Java Code Examples for sun.misc.FloatConsts#SIGNIF_BIT_MASK
The following examples show how to use
sun.misc.FloatConsts#SIGNIF_BIT_MASK .
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Example 1
| Source File: Math.java From jdk1.8-source-analysis with Apache License 2.0 | 5 votes |
|
/**
* Returns the closest {@code int} to the argument, with ties
* rounding to positive infinity.
*
* <p>
* Special cases:
* <ul><li>If the argument is NaN, the result is 0.
* <li>If the argument is negative infinity or any value less than or
* equal to the value of {@code Integer.MIN_VALUE}, the result is
* equal to the value of {@code Integer.MIN_VALUE}.
* <li>If the argument is positive infinity or any value greater than or
* equal to the value of {@code Integer.MAX_VALUE}, the result is
* equal to the value of {@code Integer.MAX_VALUE}.</ul>
*
* @param a a floating-point value to be rounded to an integer.
* @return the value of the argument rounded to the nearest
* {@code int} value.
* @see java.lang.Integer#MAX_VALUE
* @see java.lang.Integer#MIN_VALUE
*/
public static int round(float a) {
int intBits = Float.floatToRawIntBits(a);
int biasedExp = (intBits & FloatConsts.EXP_BIT_MASK)
>> (FloatConsts.SIGNIFICAND_WIDTH - 1);
int shift = (FloatConsts.SIGNIFICAND_WIDTH - 2
+ FloatConsts.EXP_BIAS) - biasedExp;
if ((shift & -32) == 0) { // shift >= 0 && shift < 32
// a is a finite number such that pow(2,-32) <= ulp(a) < 1
int r = ((intBits & FloatConsts.SIGNIF_BIT_MASK)
| (FloatConsts.SIGNIF_BIT_MASK + 1));
if (intBits < 0) {
r = -r;
}
// In the comments below each Java expression evaluates to the value
// the corresponding mathematical expression:
// (r) evaluates to a / ulp(a)
// (r >> shift) evaluates to floor(a * 2)
// ((r >> shift) + 1) evaluates to floor((a + 1/2) * 2)
// (((r >> shift) + 1) >> 1) evaluates to floor(a + 1/2)
return ((r >> shift) + 1) >> 1;
} else {
// a is either
// - a finite number with abs(a) < exp(2,FloatConsts.SIGNIFICAND_WIDTH-32) < 1/2
// - a finite number with ulp(a) >= 1 and hence a is a mathematical integer
// - an infinity or NaN
return (int) a;
}
}
Example 2
| Source File: Math.java From JDKSourceCode1.8 with MIT License | 5 votes |
|
/**
* Returns the closest {@code int} to the argument, with ties
* rounding to positive infinity.
*
* <p>
* Special cases:
* <ul><li>If the argument is NaN, the result is 0.
* <li>If the argument is negative infinity or any value less than or
* equal to the value of {@code Integer.MIN_VALUE}, the result is
* equal to the value of {@code Integer.MIN_VALUE}.
* <li>If the argument is positive infinity or any value greater than or
* equal to the value of {@code Integer.MAX_VALUE}, the result is
* equal to the value of {@code Integer.MAX_VALUE}.</ul>
*
* @param a a floating-point value to be rounded to an integer.
* @return the value of the argument rounded to the nearest
* {@code int} value.
* @see java.lang.Integer#MAX_VALUE
* @see java.lang.Integer#MIN_VALUE
*/
public static int round(float a) {
int intBits = Float.floatToRawIntBits(a);
int biasedExp = (intBits & FloatConsts.EXP_BIT_MASK)
>> (FloatConsts.SIGNIFICAND_WIDTH - 1);
int shift = (FloatConsts.SIGNIFICAND_WIDTH - 2
+ FloatConsts.EXP_BIAS) - biasedExp;
if ((shift & -32) == 0) { // shift >= 0 && shift < 32
// a is a finite number such that pow(2,-32) <= ulp(a) < 1
int r = ((intBits & FloatConsts.SIGNIF_BIT_MASK)
| (FloatConsts.SIGNIF_BIT_MASK + 1));
if (intBits < 0) {
r = -r;
}
// In the comments below each Java expression evaluates to the value
// the corresponding mathematical expression:
// (r) evaluates to a / ulp(a)
// (r >> shift) evaluates to floor(a * 2)
// ((r >> shift) + 1) evaluates to floor((a + 1/2) * 2)
// (((r >> shift) + 1) >> 1) evaluates to floor(a + 1/2)
return ((r >> shift) + 1) >> 1;
} else {
// a is either
// - a finite number with abs(a) < exp(2,FloatConsts.SIGNIFICAND_WIDTH-32) < 1/2
// - a finite number with ulp(a) >= 1 and hence a is a mathematical integer
// - an infinity or NaN
return (int) a;
}
}
Example 3
| Source File: Math.java From openjdk-jdk8u-backup with GNU General Public License v2.0 | 5 votes |
|
/**
* Returns the closest {@code int} to the argument, with ties
* rounding to positive infinity.
