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Original imported versions of s_rint.c and math_private.h.

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Ben Gras 2007-12-11 12:32:26 +00:00
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commit bd489b6c0b
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272
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/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
* from: @(#)fdlibm.h 5.1 93/09/24
* $FreeBSD: src/lib/msun/src/math_private.h,v 1.17.2.2 2007/06/13 18:17:25 bde Exp $
*/
#ifndef _MATH_PRIVATE_H_
#define _MATH_PRIVATE_H_
#include <sys/types.h>
#include <machine/endian.h>
/*
* The original fdlibm code used statements like:
* n0 = ((*(int*)&one)>>29)^1; * index of high word *
* ix0 = *(n0+(int*)&x); * high word of x *
* ix1 = *((1-n0)+(int*)&x); * low word of x *
* to dig two 32 bit words out of the 64 bit IEEE floating point
* value. That is non-ANSI, and, moreover, the gcc instruction
* scheduler gets it wrong. We instead use the following macros.
* Unlike the original code, we determine the endianness at compile
* time, not at run time; I don't see much benefit to selecting
* endianness at run time.
*/
/*
* A union which permits us to convert between a double and two 32 bit
* ints.
*/
#if BYTE_ORDER == BIG_ENDIAN
typedef union
{
double value;
struct
{
u_int32_t msw;
u_int32_t lsw;
} parts;
} ieee_double_shape_type;
#endif
#if BYTE_ORDER == LITTLE_ENDIAN
typedef union
{
double value;
struct
{
u_int32_t lsw;
u_int32_t msw;
} parts;
} ieee_double_shape_type;
#endif
/* Get two 32 bit ints from a double. */
#define EXTRACT_WORDS(ix0,ix1,d) \
do { \
ieee_double_shape_type ew_u; \
ew_u.value = (d); \
(ix0) = ew_u.parts.msw; \
(ix1) = ew_u.parts.lsw; \
} while (0)
/* Get the more significant 32 bit int from a double. */
#define GET_HIGH_WORD(i,d) \
do { \
ieee_double_shape_type gh_u; \
gh_u.value = (d); \
(i) = gh_u.parts.msw; \
} while (0)
/* Get the less significant 32 bit int from a double. */
#define GET_LOW_WORD(i,d) \
do { \
ieee_double_shape_type gl_u; \
gl_u.value = (d); \
(i) = gl_u.parts.lsw; \
} while (0)
/* Set a double from two 32 bit ints. */
#define INSERT_WORDS(d,ix0,ix1) \
do { \
ieee_double_shape_type iw_u; \
iw_u.parts.msw = (ix0); \
iw_u.parts.lsw = (ix1); \
(d) = iw_u.value; \
} while (0)
/* Set the more significant 32 bits of a double from an int. */
#define SET_HIGH_WORD(d,v) \
do { \
ieee_double_shape_type sh_u; \
sh_u.value = (d); \
sh_u.parts.msw = (v); \
(d) = sh_u.value; \
} while (0)
/* Set the less significant 32 bits of a double from an int. */
#define SET_LOW_WORD(d,v) \
do { \
ieee_double_shape_type sl_u; \
sl_u.value = (d); \
sl_u.parts.lsw = (v); \
(d) = sl_u.value; \
} while (0)
/*
* A union which permits us to convert between a float and a 32 bit
* int.
*/
typedef union
{
float value;
/* FIXME: Assumes 32 bit int. */
unsigned int word;
} ieee_float_shape_type;
/* Get a 32 bit int from a float. */
#define GET_FLOAT_WORD(i,d) \
do { \
ieee_float_shape_type gf_u; \
gf_u.value = (d); \
(i) = gf_u.word; \
} while (0)
/* Set a float from a 32 bit int. */
#define SET_FLOAT_WORD(d,i) \
do { \
ieee_float_shape_type sf_u; \
sf_u.word = (i); \
(d) = sf_u.value; \
} while (0)
#ifdef _COMPLEX_H
/*
* Inline functions that can be used to construct complex values.
*
* The C99 standard intends x+I*y to be used for this, but x+I*y is
* currently unusable in general since gcc introduces many overflow,
* underflow, sign and efficiency bugs by rewriting I*y as
* (0.0+I)*(y+0.0*I) and laboriously computing the full complex product.
* In particular, I*Inf is corrupted to NaN+I*Inf, and I*-0 is corrupted
* to -0.0+I*0.0.
*/
static __inline float complex
cpackf(float x, float y)
{
float complex z;
__real__ z = x;
__imag__ z = y;
return (z);
}
static __inline double complex
cpack(double x, double y)
{
double complex z;
__real__ z = x;
__imag__ z = y;
return (z);
}
static __inline long double complex
cpackl(long double x, long double y)
{
long double complex z;
__real__ z = x;
__imag__ z = y;
return (z);
}
#endif /* _COMPLEX_H */
/*
* ieee style elementary functions
*
* We rename functions here to improve other sources' diffability
* against fdlibm.
