter(start, direction);
}
/**
* Returns the floating-point number adjacent to the first
* argument in the direction of the second argument. If both
@@ -828,69 +651,15 @@
* {@code start}'s neighbors or {@code start} should
* be returned
* @return The floating-point number adjacent to {@code start} in the
* direction of {@code direction}.
* @author Joseph D. Darcy
+ * @deprecated Use Math.nextAfter.
*/
+ @Deprecated
public static float nextAfter(float start, double direction) {
- /*
- * The cases:
- *
- * nextAfter(+infinity, 0) == MAX_VALUE
- * nextAfter(+infinity, +infinity) == +infinity
- * nextAfter(-infinity, 0) == -MAX_VALUE
- * nextAfter(-infinity, -infinity) == -infinity
- *
- * are naturally handled without any additional testing
- */
-
- // First check for NaN values
- if (isNaN(start) || isNaN(direction)) {
- // return a NaN derived from the input NaN(s)
- return start + (float)direction;
- } else if (start == direction) {
- return (float)direction;
- } else { // start > direction or start < direction
- // Add +0.0 to get rid of a -0.0 (+0.0 + -0.0 => +0.0)
- // then bitwise convert start to integer.
- int transducer = Float.floatToRawIntBits(start + 0.0f);
-
- /*
- * IEEE 754 floating-point numbers are lexicographically
- * ordered if treated as signed- magnitude integers .
- * Since Java's integers are two's complement,
- * incrementing" the two's complement representation of a
- * logically negative floating-point value *decrements*
- * the signed-magnitude representation. Therefore, when
- * the integer representation of a floating-point values
- * is less than zero, the adjustment to the representation
- * is in the opposite direction than would be expected at
- * first.
- */
- if (direction > start) {// Calculate next greater value
- transducer = transducer + (transducer >= 0 ? 1:-1);
- } else { // Calculate next lesser value
- assert direction < start;
- if (transducer > 0)
- --transducer;
- else
- if (transducer < 0 )
- ++transducer;
- /*
- * transducer==0, the result is -MIN_VALUE
- *
- * The transition from zero (implicitly
- * positive) to the smallest negative
- * signed magnitude value must be done
- * explicitly.
- */
- else
- transducer = FloatConsts.SIGN_BIT_MASK | 1;
- }
-
- return Float.intBitsToFloat(transducer);
- }
+ return Math.nextAfter(start, direction);
}
/**
* Returns the floating-point value adjacent to {@code d} in
* the direction of positive infinity. This method is
@@ -913,19 +682,15 @@
*
* @param d starting floating-point value
* @return The adjacent floating-point value closer to positive
* infinity.
* @author Joseph D. Darcy
+ * @deprecated use Math.nextUp.
*/
+ @Deprecated
public static double nextUp(double d) {
- if( isNaN(d) || d == Double.POSITIVE_INFINITY)
- return d;
- else {
- d += 0.0d;
- return Double.longBitsToDouble(Double.doubleToRawLongBits(d) +
- ((d >= 0.0d)?+1L:-1L));
- }
+ return Math.nextUp(d);
}
/**
* Returns the floating-point value adjacent to {@code f} in
* the direction of positive infinity. This method is
@@ -948,19 +713,15 @@
*
* @param f starting floating-point value
* @return The adjacent floating-point value closer to positive
* infinity.
* @author Joseph D. Darcy
+ * @deprecated Use Math.nextUp.
*/
+ @Deprecated
public static float nextUp(float f) {
- if( isNaN(f) || f == FloatConsts.POSITIVE_INFINITY)
- return f;
- else {
- f += 0.0f;
- return Float.intBitsToFloat(Float.floatToRawIntBits(f) +
- ((f >= 0.0f)?+1:-1));
- }
+ return Math.nextUp(f);
}
/**
* Returns the floating-point value adjacent to {@code d} in
* the direction of negative infinity. This method is
@@ -1045,13 +806,15 @@
* @param sign the parameter providing the sign of the result
* @return a value with the magnitude of {@code magnitude}
* and the sign of {@code sign}.
* @author Joseph D. Darcy
* @since 1.5
+ * @deprecated Use StrictMath.copySign.
*/
+ @Deprecated
public static double copySign(double magnitude, double sign) {
- return rawCopySign(magnitude, (isNaN(sign)?1.0d:sign));
+ return StrictMath.copySign(magnitude, sign);
}
/**
* Returns the first floating-point argument with the sign of the
* second floating-point argument. For this method, a NaN
@@ -1061,13 +824,15 @@
* @param magnitude the parameter providing the magnitude of the result
* @param sign the parameter providing the sign of the result
* @return a value with the magnitude of {@code magnitude}
* and the sign of {@code sign}.
