sysdeps/libm-ieee754/e_j1.c

   1 /* @(#)e_j1.c 5.1 93/09/24 */
   2 /*
   3  * ====================================================
   4  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   5  *
   6  * Developed at SunPro, a Sun Microsystems, Inc. business.
   7  * Permission to use, copy, modify, and distribute this
   8  * software is freely granted, provided that this notice
   9  * is preserved.
  10  * ====================================================
  11  */
  12 /* Modified by Naohiko Shimizu/Tokai University, Japan 1997/08/26,
  13    for performance improvement on pipelined processors.
  14 */
  15
  16 #if defined(LIBM_SCCS) && !defined(lint)
  17 static char rcsid[] = "$NetBSD: e_j1.c,v 1.8 1995/05/10 20:45:27 jtc Exp $";
  18 #endif
  19
  20 /* __ieee754_j1(x), __ieee754_y1(x)
  21  * Bessel function of the first and second kinds of order zero.
  22  * Method -- j1(x):
  23  *      1. For tiny x, we use j1(x) = x/2 - x^3/16 + x^5/384 - ...
  24  *      2. Reduce x to |x| since j1(x)=-j1(-x),  and
  25  *         for x in (0,2)
  26  *              j1(x) = x/2 + x*z*R0/S0,  where z = x*x;
  27  *         (precision:  |j1/x - 1/2 - R0/S0 |<2**-61.51 )
  28  *         for x in (2,inf)
  29  *              j1(x) = sqrt(2/(pi*x))*(p1(x)*cos(x1)-q1(x)*sin(x1))
  30  *              y1(x) = sqrt(2/(pi*x))*(p1(x)*sin(x1)+q1(x)*cos(x1))
  31  *         where x1 = x-3*pi/4. It is better to compute sin(x1),cos(x1)
  32  *         as follow:
  33  *              cos(x1) =  cos(x)cos(3pi/4)+sin(x)sin(3pi/4)
  34  *                      =  1/sqrt(2) * (sin(x) - cos(x))
  35  *              sin(x1) =  sin(x)cos(3pi/4)-cos(x)sin(3pi/4)
  36  *                      = -1/sqrt(2) * (sin(x) + cos(x))
  37  *         (To avoid cancellation, use
  38  *              sin(x) +- cos(x) = -cos(2x)/(sin(x) -+ cos(x))
  39  *          to compute the worse one.)
  40  *
  41  *      3 Special cases
  42  *              j1(nan)= nan
  43  *              j1(0) = 0
  44  *              j1(inf) = 0
  45  *
  46  * Method -- y1(x):
  47  *      1. screen out x<=0 cases: y1(0)=-inf, y1(x<0)=NaN
  48  *      2. For x<2.
  49  *         Since
  50  *              y1(x) = 2/pi*(j1(x)*(ln(x/2)+Euler)-1/x-x/2+5/64*x^3-...)
  51  *         therefore y1(x)-2/pi*j1(x)*ln(x)-1/x is an odd function.
  52  *         We use the following function to approximate y1,
  53  *              y1(x) = x*U(z)/V(z) + (2/pi)*(j1(x)*ln(x)-1/x), z= x^2
  54  *         where for x in [0,2] (abs err less than 2**-65.89)
  55  *              U(z) = U0[0] + U0[1]*z + ... + U0[4]*z^4
  56  *              V(z) = 1  + v0[0]*z + ... + v0[4]*z^5
  57  *         Note: For tiny x, 1/x dominate y1 and hence
  58  *              y1(tiny) = -2/pi/tiny, (choose tiny<2**-54)
  59  *      3. For x>=2.
  60  *              y1(x) = sqrt(2/(pi*x))*(p1(x)*sin(x1)+q1(x)*cos(x1))
  61  *         where x1 = x-3*pi/4. It is better to compute sin(x1),cos(x1)
  62  *         by method mentioned above.