*
* <p>
* Special cases:
* <ul><li>If the argument is NaN, the result is 0.
* <li>If the argument is negative infinity or any value less than or
* equal to the value of {@code Integer.MIN_VALUE}, the result is
* equal to the value of {@code Integer.MIN_VALUE}.
* <li>If the argument is positive infinity or any value greater than or
* equal to the value of {@code Integer.MAX_VALUE}, the result is
* equal to the value of {@code Integer.MAX_VALUE}.</ul>
*
* @param a a floating-point value to be rounded to an integer.
* @return the value of the argument rounded to the nearest
* {@code int} value.
* @see java.lang.Integer#MAX_VALUE
* @see java.lang.Integer#MIN_VALUE
*/
public static int round(float a) {
int intBits = Float.floatToRawIntBits(a);
int biasedExp = (intBits & FloatConsts.EXP_BIT_MASK)
>> (FloatConsts.SIGNIFICAND_WIDTH - 1);
int shift = (FloatConsts.SIGNIFICAND_WIDTH - 2
+ FloatConsts.EXP_BIAS) - biasedExp;
if ((shift & -32) == 0) { // shift >= 0 && shift < 32
// a is a finite number such that pow(2,-32) <= ulp(a) < 1
int r = ((intBits & FloatConsts.SIGNIF_BIT_MASK)
| (FloatConsts.SIGNIF_BIT_MASK + 1));
if (intBits < 0) {
r = -r;
}
// In the comments below each Java expression evaluates to the value
// the corresponding mathematical expression:
// (r) evaluates to a / ulp(a)
// (r >> shift) evaluates to floor(a * 2)
// ((r >> shift) + 1) evaluates to floor((a + 1/2) * 2)
// (((r >> shift) + 1) >> 1) evaluates to floor(a + 1/2)
return ((r >> shift) + 1) >> 1;
} else {
// a is either
// - a finite number with abs(a) < exp(2,FloatConsts.SIGNIFICAND_WIDTH-32) < 1/2
// - a finite number with ulp(a) >= 1 and hence a is a mathematical integer
// - an infinity or NaN
return (int) a;
}
}
Example 4
| Source File: Math.java From j2objc with Apache License 2.0 | 5 votes |
|
/**
* Returns the closest {@code int} to the argument, with ties
* rounding to positive infinity.
*
* <p>
* Special cases:
* <ul><li>If the argument is NaN, the result is 0.
* <li>If the argument is negative infinity or any value less than or
* equal to the value of {@code Integer.MIN_VALUE}, the result is
* equal to the value of {@code Integer.MIN_VALUE}.
* <li>If the argument is positive infinity or any value greater than or
* equal to the value of {@code Integer.MAX_VALUE}, the result is
* equal to the value of {@code Integer.MAX_VALUE}.</ul>
*
* @param a a floating-point value to be rounded to an integer.
* @return the value of the argument rounded to the nearest
* {@code int} value.
* @see java.lang.Integer#MAX_VALUE
* @see java.lang.Integer#MIN_VALUE
*/
public static int round(float a) {
int intBits = Float.floatToRawIntBits(a);
int biasedExp = (intBits & FloatConsts.EXP_BIT_MASK)
>> (FloatConsts.SIGNIFICAND_WIDTH - 1);
int shift = (FloatConsts.SIGNIFICAND_WIDTH - 2
+ FloatConsts.EXP_BIAS) - biasedExp;
if ((shift & -32) == 0) { // shift >= 0 && shift < 32
// a is a finite number such that pow(2,-32) <= ulp(a) < 1
int r = ((intBits & FloatConsts.SIGNIF_BIT_MASK)
| (FloatConsts.SIGNIF_BIT_MASK + 1));
if (intBits < 0) {
r = -r;
}
// In the comments below each Java expression evaluates to the value
// the corresponding mathematical expression:
// (r) evaluates to a / ulp(a)
// (r >> shift) evaluates to floor(a * 2)
// ((r >> shift) + 1) evaluates to floor((a + 1/2) * 2)
// (((r >> shift) + 1) >> 1) evaluates to floor(a + 1/2)
return ((r >> shift) + 1) >> 1;
} else {
// a is either
// - a finite number with abs(a) < exp(2,FloatConsts.SIGNIFICAND_WIDTH-32) < 1/2
// - a finite number with ulp(a) >= 1 and hence a is a mathematical integer
// - an infinity or NaN
return (int) a;
}
}
Example 5
| Source File: Math.java From jdk8u-jdk with GNU General Public License v2.0 | 5 votes |
|
/**
* Returns the closest {@code int} to the argument, with ties
* rounding to positive infinity.
