glibc/sysdeps/generic/math_private.h

/*
 * ====================================================
 * 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
 */

#ifndef _MATH_PRIVATE_H_
#define _MATH_PRIVATE_H_

#include <endian.h>
#include <stdbool.h>
#include <stdint.h>
#include <sys/types.h>

/* Gather machine dependent _Floatn support.  */
#include <bits/floatn.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 __FLOAT_WORD_ORDER == __BIG_ENDIAN

typedef union
{
  double value;
  struct
  {
    uint32_t msw;
    uint32_t lsw;
  } parts;
  uint64_t word;
} ieee_double_shape_type;

#endif

#if __FLOAT_WORD_ORDER == __LITTLE_ENDIAN

typedef union
{
  double value;
  struct
  {
    uint32_t lsw;
    uint32_t msw;
  } parts;
  uint64_t word;
} 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.  */

#ifndef GET_HIGH_WORD
# define GET_HIGH_WORD(i,d)					\
do {								\
  ieee_double_shape_type gh_u;					\
  gh_u.value = (d);						\
  (i) = gh_u.parts.msw;						\
} while (0)
#endif

/* Get the less significant 32 bit int from a double.  */

#ifndef GET_LOW_WORD
# define GET_LOW_WORD(i,d)					\
do {								\
  ieee_double_shape_type gl_u;					\
  gl_u.value = (d);						\
  (i) = gl_u.parts.lsw;						\
} while (0)
#endif

/* Get all in one, efficient on 64-bit machines.  */
#ifndef EXTRACT_WORDS64
# define EXTRACT_WORDS64(i,d)					\
do {								\
  ieee_double_shape_type gh_u;					\
  gh_u.value = (d);						\
  (i) = gh_u.word;						\
} while (0)
#endif

/* Set a double from two 32 bit ints.  */
#ifndef INSERT_WORDS
# 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)
#endif

/* Get all in one, efficient on 64-bit machines.  */
#ifndef INSERT_WORDS64
# define INSERT_WORDS64(d,i)					\
do {								\
  ieee_double_shape_type iw_u;					\
  iw_u.word = (i);						\
  (d) = iw_u.value;						\
} while (0)
#endif

/* Set the more significant 32 bits of a double from an int.  */
#ifndef SET_HIGH_WORD
#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)
#endif

/* Set the less significant 32 bits of a double from an int.  */
#ifndef SET_LOW_WORD
# 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)
#endif

/* We need to guarantee an expansion of name when building
   ldbl-128 files as another type (e.g _Float128).  */
#define mathx_hidden_def(name) hidden_def(name)

/* Get long double macros from a separate header.  */
#include <math_ldbl.h>

/* Include function declarations for each floating-point.  */
#define _Mdouble_ double
#define _MSUF_
#include <math_private_calls.h>
#undef _MSUF_
#undef _Mdouble_

#define _Mdouble_ float
#define _MSUF_ f
#define __MATH_DECLARING_FLOAT
#include <math_private_calls.h>
#undef __MATH_DECLARING_FLOAT
#undef _MSUF_
#undef _Mdouble_

#define _Mdouble_ long double
#define _MSUF_ l
#define __MATH_DECLARING_LONG_DOUBLE
#include <math_private_calls.h>
#undef __MATH_DECLARING_LONG_DOUBLE
#undef _MSUF_
#undef _Mdouble_

#if __HAVE_DISTINCT_FLOAT128
# define _Mdouble_ _Float128
# define _MSUF_ f128
# define __MATH_DECLARING_FLOATN
# include <math_private_calls.h>
# undef __MATH_DECLARING_FLOATN
# undef _MSUF_
# undef _Mdouble_
#endif

#define NOINLINE __attribute__ ((noinline))

/* Prototypes for functions of the IBM Accurate Mathematical Library.  */
extern double __sin (double __x);
extern double __cos (double __x);
extern int __branred (double __x, double *__a, double *__aa);

#endif /* _MATH_PRIVATE_H_ */