  63  */
  64
  65 #include "math.h"
  66 #include "math_private.h"
  67
  68 #ifdef __STDC__
  69 static double pone(double), qone(double);
  70 #else
  71 static double pone(), qone();
  72 #endif
  73
  74 #ifdef __STDC__
  75 static const double
  76 #else
  77 static double
  78 #endif
  79 huge    = 1e300,
  80 one     = 1.0,
  81 invsqrtpi=  5.64189583547756279280e-01, /* 0x3FE20DD7, 0x50429B6D */
  82 tpi      =  6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */
  83         /* R0/S0 on [0,2] */
  84 R[]  = {-6.25000000000000000000e-02, /* 0xBFB00000, 0x00000000 */
  85   1.40705666955189706048e-03, /* 0x3F570D9F, 0x98472C61 */
  86  -1.59955631084035597520e-05, /* 0xBEF0C5C6, 0xBA169668 */
  87   4.96727999609584448412e-08}, /* 0x3E6AAAFA, 0x46CA0BD9 */
  88 S[]  =  {0.0, 1.91537599538363460805e-02, /* 0x3F939D0B, 0x12637E53 */
  89   1.85946785588630915560e-04, /* 0x3F285F56, 0xB9CDF664 */
  90   1.17718464042623683263e-06, /* 0x3EB3BFF8, 0x333F8498 */
  91   5.04636257076217042715e-09, /* 0x3E35AC88, 0xC97DFF2C */
  92   1.23542274426137913908e-11}; /* 0x3DAB2ACF, 0xCFB97ED8 */
  93
  94 #ifdef __STDC__
  95 static const double zero    = 0.0;
  96 #else
  97 static double zero    = 0.0;
  98 #endif
  99
 100 #ifdef __STDC__
 101         double __ieee754_j1(double x)
 102 #else
 103         double __ieee754_j1(x)
 104         double x;
 105 #endif
 106 {
 107         double z, s,c,ss,cc,r,u,v,y,r1,r2,s1,s2,s3,z2,z4;
 108         int32_t hx,ix;
 109
 110         GET_HIGH_WORD(hx,x);
 111         ix = hx&0x7fffffff;
 112         if(ix>=0x7ff00000) return one/x;
 113         y = fabs(x);
 114         if(ix >= 0x40000000) {  /* |x| >= 2.0 */
 115                 s = __sin(y);
 116                 c = __cos(y);
 117                 ss = -s-c;
 118                 cc = s-c;
 119                 if(ix<0x7fe00000) {  /* make sure y+y not overflow */
 120                     z = __cos(y+y);
 121                     if ((s*c)>zero) cc = z/ss;
 122                     else            ss = z/cc;
 123                 }
 124         /*
 125          * j1(x) = 1/sqrt(pi) * (P(1,x)*cc - Q(1,x)*ss) / sqrt(x)
 126          * y1(x) = 1/sqrt(pi) * (P(1,x)*ss + Q(1,x)*cc) / sqrt(x)
 127          */
 128                 if(ix>0x48000000) z = (invsqrtpi*cc)/__sqrt(y);
 129                 else {
 130                     u = pone(y); v = qone(y);
 131                     z = invsqrtpi*(u*cc-v*ss)/__sqrt(y);
 132                 }
 133                 if(hx<0) return -z;
 134                 else     return  z;
 135         }
 136         if(ix<0x3e400000) {     /* |x|<2**-27 */
 137             if(huge+x>one) return 0.5*x;/* inexact if x!=0 necessary */
 138         }
 139         z = x*x;
 140 #ifdef DO_NOT_USE_THIS
 141         r =  z*(r00+z*(r01+z*(r02+z*r03)));
 142         s =  one+z*(s01+z*(s02+z*(s03+z*(s04+z*s05))));
 143         r *= x;
 144 #else
 145         r1 = z*R[0]; z2=z*z;
 146         r2 = R[1]+z*R[2]; z4=z2*z2;
 147         r = r1 + z2*r2 + z4*R[3];
 148         r *= x;
 149         s1 = one+z*S[1];
 150         s2 = S[2]+z*S[3];
 151         s3 = S[4]+z*S[5];
 152         s = s1 + z2*s2 + z4*s3;
 153 #endif
 154         return(x*0.5+r/s);
 155 }
 156
 157 #ifdef __STDC__
 158 static const double U0[5] = {
 159 #else
 160 static double U0[5] = {
 161 #endif