*
* <p>
* Special cases:
* <ul><li>If the argument is NaN, the result is 0.
* <li>If the argument is negative infinity or any value less than or
* equal to the value of {@code Integer.MIN_VALUE}, the result is
* equal to the value of {@code Integer.MIN_VALUE}.
* <li>If the argument is positive infinity or any value greater than or
* equal to the value of {@code Integer.MAX_VALUE}, the result is
* equal to the value of {@code Integer.MAX_VALUE}.</ul>
*
* @param a a floating-point value to be rounded to an integer.
* @return the value of the argument rounded to the nearest
* {@code int} value.
* @see java.lang.Integer#MAX_VALUE
* @see java.lang.Integer#MIN_VALUE
*/
public static int round(float a) {
int intBits = Float.floatToRawIntBits(a);
int biasedExp = (intBits & FloatConsts.EXP_BIT_MASK)
>> (FloatConsts.SIGNIFICAND_WIDTH - 1);
int shift = (FloatConsts.SIGNIFICAND_WIDTH - 2
+ FloatConsts.EXP_BIAS) - biasedExp;
if ((shift & -32) == 0) { // shift >= 0 && shift < 32
// a is a finite number such that pow(2,-32) <= ulp(a) < 1
int r = ((intBits & FloatConsts.SIGNIF_BIT_MASK)
| (FloatConsts.SIGNIF_BIT_MASK + 1));
if (intBits < 0) {
r = -r;
}
// In the comments below each Java expression evaluates to the value
// the corresponding mathematical expression:
// (r) evaluates to a / ulp(a)
// (r >> shift) evaluates to floor(a * 2)
// ((r >> shift) + 1) evaluates to floor((a + 1/2) * 2)
// (((r >> shift) + 1) >> 1) evaluates to floor(a + 1/2)
return ((r >> shift) + 1) >> 1;
} else {
// a is either
// - a finite number with abs(a) < exp(2,FloatConsts.SIGNIFICAND_WIDTH-32) < 1/2
// - a finite number with ulp(a) >= 1 and hence a is a mathematical integer
// - an infinity or NaN
return (int) a;
}
}
Example 6
| Source File: Math.java From jdk8u-dev-jdk with GNU General Public License v2.0 | 5 votes |
|
/**
* Returns the closest {@code int} to the argument, with ties
* rounding to positive infinity.
*
* <p>
* Special cases:
* <ul><li>If the argument is NaN, the result is 0.
* <li>If the argument is negative infinity or any value less than or
* equal to the value of {@code Integer.MIN_VALUE}, the result is
* equal to the value of {@code Integer.MIN_VALUE}.
* <li>If the argument is positive infinity or any value greater than or
* equal to the value of {@code Integer.MAX_VALUE}, the result is
* equal to the value of {@code Integer.MAX_VALUE}.</ul>
*
* @param a a floating-point value to be rounded to an integer.
* @return the value of the argument rounded to the nearest
* {@code int} value.
* @see java.lang.Integer#MAX_VALUE
* @see java.lang.Integer#MIN_VALUE
*/
public static int round(float a) {
int intBits = Float.floatToRawIntBits(a);
int biasedExp = (intBits & FloatConsts.EXP_BIT_MASK)
>> (FloatConsts.SIGNIFICAND_WIDTH - 1);
int shift = (FloatConsts.SIGNIFICAND_WIDTH - 2
+ FloatConsts.EXP_BIAS) - biasedExp;
if ((shift & -32) == 0) { // shift >= 0 && shift < 32
// a is a finite number such that pow(2,-32) <= ulp(a) < 1
int r = ((intBits & FloatConsts.SIGNIF_BIT_MASK)
| (FloatConsts.SIGNIF_BIT_MASK + 1));
if (intBits < 0) {
r = -r;
}
// In the comments below each Java expression evaluates to the value
// the corresponding mathematical expression:
// (r) evaluates to a / ulp(a)
// (r >> shift) evaluates to floor(a * 2)
// ((r >> shift) + 1) evaluates to floor((a + 1/2) * 2)
// (((r >> shift) + 1) >> 1) evaluates to floor(a + 1/2)
return ((r >> shift) + 1) >> 1;
} else {
// a is either
// - a finite number with abs(a) < exp(2,FloatConsts.SIGNIFICAND_WIDTH-32) < 1/2
// - a finite number with ulp(a) >= 1 and hence a is a mathematical integer
// - an infinity or NaN
return (int) a;
}
}
Example 7
| Source File: Math.java From dragonwell8_jdk with GNU General Public License v2.0 | 5 votes |
|
/**
* Returns the closest {@code int} to the argument, with ties
* rounding to positive infinity.
