CocoRoboDesktop/pdf1.js/node_modules/cephes/cephes/isnan.c

/*							isnan()
 *							signbit()
 *							isfinite()
 *
 *	Floating point numeric utilities
 *
 *
 *
 * SYNOPSIS:
 *
 * double ceil(), floor(), frexp(), ldexp();
 * int signbit(), isnan(), isfinite();
 * double x, y;
 * int expnt, n;
 *
 * y = floor(x);
 * y = ceil(x);
 * y = frexp( x, &expnt );
 * y = ldexp( x, n );
 * n = signbit(x);
 * n = isnan(x);
 * n = isfinite(x);
 *
 *
 *
 * DESCRIPTION:
 *
 * All four routines return a double precision floating point
 * result.
 *
 * floor() returns the largest integer less than or equal to x.
 * It truncates toward minus infinity.
 *
 * ceil() returns the smallest integer greater than or equal
 * to x.  It truncates toward plus infinity.
 *
 * frexp() extracts the exponent from x.  It returns an integer
 * power of two to expnt and the significand between 0.5 and 1
 * to y.  Thus  x = y * 2**expn.
 *
 * ldexp() multiplies x by 2**n.
 *
 * signbit(x) returns 1 if the sign bit of x is 1, else 0.
 *
 * These functions are part of the standard C run time library
 * for many but not all C compilers.  The ones supplied are
 * written in C for either DEC or IEEE arithmetic.  They should
 * be used only if your compiler library does not already have
 * them.
 *
 * The IEEE versions assume that denormal numbers are implemented
 * in the arithmetic.  Some modifications will be required if
 * the arithmetic has abrupt rather than gradual underflow.
 */

/*
Cephes Math Library Release 2.3:  March, 1995
Copyright 1984, 1995 by Stephen L. Moshier
*/

#include "mconf.h"

#ifdef UNK
/* ceil(), floor(), frexp(), ldexp() may need to be rewritten. */
#undef UNK
#if BIGENDIAN
#define MIEEE 1
#else
#define IBMPC 1
#endif
#endif

/* Return 1 if the sign bit of x is 1, else 0.  */

int signbit(x) double x;
{
  union {
    double d;
    short s[4];
    int i[2];
  } u;

  u.d = x;

  if (sizeof(int) == 4) {
#ifdef IBMPC
    return (u.i[1] < 0);
#endif
#ifdef DEC
    return (u.s[3] < 0);
#endif
#ifdef MIEEE
    return (u.i[0] < 0);
#endif
  } else {
#ifdef IBMPC
    return (u.s[3] < 0);
#endif
#ifdef DEC
    return (u.s[3] < 0);
#endif
#ifdef MIEEE
    return (u.s[0] < 0);
#endif
  }
}

/* Return 1 if x is a number that is Not a Number, else return 0.  */

int isnan(x) double x;
{
#ifdef NANS
  union {
    double d;
    unsigned short s[4];
    unsigned int i[2];
  } u;

  u.d = x;

  if (sizeof(int) == 4) {
#ifdef IBMPC
    if (((u.i[1] & 0x7ff00000) == 0x7ff00000) &&
        (((u.i[1] & 0x000fffff) != 0) || (u.i[0] != 0)))
      return 1;
#endif
#ifdef DEC
    if ((u.s[1] & 0x7fff) == 0) {
      if ((u.s[2] | u.s[1] | u.s[0]) != 0)
        return (1);
    }
#endif
#ifdef MIEEE
    if (((u.i[0] & 0x7ff00000) == 0x7ff00000) &&
        (((u.i[0] & 0x000fffff) != 0) || (u.i[1] != 0)))
      return 1;
#endif
    return (0);
  } else { /* size int not 4 */
#ifdef IBMPC
    if ((u.s[3] & 0x7ff0) == 0x7ff0) {
      if (((u.s[3] & 0x000f) | u.s[2] | u.s[1] | u.s[0]) != 0)
        return (1);
    }
#endif
#ifdef DEC
    if ((u.s[3] & 0x7fff) == 0) {
      if ((u.s[2] | u.s[1] | u.s[0]) != 0)
        return (1);
    }
#endif
#ifdef MIEEE
    if ((u.s[0] & 0x7ff0) == 0x7ff0) {
      if (((u.s[0] & 0x000f) | u.s[1] | u.s[2] | u.s[3]) != 0)
        return (1);
    }
#endif
    return (0);
  } /* size int not 4 */

#else
  /* No NANS.  */
  return (0);
#endif
}

/* Return 1 if x is not infinite and is not a NaN.  */

int isfinite(x) double x;
{
#ifdef INFINITIES
  union {
    double d;
    unsigned short s[4];
    unsigned int i[2];
  } u;

  u.d = x;

  if (sizeof(int) == 4) {
#ifdef IBMPC
    if ((u.i[1] & 0x7ff00000) != 0x7ff00000)
      return 1;
#endif
#ifdef DEC
    if ((u.s[3] & 0x7fff) != 0)
      return 1;
#endif
#ifdef MIEEE
    if ((u.i[0] & 0x7ff00000) != 0x7ff00000)
      return 1;
#endif
    return (0);
  } else {
#ifdef IBMPC
    if ((u.s[3] & 0x7ff0) != 0x7ff0)
      return 1;
#endif
#ifdef DEC
    if ((u.s[3] & 0x7fff) != 0)
      return 1;
#endif
#ifdef MIEEE
    if ((u.s[0] & 0x7ff0) != 0x7ff0)
      return 1;
#endif
    return (0);
  }
#else
  /* No INFINITY.  */
  return (1);
#endif
}