 162  -1.96057090646238940668e-01, /* 0xBFC91866, 0x143CBC8A */
 163   5.04438716639811282616e-02, /* 0x3FA9D3C7, 0x76292CD1 */
 164  -1.91256895875763547298e-03, /* 0xBF5F55E5, 0x4844F50F */
 165   2.35252600561610495928e-05, /* 0x3EF8AB03, 0x8FA6B88E */
 166  -9.19099158039878874504e-08, /* 0xBE78AC00, 0x569105B8 */
 167 };
 168 #ifdef __STDC__
 169 static const double V0[5] = {
 170 #else
 171 static double V0[5] = {
 172 #endif
 173   1.99167318236649903973e-02, /* 0x3F94650D, 0x3F4DA9F0 */
 174   2.02552581025135171496e-04, /* 0x3F2A8C89, 0x6C257764 */
 175   1.35608801097516229404e-06, /* 0x3EB6C05A, 0x894E8CA6 */
 176   6.22741452364621501295e-09, /* 0x3E3ABF1D, 0x5BA69A86 */
 177   1.66559246207992079114e-11, /* 0x3DB25039, 0xDACA772A */
 178 };
 179
 180 #ifdef __STDC__
 181         double __ieee754_y1(double x)
 182 #else
 183         double __ieee754_y1(x)
 184         double x;
 185 #endif
 186 {
 187         double z, s,c,ss,cc,u,v,u1,u2,v1,v2,v3,z2,z4;
 188         int32_t hx,ix,lx;
 189
 190         EXTRACT_WORDS(hx,lx,x);
 191         ix = 0x7fffffff&hx;
 192     /* if Y1(NaN) is NaN, Y1(-inf) is NaN, Y1(inf) is 0 */
 193         if(ix>=0x7ff00000) return  one/(x+x*x);
 194         if((ix|lx)==0) return -one/zero;
 195         if(hx<0) return zero/zero;
 196         if(ix >= 0x40000000) {  /* |x| >= 2.0 */
 197                 s = __sin(x);
 198                 c = __cos(x);
 199                 ss = -s-c;
 200                 cc = s-c;
 201                 if(ix<0x7fe00000) {  /* make sure x+x not overflow */
 202                     z = __cos(x+x);
 203                     if ((s*c)>zero) cc = z/ss;
 204                     else            ss = z/cc;
 205                 }
 206         /* y1(x) = sqrt(2/(pi*x))*(p1(x)*sin(x0)+q1(x)*cos(x0))
 207          * where x0 = x-3pi/4
 208          *      Better formula:
 209          *              cos(x0) = cos(x)cos(3pi/4)+sin(x)sin(3pi/4)
 210          *                      =  1/sqrt(2) * (sin(x) - cos(x))
 211          *              sin(x0) = sin(x)cos(3pi/4)-cos(x)sin(3pi/4)
 212          *                      = -1/sqrt(2) * (cos(x) + sin(x))
 213          * To avoid cancellation, use
 214          *              sin(x) +- cos(x) = -cos(2x)/(sin(x) -+ cos(x))
 215          * to compute the worse one.
 216          */
 217                 if(ix>0x48000000) z = (invsqrtpi*ss)/__sqrt(x);
 218                 else {
 219                     u = pone(x); v = qone(x);
 220                     z = invsqrtpi*(u*ss+v*cc)/__sqrt(x);
 221                 }
 222                 return z;
 223         }
 224         if(ix<=0x3c900000) {    /* x < 2**-54 */
 225             return(-tpi/x);
 226         }
 227         z = x*x;
 228 #ifdef DO_NOT_USE_THIS
 229         u = U0[0]+z*(U0[1]+z*(U0[2]+z*(U0[3]+z*U0[4])));
 230         v = one+z*(V0[0]+z*(V0[1]+z*(V0[2]+z*(V0[3]+z*V0[4]))));
 231 #else
 232         u1 = U0[0]+z*U0[1];z2=z*z;
 233         u2 = U0[2]+z*U0[3];z4=z2*z2;
 234         u  = u1 + z2*u2 + z4*U0[4];
 235         v1 = one+z*V0[0];
 236         v2 = V0[1]+z*V0[2];
 237         v3 = V0[3]+z*V0[4];
 238         v = v1 + z2*v2 + z4*v3;
 239 #endif
 240         return(x*(u/v) + tpi*(__ieee754_j1(x)*__ieee754_log(x)-one/x));
 241 }
 242
 243 /* For x >= 8, the asymptotic expansions of pone is
 244  *      1 + 15/128 s^2 - 4725/2^15 s^4 - ...,   where s = 1/x.