*
* <p>
* Special cases:
* <ul><li>If the argument is NaN, the result is 0.
* <li>If the argument is negative infinity or any value less than or
* equal to the value of {@code Integer.MIN_VALUE}, the result is
* equal to the value of {@code Integer.MIN_VALUE}.
* <li>If the argument is positive infinity or any value greater than or
* equal to the value of {@code Integer.MAX_VALUE}, the result is
* equal to the value of {@code Integer.MAX_VALUE}.</ul>
*
* @param a a floating-point value to be rounded to an integer.
* @return the value of the argument rounded to the nearest
* {@code int} value.
* @see java.lang.Integer#MAX_VALUE
* @see java.lang.Integer#MIN_VALUE
*/
public static int round(float a) {
int intBits = Float.floatToRawIntBits(a);
int biasedExp = (intBits & FloatConsts.EXP_BIT_MASK)
>> (FloatConsts.SIGNIFICAND_WIDTH - 1);
int shift = (FloatConsts.SIGNIFICAND_WIDTH - 2
+ FloatConsts.EXP_BIAS) - biasedExp;
if ((shift & -32) == 0) { // shift >= 0 && shift < 32
// a is a finite number such that pow(2,-32) <= ulp(a) < 1
int r = ((intBits & FloatConsts.SIGNIF_BIT_MASK)
| (FloatConsts.SIGNIF_BIT_MASK + 1));
if (intBits < 0) {
r = -r;
}
// In the comments below each Java expression evaluates to the value
// the corresponding mathematical expression:
// (r) evaluates to a / ulp(a)
// (r >> shift) evaluates to floor(a * 2)
// ((r >> shift) + 1) evaluates to floor((a + 1/2) * 2)
// (((r >> shift) + 1) >> 1) evaluates to floor(a + 1/2)
return ((r >> shift) + 1) >> 1;
} else {
// a is either
// - a finite number with abs(a) < exp(2,FloatConsts.SIGNIFICAND_WIDTH-32) < 1/2
// - a finite number with ulp(a) >= 1 and hence a is a mathematical integer
// - an infinity or NaN
return (int) a;
}
}
Example 8
| Source File: FpUtils.java From openjdk-8 with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 9
| Source File: BigInteger.java From openjdk-jdk8u with GNU General Public License v2.0 | 4 votes |
|
/**
* Converts this BigInteger to a {@code float}. This
* conversion is similar to the
* <i>narrowing primitive conversion</i> from {@code double} to
* {@code float} as defined in section 5.1.3 of
* <cite>The Java™ Language Specification</cite>:
* if this BigInteger has too great a magnitude
* to represent as a {@code float}, it will be converted to
* {@link Float#NEGATIVE_INFINITY} or {@link
* Float#POSITIVE_INFINITY} as appropriate. Note that even when
* the return value is finite, this conversion can lose
* information about the precision of the BigInteger value.
*
* @return this BigInteger converted to a {@code float}.
*/
public float floatValue() {
if (signum == 0) {
return 0.0f;
}
int exponent = ((mag.length - 1) << 5) + bitLengthForInt(mag[0]) - 1;
// exponent == floor(log2(abs(this)))
if (exponent < Long.SIZE - 1) {
return longValue();
} else if (exponent > Float.MAX_EXPONENT) {
return signum > 0 ? Float.POSITIVE_INFINITY : Float.NEGATIVE_INFINITY;
}
/*
* We need the top SIGNIFICAND_WIDTH bits, including the "implicit"
* one bit. To make rounding easier, we pick out the top
* SIGNIFICAND_WIDTH + 1 bits, so we have one to help us round up or
* down. twiceSignifFloor will contain the top SIGNIFICAND_WIDTH + 1
* bits, and signifFloor the top SIGNIFICAND_WIDTH.
*
* It helps to consider the real number signif = abs(this) *
* 2^(SIGNIFICAND_WIDTH - 1 - exponent).
