|
|
/* @(#)s_lrint.c 5.1 93/09/24 */
|
/* @(#)s_lrint.c 5.1 93/09/24 */
|
/*
|
/*
|
* ====================================================
|
* ====================================================
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
*
|
*
|
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
* Permission to use, copy, modify, and distribute this
|
* Permission to use, copy, modify, and distribute this
|
* software is freely granted, provided that this notice
|
* software is freely granted, provided that this notice
|
* is preserved.
|
* is preserved.
|
* ====================================================
|
* ====================================================
|
*/
|
*/
|
|
|
/*
|
/*
|
* lrint(x)
|
* lrint(x)
|
* Return x rounded to integral value according to the prevailing
|
* Return x rounded to integral value according to the prevailing
|
* rounding mode.
|
* rounding mode.
|
* Method:
|
* Method:
|
* Using floating addition.
|
* Using floating addition.
|
* Exception:
|
* Exception:
|
* Inexact flag raised if x not equal to lrint(x).
|
* Inexact flag raised if x not equal to lrint(x).
|
*/
|
*/
|
|
|
#include "fdlibm.h"
|
#include "fdlibm.h"
|
|
|
#ifndef _DOUBLE_IS_32BITS
|
#ifndef _DOUBLE_IS_32BITS
|
|
|
#ifdef __STDC__
|
#ifdef __STDC__
|
static const double
|
static const double
|
#else
|
#else
|
static double
|
static double
|
#endif
|
#endif
|
|
|
/* Adding a double, x, to 2^52 will cause the result to be rounded based on
|
/* Adding a double, x, to 2^52 will cause the result to be rounded based on
|
the fractional part of x, according to the implementation's current rounding
|
the fractional part of x, according to the implementation's current rounding
|
mode. 2^52 is the smallest double that can be represented using all 52 significant
|
mode. 2^52 is the smallest double that can be represented using all 52 significant
|
digits. */
|
digits. */
|
TWO52[2]={
|
TWO52[2]={
|
4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
|
4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
|
-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
|
-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
|
};
|
};
|
|
|
#ifdef __STDC__
|
#ifdef __STDC__
|
long int lrint(double x)
|
long int lrint(double x)
|
#else
|
#else
|
long int lrint(x)
|
long int lrint(x)
|
double x;
|
double x;
|
#endif
|
#endif
|
{
|
{
|
__int32_t i0,j0,sx;
|
__int32_t i0,j0,sx;
|
__uint32_t i1;
|
__uint32_t i1;
|
double t;
|
double t;
|
volatile double w;
|
volatile double w;
|
long int result;
|
long int result;
|
|
|
EXTRACT_WORDS(i0,i1,x);
|
EXTRACT_WORDS(i0,i1,x);
|
|
|
/* Extract sign bit. */
|
/* Extract sign bit. */
|
sx = (i0>>31)&1;
|
sx = (i0>>31)&1;
|
|
|
/* Extract exponent field. */
|
/* Extract exponent field. */
|
j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
|
j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
|
|
|
if(j0 < 20)
|
if(j0 < 20)
|
{
|
{
|
if(j0 < -1)
|
if(j0 < -1)
|
return 0;
|
return 0;
|
else
|
else
|
{
|
{
|
w = TWO52[sx] + x;
|
w = TWO52[sx] + x;
|
t = w - TWO52[sx];
|
t = w - TWO52[sx];
|
GET_HIGH_WORD(i0, t);
|
GET_HIGH_WORD(i0, t);
|
/* Detect the all-zeros representation of plus and
|
/* Detect the all-zeros representation of plus and
|
minus zero, which fails the calculation below. */
|
minus zero, which fails the calculation below. */
|
if ((i0 & ~(1 << 31)) == 0)
|
if ((i0 & ~(1 << 31)) == 0)
|
return 0;
|
return 0;
|
j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
|
j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
|
i0 &= 0x000fffff;
|
i0 &= 0x000fffff;
|
i0 |= 0x00100000;
|
i0 |= 0x00100000;
|
result = i0 >> (20 - j0);
|
result = i0 >> (20 - j0);
|
}
|
}
|
}
|
}
|
else if (j0 < (int)(8 * sizeof (long int)) - 1)
|
else if (j0 < (int)(8 * sizeof (long int)) - 1)
|
{
|
{
|
if (j0 >= 52)
|
if (j0 >= 52)
|
result = ((long int) ((i0 & 0x000fffff) | 0x0010000) << (j0 - 20)) |
|
result = ((long int) ((i0 & 0x000fffff) | 0x0010000) << (j0 - 20)) |
|
(i1 << (j0 - 52));
|
(i1 << (j0 - 52));
|
else
|
else
|
{
|
{
|
w = TWO52[sx] + x;
|
w = TWO52[sx] + x;
|
t = w - TWO52[sx];
|
t = w - TWO52[sx];
|
EXTRACT_WORDS (i0, i1, t);
|
EXTRACT_WORDS (i0, i1, t);
|
j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
|
j0 = ((i0 & 0x7ff00000) >> 20) - 1023;
|
i0 &= 0x000fffff;
|
i0 &= 0x000fffff;
|
i0 |= 0x00100000;
|
i0 |= 0x00100000;
|
result = ((long int) i0 << (j0 - 20)) | (i1 >> (52 - j0));
|
result = ((long int) i0 << (j0 - 20)) | (i1 >> (52 - j0));
|
}
|
}
|
}
|
}
|
else
|
else
|
{
|
{
|
return (long int) x;
|
return (long int) x;
|
}
|
}
|
|
|
return sx ? -result : result;
|
return sx ? -result : result;
|
}
|
}
|
|
|
#endif /* _DOUBLE_IS_32BITS */
|
#endif /* _DOUBLE_IS_32BITS */
|
|
|