 245  * We approximate pone by
 246  *      pone(x) = 1 + (R/S)
 247  * where  R = pr0 + pr1*s^2 + pr2*s^4 + ... + pr5*s^10
 248  *        S = 1 + ps0*s^2 + ... + ps4*s^10
 249  * and
 250  *      | pone(x)-1-R/S | <= 2  ** ( -60.06)
 251  */
 252
 253 #ifdef __STDC__
 254 static const double pr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
 255 #else
 256 static double pr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
 257 #endif
 258   0.00000000000000000000e+00, /* 0x00000000, 0x00000000 */
 259   1.17187499999988647970e-01, /* 0x3FBDFFFF, 0xFFFFFCCE */
 260   1.32394806593073575129e+01, /* 0x402A7A9D, 0x357F7FCE */
 261   4.12051854307378562225e+02, /* 0x4079C0D4, 0x652EA590 */
 262   3.87474538913960532227e+03, /* 0x40AE457D, 0xA3A532CC */
 263   7.91447954031891731574e+03, /* 0x40BEEA7A, 0xC32782DD */
 264 };
 265 #ifdef __STDC__
 266 static const double ps8[5] = {
 267 #else
 268 static double ps8[5] = {
 269 #endif
 270   1.14207370375678408436e+02, /* 0x405C8D45, 0x8E656CAC */
 271   3.65093083420853463394e+03, /* 0x40AC85DC, 0x964D274F */
 272   3.69562060269033463555e+04, /* 0x40E20B86, 0x97C5BB7F */
 273   9.76027935934950801311e+04, /* 0x40F7D42C, 0xB28F17BB */
 274   3.08042720627888811578e+04, /* 0x40DE1511, 0x697A0B2D */
 275 };
 276
 277 #ifdef __STDC__
 278 static const double pr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
 279 #else
 280 static double pr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
 281 #endif
 282   1.31990519556243522749e-11, /* 0x3DAD0667, 0xDAE1CA7D */
 283   1.17187493190614097638e-01, /* 0x3FBDFFFF, 0xE2C10043 */
 284   6.80275127868432871736e+00, /* 0x401B3604, 0x6E6315E3 */
 285   1.08308182990189109773e+02, /* 0x405B13B9, 0x452602ED */
 286   5.17636139533199752805e+02, /* 0x40802D16, 0xD052D649 */
 287   5.28715201363337541807e+02, /* 0x408085B8, 0xBB7E0CB7 */
 288 };
 289 #ifdef __STDC__
 290 static const double ps5[5] = {
 291 #else
 292 static double ps5[5] = {
 293 #endif
 294   5.92805987221131331921e+01, /* 0x404DA3EA, 0xA8AF633D */
 295   9.91401418733614377743e+02, /* 0x408EFB36, 0x1B066701 */
 296   5.35326695291487976647e+03, /* 0x40B4E944, 0x5706B6FB */
 297   7.84469031749551231769e+03, /* 0x40BEA4B0, 0xB8A5BB15 */
 298   1.50404688810361062679e+03, /* 0x40978030, 0x036F5E51 */
 299 };
 300
 301 #ifdef __STDC__
 302 static const double pr3[6] = {
 303 #else
 304 static double pr3[6] = {/* for x in [4.547,2.8571]=1/[0.2199,0.35001] */
 305 #endif
 306   3.02503916137373618024e-09, /* 0x3E29FC21, 0xA7AD9EDD */
 307   1.17186865567253592491e-01, /* 0x3FBDFFF5, 0x5B21D17B */
 308   3.93297750033315640650e+00, /* 0x400F76BC, 0xE85EAD8A */
 309   3.51194035591636932736e+01, /* 0x40418F48, 0x9DA6D129 */
 310   9.10550110750781271918e+01, /* 0x4056C385, 0x4D2C1837 */
 311   4.85590685197364919645e+01, /* 0x4048478F, 0x8EA83EE5 */
 312 };
 313 #ifdef __STDC__
 314 static const double ps3[5] = {
 315 #else
 316 static double ps3[5] = {
 317 #endif
 318   3.47913095001251519989e+01, /* 0x40416549, 0xA134069C */
 319   3.36762458747825746741e+02, /* 0x40750C33, 0x07F1A75F */
 320   1.04687139975775130551e+03, /* 0x40905B7C, 0x5037D523 */
 321   8.90811346398256432622e+02, /* 0x408BD67D, 0xA32E31E9 */
 322   1.03787932439639277504e+02, /* 0x4059F26D, 0x7C2EED53 */
 323 };
 324
 325 #ifdef __STDC__