*/
int shift = exponent - FloatConsts.SIGNIFICAND_WIDTH;
int twiceSignifFloor;
// twiceSignifFloor will be == abs().shiftRight(shift).intValue()
// We do the shift into an int directly to improve performance.
int nBits = shift & 0x1f;
int nBits2 = 32 - nBits;
if (nBits == 0) {
twiceSignifFloor = mag[0];
} else {
twiceSignifFloor = mag[0] >>> nBits;
if (twiceSignifFloor == 0) {
twiceSignifFloor = (mag[0] << nBits2) | (mag[1] >>> nBits);
}
}
int signifFloor = twiceSignifFloor >> 1;
signifFloor &= FloatConsts.SIGNIF_BIT_MASK; // remove the implied bit
/*
* We round up if either the fractional part of signif is strictly
* greater than 0.5 (which is true if the 0.5 bit is set and any lower
* bit is set), or if the fractional part of signif is >= 0.5 and
* signifFloor is odd (which is true if both the 0.5 bit and the 1 bit
* are set). This is equivalent to the desired HALF_EVEN rounding.
*/
boolean increment = (twiceSignifFloor & 1) != 0
&& ((signifFloor & 1) != 0 || abs().getLowestSetBit() < shift);
int signifRounded = increment ? signifFloor + 1 : signifFloor;
int bits = ((exponent + FloatConsts.EXP_BIAS))
<< (FloatConsts.SIGNIFICAND_WIDTH - 1);
bits += signifRounded;
/*
* If signifRounded == 2^24, we'd need to set all of the significand
* bits to zero and add 1 to the exponent. This is exactly the behavior
* we get from just adding signifRounded to bits directly. If the
* exponent is Float.MAX_EXPONENT, we round up (correctly) to
* Float.POSITIVE_INFINITY.
*/
bits |= signum & FloatConsts.SIGN_BIT_MASK;
return Float.intBitsToFloat(bits);
}
Example 10
| Source File: BigInteger.java From Java8CN with Apache License 2.0 | 4 votes |
|
/**
* Converts this BigInteger to a {@code float}. This
* conversion is similar to the
* <i>narrowing primitive conversion</i> from {@code double} to
* {@code float} as defined in section 5.1.3 of
* <cite>The Java™ Language Specification</cite>:
* if this BigInteger has too great a magnitude
* to represent as a {@code float}, it will be converted to
* {@link Float#NEGATIVE_INFINITY} or {@link
* Float#POSITIVE_INFINITY} as appropriate. Note that even when
* the return value is finite, this conversion can lose
* information about the precision of the BigInteger value.
*
* @return this BigInteger converted to a {@code float}.
*/
public float floatValue() {
if (signum == 0) {
return 0.0f;
}
int exponent = ((mag.length - 1) << 5) + bitLengthForInt(mag[0]) - 1;
// exponent == floor(log2(abs(this)))
if (exponent < Long.SIZE - 1) {
return longValue();
} else if (exponent > Float.MAX_EXPONENT) {
return signum > 0 ? Float.POSITIVE_INFINITY : Float.NEGATIVE_INFINITY;
}
/*
* We need the top SIGNIFICAND_WIDTH bits, including the "implicit"
* one bit. To make rounding easier, we pick out the top
* SIGNIFICAND_WIDTH + 1 bits, so we have one to help us round up or
* down. twiceSignifFloor will contain the top SIGNIFICAND_WIDTH + 1
* bits, and signifFloor the top SIGNIFICAND_WIDTH.
*
* It helps to consider the real number signif = abs(this) *
* 2^(SIGNIFICAND_WIDTH - 1 - exponent).
*/
int shift = exponent - FloatConsts.SIGNIFICAND_WIDTH;
int twiceSignifFloor;
// twiceSignifFloor will be == abs().shiftRight(shift).intValue()
// We do the shift into an int directly to improve performance.
int nBits = shift & 0x1f;
int nBits2 = 32 - nBits;
if (nBits == 0) {
twiceSignifFloor = mag[0];
} else {
twiceSignifFloor = mag[0] >>> nBits;
if (twiceSignifFloor == 0) {
twiceSignifFloor = (mag[0] << nBits2) | (mag[1] >>> nBits);
}
}
int signifFloor = twiceSignifFloor >> 1;
signifFloor &= FloatConsts.SIGNIF_BIT_MASK; // remove the implied bit
/*
* We round up if either the fractional part of signif is strictly
* greater than 0.5 (which is true if the 0.5 bit is set and any lower
* bit is set), or if the fractional part of signif is >= 0.5 and
* signifFloor is odd (which is true if both the 0.5 bit and the 1 bit
* are set). This is equivalent to the desired HALF_EVEN rounding.
