/*
 * from: @(#)fdlibm.h 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 _S_RINT_H_
#define _S_RINT_H_

#include "gmt_config.h"

#ifdef HAVE_SYS_TYPES_H_
#	include <sys/types.h>
#endif

/* Suppress Visual Studio warnings */
#ifdef _MSC_VER
#	pragma warning( disable : 4146 )
#endif

/*
 * 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.
 */

#ifdef WORDS_BIGENDIAN

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

#else /* WORDS_BIGENDIAN */

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

#endif /* WORDS_BIGENDIAN */

/* 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)

#endif /* !_S_RINT_H_ */