 326 static const double pr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
 327 #else
 328 static double pr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
 329 #endif
 330   1.07710830106873743082e-07, /* 0x3E7CE9D4, 0xF65544F4 */
 331   1.17176219462683348094e-01, /* 0x3FBDFF42, 0xBE760D83 */
 332   2.36851496667608785174e+00, /* 0x4002F2B7, 0xF98FAEC0 */
 333   1.22426109148261232917e+01, /* 0x40287C37, 0x7F71A964 */
 334   1.76939711271687727390e+01, /* 0x4031B1A8, 0x177F8EE2 */
 335   5.07352312588818499250e+00, /* 0x40144B49, 0xA574C1FE */
 336 };
 337 #ifdef __STDC__
 338 static const double ps2[5] = {
 339 #else
 340 static double ps2[5] = {
 341 #endif
 342   2.14364859363821409488e+01, /* 0x40356FBD, 0x8AD5ECDC */
 343   1.25290227168402751090e+02, /* 0x405F5293, 0x14F92CD5 */
 344   2.32276469057162813669e+02, /* 0x406D08D8, 0xD5A2DBD9 */
 345   1.17679373287147100768e+02, /* 0x405D6B7A, 0xDA1884A9 */
 346   8.36463893371618283368e+00, /* 0x4020BAB1, 0xF44E5192 */
 347 };
 348
 349 #ifdef __STDC__
 350         static double pone(double x)
 351 #else
 352         static double pone(x)
 353         double x;
 354 #endif
 355 {
 356 #ifdef __STDC__
 357         const double *p,*q;
 358 #else
 359         double *p,*q;
 360 #endif
 361         double z,r,s,r1,r2,r3,s1,s2,s3,z2,z4;
 362         int32_t ix;
 363         GET_HIGH_WORD(ix,x);
 364         ix &= 0x7fffffff;
 365         if(ix>=0x40200000)     {p = pr8; q= ps8;}
 366         else if(ix>=0x40122E8B){p = pr5; q= ps5;}
 367         else if(ix>=0x4006DB6D){p = pr3; q= ps3;}
 368         else if(ix>=0x40000000){p = pr2; q= ps2;}
 369         z = one/(x*x);
 370 #ifdef DO_NOT_USE_THIS
 371         r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 372         s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*q[4]))));
 373 #else
 374         r1 = p[0]+z*p[1]; z2=z*z;
 375         r2 = p[2]+z*p[3]; z4=z2*z2;
 376         r3 = p[4]+z*p[5];
 377         r = r1 + z2*r2 + z4*r3;
 378         s1 = one+z*q[0];
 379         s2 = q[1]+z*q[2];
 380         s3 = q[3]+z*q[4];
 381         s = s1 + z2*s2 + z4*s3;
 382 #endif
 383         return one+ r/s;
 384 }
 385
 386
 387 /* For x >= 8, the asymptotic expansions of qone is
 388  *      3/8 s - 105/1024 s^3 - ..., where s = 1/x.
 389  * We approximate pone by
 390  *      qone(x) = s*(0.375 + (R/S))
 391  * where  R = qr1*s^2 + qr2*s^4 + ... + qr5*s^10
 392  *        S = 1 + qs1*s^2 + ... + qs6*s^12
 393  * and
 394  *      | qone(x)/s -0.375-R/S | <= 2  ** ( -61.13)
 395  */
 396
 397 #ifdef __STDC__
 398 static const double qr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
 399 #else
 400 static double qr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
 401 #endif
 402   0.00000000000000000000e+00, /* 0x00000000, 0x00000000 */
 403  -1.02539062499992714161e-01, /* 0xBFBA3FFF, 0xFFFFFDF3 */
 404  -1.62717534544589987888e+01, /* 0xC0304591, 0xA26779F7 */
 405  -7.59601722513950107896e+02, /* 0xC087BCD0, 0x53E4B576 */
 406  -1.18498066702429587167e+04, /* 0xC0C724E7, 0x40F87415 */
 407  -4.84385124285750353010e+04, /* 0xC0E7A6D0, 0x65D09C6A */
 408 };
 409 #ifdef __STDC__
 410 static const double qs8[6] = {
 411 #else
 412 static double qs8[6] = {
 413 #endif
 414   1.61395369700722909556e+02, /* 0x40642CA6, 0xDE5BCDE5 */
 415   7.82538599923348465381e+03, /* 0x40BE9162, 0xD0D88419 */
 416   1.33875336287249578163e+05, /* 0x4100579A, 0xB0B75E98 */