*/
boolean increment = (twiceSignifFloor & 1) != 0
&& ((signifFloor & 1) != 0 || abs().getLowestSetBit() < shift);
int signifRounded = increment ? signifFloor + 1 : signifFloor;
int bits = ((exponent + FloatConsts.EXP_BIAS))
<< (FloatConsts.SIGNIFICAND_WIDTH - 1);
bits += signifRounded;
/*
* If signifRounded == 2^24, we'd need to set all of the significand
* bits to zero and add 1 to the exponent. This is exactly the behavior
* we get from just adding signifRounded to bits directly. If the
* exponent is Float.MAX_EXPONENT, we round up (correctly) to
* Float.POSITIVE_INFINITY.
*/
bits |= signum & FloatConsts.SIGN_BIT_MASK;
return Float.intBitsToFloat(bits);
}
Example 11
| Source File: FpUtils.java From jdk8u_jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 12
| Source File: FpUtils.java From jdk8u-jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 13
| Source File: BigInteger.java From jdk8u-jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Converts this BigInteger to a {@code float}. This
* conversion is similar to the
* <i>narrowing primitive conversion</i> from {@code double} to
* {@code float} as defined in section 5.1.3 of
* <cite>The Java™ Language Specification</cite>:
* if this BigInteger has too great a magnitude
* to represent as a {@code float}, it will be converted to
* {@link Float#NEGATIVE_INFINITY} or {@link
* Float#POSITIVE_INFINITY} as appropriate. Note that even when
* the return value is finite, this conversion can lose
* information about the precision of the BigInteger value.
*
* @return this BigInteger converted to a {@code float}.
*/
public float floatValue() {
if (signum == 0) {
return 0.0f;
}
int exponent = ((mag.length - 1) << 5) + bitLengthForInt(mag[0]) - 1;
// exponent == floor(log2(abs(this)))
if (exponent < Long.SIZE - 1) {
return longValue();
} else if (exponent > Float.MAX_EXPONENT) {
return signum > 0 ? Float.POSITIVE_INFINITY : Float.NEGATIVE_INFINITY;
}
/*
* We need the top SIGNIFICAND_WIDTH bits, including the "implicit"
* one bit. To make rounding easier, we pick out the top
* SIGNIFICAND_WIDTH + 1 bits, so we have one to help us round up or
* down. twiceSignifFloor will contain the top SIGNIFICAND_WIDTH + 1
* bits, and signifFloor the top SIGNIFICAND_WIDTH.
*
* It helps to consider the real number signif = abs(this) *
* 2^(SIGNIFICAND_WIDTH - 1 - exponent).
*/
int shift = exponent - FloatConsts.SIGNIFICAND_WIDTH;
int twiceSignifFloor;
// twiceSignifFloor will be == abs().shiftRight(shift).intValue()
// We do the shift into an int directly to improve performance.
int nBits = shift & 0x1f;
int nBits2 = 32 - nBits;
if (nBits == 0) {
twiceSignifFloor = mag[0];
} else {
twiceSignifFloor = mag[0] >>> nBits;
if (twiceSignifFloor == 0) {
twiceSignifFloor = (mag[0] << nBits2) | (mag[1] >>> nBits);
}
}
int signifFloor = twiceSignifFloor >> 1;
signifFloor &= FloatConsts.SIGNIF_BIT_MASK; // remove the implied bit
/*
* We round up if either the fractional part of signif is strictly
* greater than 0.5 (which is true if the 0.5 bit is set and any lower
* bit is set), or if the fractional part of signif is >= 0.5 and
* signifFloor is odd (which is true if both the 0.5 bit and the 1 bit
* are set). This is equivalent to the desired HALF_EVEN rounding.
*/
boolean increment = (twiceSignifFloor & 1) != 0
&& ((signifFloor & 1) != 0 || abs().getLowestSetBit() < shift);
int signifRounded = increment ? signifFloor + 1 : signifFloor;
int bits = ((exponent + FloatConsts.EXP_BIAS))
<< (FloatConsts.SIGNIFICAND_WIDTH - 1);
bits += signifRounded;
/*
* If signifRounded == 2^24, we'd need to set all of the significand
* bits to zero and add 1 to the exponent. This is exactly the behavior
* we get from just adding signifRounded to bits directly. If the
* exponent is Float.MAX_EXPONENT, we round up (correctly) to
* Float.POSITIVE_INFINITY.