* @author Joseph D. Darcy
+ * @deprecated Use StrictMath.copySign.
*/
+ @Deprecated
public static float copySign(float magnitude, float sign) {
- return rawCopySign(magnitude, (isNaN(sign)?1.0f:sign));
+ return StrictMath.copySign(magnitude, sign);
}
/**
* Returns the size of an ulp of the argument. An ulp of a
* {@code double} value is the positive distance between this
@@ -1088,37 +853,15 @@
*
* @param d the floating-point value whose ulp is to be returned
* @return the size of an ulp of the argument
* @author Joseph D. Darcy
* @since 1.5
+ * @deprecated Use Math.ulp.
*/
+ @Deprecated
public static double ulp(double d) {
- int exp = getExponent(d);
-
- switch(exp) {
- case DoubleConsts.MAX_EXPONENT+1: // NaN or infinity
- return Math.abs(d);
-
- case DoubleConsts.MIN_EXPONENT-1: // zero or subnormal
- return Double.MIN_VALUE;
-
- default:
- assert exp <= DoubleConsts.MAX_EXPONENT && exp >= DoubleConsts.MIN_EXPONENT;
-
- // ulp(x) is usually 2^(SIGNIFICAND_WIDTH-1)*(2^ilogb(x))
- exp = exp - (DoubleConsts.SIGNIFICAND_WIDTH-1);
- if (exp >= DoubleConsts.MIN_EXPONENT) {
- return powerOfTwoD(exp);
- }
- else {
- // return a subnormal result; left shift integer
- // representation of Double.MIN_VALUE appropriate
- // number of positions
- return Double.longBitsToDouble(1L <<
- (exp - (DoubleConsts.MIN_EXPONENT - (DoubleConsts.SIGNIFICAND_WIDTH-1)) ));
- }
- }
+ return Math.ulp(d);
}
/**
* Returns the size of an ulp of the argument. An ulp of a
* {@code float} value is the positive distance between this
@@ -1139,37 +882,15 @@
*
* @param f the floating-point value whose ulp is to be returned
* @return the size of an ulp of the argument
* @author Joseph D. Darcy
* @since 1.5
+ * @deprecated Use Math.ulp.
*/
+ @Deprecated
public static float ulp(float f) {
- int exp = getExponent(f);
-
- switch(exp) {
- case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
- return Math.abs(f);
-
- case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
- return FloatConsts.MIN_VALUE;
-
- default:
- assert exp <= FloatConsts.MAX_EXPONENT && exp >= FloatConsts.MIN_EXPONENT;
-
- // ulp(x) is usually 2^(SIGNIFICAND_WIDTH-1)*(2^ilogb(x))
- exp = exp - (FloatConsts.SIGNIFICAND_WIDTH-1);
- if (exp >= FloatConsts.MIN_EXPONENT) {
- return powerOfTwoF(exp);
- }
- else {
- // return a subnormal result; left shift integer
- // representation of FloatConsts.MIN_VALUE appropriate
- // number of positions
- return Float.intBitsToFloat(1 <<
- (exp - (FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1)) ));
- }
- }
+ return Math.ulp(f);
}
/**
* Returns the signum function of the argument; zero if the argument
* is zero, 1.0 if the argument is greater than zero, -1.0 if the
@@ -1184,13 +905,15 @@
*
* @param d the floating-point value whose signum is to be returned
* @return the signum function of the argument
* @author Joseph D. Darcy
* @since 1.5
+ * @deprecated Use Math.signum.
*/
+ @Deprecated
public static double signum(double d) {
- return (d == 0.0 || isNaN(d))?d:copySign(1.0, d);
+ return Math.signum(d);
}
/**
* Returns the signum function of the argument; zero if the argument
* is zero, 1.0f if the argument is greater than zero, -1.0f if the
@@ -1205,11 +928,12 @@
*
* @param f the floating-point value whose signum is to be returned
* @return the signum function of the argument
* @author Joseph D. Darcy
* @since 1.5
+ * @deprecated Use Math.signum.
*/
+ @Deprecated
public static float signum(float f) {
- return (f == 0.0f || isNaN(f))?f:copySign(1.0f, f);
+ return Math.signum(f);
}
-
}