CocoRoboDesktop/pdf.js/node_modules/cephes/cephes/exp10.c

/*							exp10.c
 *
 *	Base 10 exponential function
 *      (Common antilogarithm)
 *
 *
 *
 * SYNOPSIS:
 *
 * double x, y, exp10();
 *
 * y = exp10( x );
 *
 *
 *
 * DESCRIPTION:
 *
 * Returns 10 raised to the x power.
 *
 * Range reduction is accomplished by expressing the argument
 * as 10**x = 2**n 10**f, with |f| < 0.5 log10(2).
 * The Pade' form
 *
 *    1 + 2x P(x**2)/( Q(x**2) - P(x**2) )
 *
 * is used to approximate 10**f.
 *
 *
 *
 * ACCURACY:
 *
 *                      Relative error:
 * arithmetic   domain     # trials      peak         rms
 *    IEEE     -307,+307    30000       2.2e-16     5.5e-17
 * Test result from an earlier version (2.1):
 *    DEC       -38,+38     70000       3.1e-17     7.0e-18
 *
 * ERROR MESSAGES:
 *
 *   message         condition      value returned
 * exp10 underflow    x < -MAXL10        0.0
 * exp10 overflow     x > MAXL10       MAXNUM
 *
 * DEC arithmetic: MAXL10 = 38.230809449325611792.
 * IEEE arithmetic: MAXL10 = 308.2547155599167.
 *
 */

/*
Cephes Math Library Release 2.8:  June, 2000
Copyright 1984, 1991, 2000 by Stephen L. Moshier
*/

#include "mconf.h"

#ifdef UNK
static double P[] = {
    4.09962519798587023075E-2,
    1.17452732554344059015E1,
    4.06717289936872725516E2,
    2.39423741207388267439E3,
};
static double Q[] = {
    /* 1.00000000000000000000E0,*/
    8.50936160849306532625E1,
    1.27209271178345121210E3,
    2.07960819286001865907E3,
};
/* static double LOG102 = 3.01029995663981195214e-1; */
static double LOG210 = 3.32192809488736234787e0;
static double LG102A = 3.01025390625000000000E-1;
static double LG102B = 4.60503898119521373889E-6;
/* static double MAXL10 = 38.230809449325611792; */
static double MAXL10 = 308.2547155599167;
#endif

#ifdef DEC
static unsigned short P[] = {
    0037047, 0165657, 0114061, 0067234, 0041073, 0166243, 0123052, 0144643,
    0042313, 0055720, 0024032, 0047443, 0043025, 0121714, 0070232, 0050007,
};
static unsigned short Q[] = {
    /*0040200,0000000,0000000,0000000,*/
    0041652, 0027756, 0071216, 0050075, 0042637, 0001367,
    0077263, 0136017, 0043001, 0174673, 0024157, 0133416,
};
/*
static unsigned short L102[] = {0037632,0020232,0102373,0147770};
#define LOG102 *(double *)L102
*/
static unsigned short L210[] = {0040524, 0115170, 0045715, 0015613};
#define LOG210 *(double *)L210
static unsigned short L102A[] = {
    0037632,
    0020000,
    0000000,
    0000000,
};
#define LG102A *(double *)L102A
static unsigned short L102B[] = {
    0033632,
    0102373,
    0147767,
    0114220,
};
#define LG102B *(double *)L102B
static unsigned short MXL[] = {
    0041430,
    0166131,
    0047761,
    0154130,
};
#define MAXL10 (*(double *)MXL)
#endif

#ifdef IBMPC
static unsigned short P[] = {
    0x2dd4, 0xf306, 0xfd75, 0x3fa4, 0x5934, 0x74c5, 0x7d94, 0x4027,
    0x49e4, 0x0503, 0x6b7a, 0x4079, 0x4a01, 0x8e13, 0xb479, 0x40a2,
};
static unsigned short Q[] = {
    /*0x0000,0x0000,0x0000,0x3ff0,*/
    0xca08, 0xce51, 0x45fd, 0x4055, 0x7782, 0xefd6,
    0xe05e, 0x4093, 0xf6e2, 0x650d, 0x3f37, 0x40a0,
};
/*
static unsigned short L102[] = {0x79ff,0x509f,0x4413,0x3fd3};
#define LOG102 *(double *)L102
*/
static unsigned short L210[] = {0xa371, 0x0979, 0x934f, 0x400a};
#define LOG210 *(double *)L210
static unsigned short L102A[] = {
    0x0000,
    0x0000,
    0x4400,
    0x3fd3,
};
#define LG102A *(double *)L102A
static unsigned short L102B[] = {
    0xf312,
    0x79fe,
    0x509f,
    0x3ed3,
};
#define LG102B *(double *)L102B
static double MAXL10 = 308.2547155599167;
#endif

#ifdef MIEEE
static unsigned short P[] = {
    0x3fa4, 0xfd75, 0xf306, 0x2dd4, 0x4027, 0x7d94, 0x74c5, 0x5934,
    0x4079, 0x6b7a, 0x0503, 0x49e4, 0x40a2, 0xb479, 0x8e13, 0x4a01,
};
static unsigned short Q[] = {
    /*0x3ff0,0x0000,0x0000,0x0000,*/
    0x4055, 0x45fd, 0xce51, 0xca08, 0x4093, 0xe05e,
    0xefd6, 0x7782, 0x40a0, 0x3f37, 0x650d, 0xf6e2,
};
/*
static unsigned short L102[] = {0x3fd3,0x4413,0x509f,0x79ff};
#define LOG102 *(double *)L102
*/
static unsigned short L210[] = {0x400a, 0x934f, 0x0979, 0xa371};
#define LOG210 *(double *)L210
static unsigned short L102A[] = {
    0x3fd3,
    0x4400,
    0x0000,
    0x0000,
};
#define LG102A *(double *)L102A
static unsigned short L102B[] = {
    0x3ed3,
    0x509f,
    0x79fe,
    0xf312,
};
#define LG102B *(double *)L102B
static double MAXL10 = 308.2547155599167;
#endif

#ifdef ANSIPROT
extern double floor(double);
extern double ldexp(double, int);
extern double polevl(double, void *, int);
extern double p1evl(double, void *, int);
extern int isnan(double);
extern int isfinite(double);
#else
double floor(), ldexp(), polevl(), p1evl();
int isnan(), isfinite();
#endif
extern double MAXNUM;
#ifdef INFINITIES
extern double INFINITY;
#endif

double exp10(x) double x;
{
  double px, xx;
  short n;

#ifdef NANS
  if (isnan(x))
    return (x);
#endif
  if (x > MAXL10) {
#ifdef INFINITIES
    return (INFINITY);
#else
    mtherr("exp10", OVERFLOW);
    return (MAXNUM);
#endif
  }

  if (x < -MAXL10) /* Would like to use MINLOG but can't */
  {
#ifndef INFINITIES
    mtherr("exp10", UNDERFLOW);
#endif
    return (0.0);
  }

  /* Express 10**x = 10**g 2**n
   *   = 10**g 10**( n log10(2) )
   *   = 10**( g + n log10(2) )
   */
  px = floor(LOG210 * x + 0.5);
  n = px;
  x -= px * LG102A;
  x -= px * LG102B;

  /* rational approximation for exponential
   * of the fractional part:
   * 10**x = 1 + 2x P(x**2)/( Q(x**2) - P(x**2) )
   */
  xx = x * x;
  px = x * polevl(xx, P, 3);
  x = px / (p1evl(xx, Q, 3) - px);
  x = 1.0 + ldexp(x, 1);

  /* multiply by power of 2 */
  x = ldexp(x, n);

  return (x);
}