*/
bits |= signum & FloatConsts.SIGN_BIT_MASK;
return Float.intBitsToFloat(bits);
}
Example 14
| Source File: FpUtils.java From hottub with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 15
| Source File: FpUtils.java From jdk8u-dev-jdk with GNU General Public License v2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 16
| Source File: FpUtils.java From j2objc with Apache License 2.0 | 4 votes |
|
/**
* Returns unbiased exponent of a {@code float}; for
* subnormal values, the number is treated as if it were
* normalized. That is for all finite, non-zero, positive numbers
* <i>x</i>, <code>scalb(<i>x</i>, -ilogb(<i>x</i>))</code> is
* always in the range [1, 2).
* <p>
* Special cases:
* <ul>
* <li> If the argument is NaN, then the result is 2<sup>30</sup>.
* <li> If the argument is infinite, then the result is 2<sup>28</sup>.
* <li> If the argument is zero, then the result is -(2<sup>28</sup>).
* </ul>
*
* @param f floating-point number whose exponent is to be extracted
* @return unbiased exponent of the argument.
* @author Joseph D. Darcy
*/
public static int ilogb(float f) {
int exponent = getExponent(f);
switch (exponent) {
case FloatConsts.MAX_EXPONENT+1: // NaN or infinity
if( isNaN(f) )
return (1<<30); // 2^30
else // infinite value
return (1<<28); // 2^28
case FloatConsts.MIN_EXPONENT-1: // zero or subnormal
if(f == 0.0f) {
return -(1<<28); // -(2^28)
}
else {
int transducer = Float.floatToRawIntBits(f);
/*
* To avoid causing slow arithmetic on subnormals,
* the scaling to determine when f's significand
* is normalized is done in integer arithmetic.
* (there must be at least one "1" bit in the
* significand since zero has been screened out.
*/
// isolate significand bits
transducer &= FloatConsts.SIGNIF_BIT_MASK;
assert(transducer != 0);
// This loop is simple and functional. We might be
// able to do something more clever that was faster;
// e.g. number of leading zero detection on
// (transducer << (# exponent and sign bits).
while (transducer <
(1 << (FloatConsts.SIGNIFICAND_WIDTH - 1))) {
transducer *= 2;
exponent--;
}
exponent++;
assert( exponent >=
FloatConsts.MIN_EXPONENT - (FloatConsts.SIGNIFICAND_WIDTH-1) &&
exponent < FloatConsts.MIN_EXPONENT);
return exponent;
}
default:
assert( exponent >= FloatConsts.MIN_EXPONENT &&
exponent <= FloatConsts.MAX_EXPONENT);
return exponent;
}
}
Example 17
| Source File: Float.java From AndroidComponentPlugin with Apache License 2.0 | 3 votes |
|
/**
* Returns a representation of the specified floating-point value
* according to the IEEE 754 floating-point "single format" bit
* layout.
*
* <p>Bit 31 (the bit that is selected by the mask
* {@code 0x80000000}) represents the sign of the floating-point
* number.
* Bits 30-23 (the bits that are selected by the mask
* {@code 0x7f800000}) represent the exponent.
* Bits 22-0 (the bits that are selected by the mask
* {@code 0x007fffff}) represent the significand (sometimes called
* the mantissa) of the floating-point number.
*
* <p>If the argument is positive infinity, the result is
* {@code 0x7f800000}.
*
* <p>If the argument is negative infinity, the result is
* {@code 0xff800000}.
*
* <p>If the argument is NaN, the result is {@code 0x7fc00000}.
*
* <p>In all cases, the result is an integer that, when given to the
* {@link #intBitsToFloat(int)} method, will produce a floating-point
* value the same as the argument to {@code floatToIntBits}
* (except all NaN values are collapsed to a single
* "canonical" NaN value).
*
* @param value a floating-point number.
* @return the bits that represent the floating-point number.
*/
public static int floatToIntBits(float value) {
int result = floatToRawIntBits(value);
// Check for NaN based on values of bit fields, maximum
// exponent and nonzero significand.
if ( ((result & FloatConsts.EXP_BIT_MASK) ==
FloatConsts.EXP_BIT_MASK) &&
(result & FloatConsts.SIGNIF_BIT_MASK) != 0)
result = 0x7fc00000;
return result;
}
Example 18
| Source File: Float.java From jdk8u-dev-jdk with GNU General Public License v2.0 | 3 votes |
|
/**
* Returns a representation of the specified floating-point value
* according to the IEEE 754 floating-point "single format" bit
* layout.
*
* <p>Bit 31 (the bit that is selected by the mask
* {@code 0x80000000}) represents the sign of the floating-point
* number.