*/
#define __ieee754_sqrt sqrt
#define __ieee754_acos acos
#define __ieee754_acosh acosh
#define __ieee754_log log
#define __ieee754_atanh atanh
#define __ieee754_asin asin
#define __ieee754_atan2 atan2
#define __ieee754_exp exp
#define __ieee754_cosh cosh
#define __ieee754_fmod fmod
#define __ieee754_pow pow
#define __ieee754_lgamma lgamma
#define __ieee754_gamma gamma
#define __ieee754_lgamma_r lgamma_r
#define __ieee754_gamma_r gamma_r
#define __ieee754_log10 log10
#define __ieee754_sinh sinh
#define __ieee754_hypot hypot
#define __ieee754_j0 j0
#define __ieee754_j1 j1
#define __ieee754_y0 y0
#define __ieee754_y1 y1
#define __ieee754_jn jn
#define __ieee754_yn yn
#define __ieee754_remainder remainder
#define __ieee754_scalb scalb
#define __ieee754_sqrtf sqrtf
#define __ieee754_acosf acosf
#define __ieee754_acoshf acoshf
#define __ieee754_logf logf
#define __ieee754_atanhf atanhf
#define __ieee754_asinf asinf
#define __ieee754_atan2f atan2f
#define __ieee754_expf expf
#define __ieee754_coshf coshf
#define __ieee754_fmodf fmodf
#define __ieee754_powf powf
#define __ieee754_lgammaf lgammaf
#define __ieee754_gammaf gammaf
#define __ieee754_lgammaf_r lgammaf_r
#define __ieee754_gammaf_r gammaf_r
#define __ieee754_log10f log10f
#define __ieee754_sinhf sinhf
#define __ieee754_hypotf hypotf
#define __ieee754_j0f j0f
#define __ieee754_j1f j1f
#define __ieee754_y0f y0f
#define __ieee754_y1f y1f
#define __ieee754_jnf jnf
#define __ieee754_ynf ynf
#define __ieee754_remainderf remainderf
#define __ieee754_scalbf scalbf
/* fdlibm kernel function */
int __ieee754_rem_pio2(double,double*);
double __kernel_sin(double,double,int);
double __kernel_cos(double,double);
double __kernel_tan(double,double,int);
int __kernel_rem_pio2(double*,double*,int,int,int,const int*);
/* float versions of fdlibm kernel functions */
int __ieee754_rem_pio2f(float,float*);
float __kernel_sindf(double);
float __kernel_cosdf(double);
float __kernel_tandf(double,int);
int __kernel_rem_pio2f(float*,float*,int,int,int,const int*);
#endif /* !_MATH_PRIVATE_H_ */

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/* @(#)s_rint.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#ifndef lint
static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_rint.c,v 1.11.2.1 2007/06/14 05:16:44 bde Exp $";
#endif
/*
* rint(x)
* Return x rounded to integral value according to the prevailing
* rounding mode.
* Method:
* Using floating addition.
* Exception:
* Inexact flag raised if x not equal to rint(x).
*/
#include "math.h"
#include "math_private.h"
static const double
TWO52[2]={
4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
};
double
rint(double x)
{
int32_t i0,j0,sx;
u_int32_t i,i1;
double w,t;
EXTRACT_WORDS(i0,i1,x);
sx = (i0>>31)&1;
j0 = ((i0>>20)&0x7ff)-0x3ff;
if(j0<20) {
if(j0<0) {
if(((i0&0x7fffffff)|i1)==0) return x;
i1 |= (i0&0x0fffff);
i0 &= 0xfffe0000;
i0 |= ((i1|-i1)>>12)&0x80000;
SET_HIGH_WORD(x,i0);
w = TWO52[sx]+x;
t = w-TWO52[sx];
GET_HIGH_WORD(i0,t);
SET_HIGH_WORD(t,(i0&0x7fffffff)|(sx<<31));
return t;
} else {
i = (0x000fffff)>>j0;
if(((i0&i)|i1)==0) return x; /* x is integral */
i>>=1;
if(((i0&i)|i1)!=0) {
/*
* Some bit is set after the 0.5 bit. To avoid the
* possibility of errors from double rounding in
* w = TWO52[sx]+x, adjust the 0.25 bit to a lower
* guard bit. We do this for all j0<=51. The
* adjustment is trickiest for j0==18 and j0==19
* since then it spans the word boundary.
*/
if(j0==19) i1 = 0x40000000; else
if(j0==18) i1 = 0x80000000; else
i0 = (i0&(~i))|((0x20000)>>j0);
}
}
} else if (j0>51) {
if(j0==0x400) return x+x; /* inf or NaN */
else return x; /* x is integral */
} else {
i = ((u_int32_t)(0xffffffff))>>(j0-20);
if((i1&i)==0) return x; /* x is integral */
i>>=1;
if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20));
}
INSERT_WORDS(x,i0,i1);
*(volatile double *)&w = TWO52[sx]+x; /* clip any extra precision */
return w-TWO52[sx];
}