/*

 * ====================================================

 * 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

 * $Id: math_private.h 1969 2006-02-24 09:57:14Z slouken $

 */

#ifndef _MATH_PRIVATE_H_

#define _MATH_PRIVATE_H_

#include "SDL_name.h"

#include "SDL_endian.h"

#define huge		really_big /* huge is a reserved keyword in VC++ 6.0 */

#define u_int32_t	uint32_t

/* 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.  */

/*

 * Math on arm is special:

 * For FPA, float words are always big-endian.

 * For VFP, floats words follow the memory system mode.

 */

#if (SDL_BYTEORDER == SDL_BIG_ENDIAN) || \

    (!defined(__VFP_FP__) && (defined(__arm__) || defined(__thumb__)))

typedef union

{

  double value;

  struct

  {

    u_int32_t msw;

    u_int32_t lsw;

  } parts;

} ieee_double_shape_type;

#else

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;

  u_int32_t 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 __STDC__

static const double

#else

static double

#endif

zero    =  0.0,

one	=  1.0,

two	=  2.0,

two53	=  9007199254740992.0,	/* 0x43400000, 0x00000000 */

two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */

twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */

huge   = 1.0e+300,

tiny   = 1.0e-300;

#endif /* _MATH_PRIVATE_H_ */