* Bits 30-23 (the bits that are selected by the mask
* {@code 0x7f800000}) represent the exponent.
* Bits 22-0 (the bits that are selected by the mask
* {@code 0x007fffff}) represent the significand (sometimes called
* the mantissa) of the floating-point number.
*
* <p>If the argument is positive infinity, the result is
* {@code 0x7f800000}.
*
* <p>If the argument is negative infinity, the result is
* {@code 0xff800000}.
*
* <p>If the argument is NaN, the result is {@code 0x7fc00000}.
*
* <p>In all cases, the result is an integer that, when given to the
* {@link #intBitsToFloat(int)} method, will produce a floating-point
* value the same as the argument to {@code floatToIntBits}
* (except all NaN values are collapsed to a single
* "canonical" NaN value).
*
* @param value a floating-point number.
* @return the bits that represent the floating-point number.
*/
public static int floatToIntBits(float value) {
int result = floatToRawIntBits(value);
// Check for NaN based on values of bit fields, maximum
// exponent and nonzero significand.
if ( ((result & FloatConsts.EXP_BIT_MASK) ==
FloatConsts.EXP_BIT_MASK) &&
(result & FloatConsts.SIGNIF_BIT_MASK) != 0)
result = 0x7fc00000;
return result;
}
Example 19
| Source File: Float.java From jdk8u60 with GNU General Public License v2.0 | 3 votes |
|
/**
* Returns a representation of the specified floating-point value
* according to the IEEE 754 floating-point "single format" bit
* layout.
*
* <p>Bit 31 (the bit that is selected by the mask
* {@code 0x80000000}) represents the sign of the floating-point
* number.
* Bits 30-23 (the bits that are selected by the mask
* {@code 0x7f800000}) represent the exponent.
* Bits 22-0 (the bits that are selected by the mask
* {@code 0x007fffff}) represent the significand (sometimes called
* the mantissa) of the floating-point number.
*
* <p>If the argument is positive infinity, the result is
* {@code 0x7f800000}.
*
* <p>If the argument is negative infinity, the result is
* {@code 0xff800000}.
*
* <p>If the argument is NaN, the result is {@code 0x7fc00000}.
*
* <p>In all cases, the result is an integer that, when given to the
* {@link #intBitsToFloat(int)} method, will produce a floating-point
* value the same as the argument to {@code floatToIntBits}
* (except all NaN values are collapsed to a single
* "canonical" NaN value).
*
* @param value a floating-point number.
* @return the bits that represent the floating-point number.
*/
public static int floatToIntBits(float value) {
int result = floatToRawIntBits(value);
// Check for NaN based on values of bit fields, maximum
// exponent and nonzero significand.
if ( ((result & FloatConsts.EXP_BIT_MASK) ==
FloatConsts.EXP_BIT_MASK) &&
(result & FloatConsts.SIGNIF_BIT_MASK) != 0)
result = 0x7fc00000;
return result;
}
Example 20
| Source File: Float.java From j2objc with Apache License 2.0 | 3 votes |
|
/**
* Returns a representation of the specified floating-point value
* according to the IEEE 754 floating-point "single format" bit
* layout.
*
* <p>Bit 31 (the bit that is selected by the mask
* {@code 0x80000000}) represents the sign of the floating-point
* number.
* Bits 30-23 (the bits that are selected by the mask
* {@code 0x7f800000}) represent the exponent.
* Bits 22-0 (the bits that are selected by the mask
* {@code 0x007fffff}) represent the significand (sometimes called
* the mantissa) of the floating-point number.
*
* <p>If the argument is positive infinity, the result is
* {@code 0x7f800000}.
*
* <p>If the argument is negative infinity, the result is
* {@code 0xff800000}.
*
* <p>If the argument is NaN, the result is {@code 0x7fc00000}.
*
* <p>In all cases, the result is an integer that, when given to the
* {@link #intBitsToFloat(int)} method, will produce a floating-point
* value the same as the argument to {@code floatToIntBits}
* (except all NaN values are collapsed to a single
* "canonical" NaN value).
*
* @param value a floating-point number.
* @return the bits that represent the floating-point number.
*/
public static int floatToIntBits(float value) {
int result = floatToRawIntBits(value);
// Check for NaN based on values of bit fields, maximum
// exponent and nonzero significand.
if ( ((result & FloatConsts.EXP_BIT_MASK) ==
FloatConsts.EXP_BIT_MASK) &&
(result & FloatConsts.SIGNIF_BIT_MASK) != 0)
result = 0x7fc00000;
return result;
}