 417   7.19657723683240939863e+05, /* 0x4125F653, 0x72869C19 */
 418   6.66601232617776375264e+05, /* 0x412457D2, 0x7719AD5C */
 419  -2.94490264303834643215e+05, /* 0xC111F969, 0x0EA5AA18 */
 420 };
 421
 422 #ifdef __STDC__
 423 static const double qr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
 424 #else
 425 static double qr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
 426 #endif
 427  -2.08979931141764104297e-11, /* 0xBDB6FA43, 0x1AA1A098 */
 428  -1.02539050241375426231e-01, /* 0xBFBA3FFF, 0xCB597FEF */
 429  -8.05644828123936029840e+00, /* 0xC0201CE6, 0xCA03AD4B */
 430  -1.83669607474888380239e+02, /* 0xC066F56D, 0x6CA7B9B0 */
 431  -1.37319376065508163265e+03, /* 0xC09574C6, 0x6931734F */
 432  -2.61244440453215656817e+03, /* 0xC0A468E3, 0x88FDA79D */
 433 };
 434 #ifdef __STDC__
 435 static const double qs5[6] = {
 436 #else
 437 static double qs5[6] = {
 438 #endif
 439   8.12765501384335777857e+01, /* 0x405451B2, 0xFF5A11B2 */
 440   1.99179873460485964642e+03, /* 0x409F1F31, 0xE77BF839 */
 441   1.74684851924908907677e+04, /* 0x40D10F1F, 0x0D64CE29 */
 442   4.98514270910352279316e+04, /* 0x40E8576D, 0xAABAD197 */
 443   2.79480751638918118260e+04, /* 0x40DB4B04, 0xCF7C364B */
 444  -4.71918354795128470869e+03, /* 0xC0B26F2E, 0xFCFFA004 */
 445 };
 446
 447 #ifdef __STDC__
 448 static const double qr3[6] = {
 449 #else
 450 static double qr3[6] = {/* for x in [4.547,2.8571]=1/[0.2199,0.35001] */
 451 #endif
 452  -5.07831226461766561369e-09, /* 0xBE35CFA9, 0xD38FC84F */
 453  -1.02537829820837089745e-01, /* 0xBFBA3FEB, 0x51AEED54 */
 454  -4.61011581139473403113e+00, /* 0xC01270C2, 0x3302D9FF */
 455  -5.78472216562783643212e+01, /* 0xC04CEC71, 0xC25D16DA */
 456  -2.28244540737631695038e+02, /* 0xC06C87D3, 0x4718D55F */
 457  -2.19210128478909325622e+02, /* 0xC06B66B9, 0x5F5C1BF6 */
 458 };
 459 #ifdef __STDC__
 460 static const double qs3[6] = {
 461 #else
 462 static double qs3[6] = {
 463 #endif
 464   4.76651550323729509273e+01, /* 0x4047D523, 0xCCD367E4 */
 465   6.73865112676699709482e+02, /* 0x40850EEB, 0xC031EE3E */
 466   3.38015286679526343505e+03, /* 0x40AA684E, 0x448E7C9A */
 467   5.54772909720722782367e+03, /* 0x40B5ABBA, 0xA61D54A6 */
 468   1.90311919338810798763e+03, /* 0x409DBC7A, 0x0DD4DF4B */
 469  -1.35201191444307340817e+02, /* 0xC060E670, 0x290A311F */
 470 };
 471
 472 #ifdef __STDC__
 473 static const double qr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
 474 #else
 475 static double qr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
 476 #endif
 477  -1.78381727510958865572e-07, /* 0xBE87F126, 0x44C626D2 */
 478  -1.02517042607985553460e-01, /* 0xBFBA3E8E, 0x9148B010 */
 479  -2.75220568278187460720e+00, /* 0xC0060484, 0x69BB4EDA */
 480  -1.96636162643703720221e+01, /* 0xC033A9E2, 0xC168907F */
 481  -4.23253133372830490089e+01, /* 0xC04529A3, 0xDE104AAA */
 482  -2.13719211703704061733e+01, /* 0xC0355F36, 0x39CF6E52 */
 483 };
 484 #ifdef __STDC__
 485 static const double qs2[6] = {
 486 #else
 487 static double qs2[6] = {
 488 #endif
 489   2.95333629060523854548e+01, /* 0x403D888A, 0x78AE64FF */
 490   2.52981549982190529136e+02, /* 0x406F9F68, 0xDB821CBA */
 491   7.57502834868645436472e+02, /* 0x4087AC05, 0xCE49A0F7 */
 492   7.39393205320467245656e+02, /* 0x40871B25, 0x48D4C029 */
 493   1.55949003336666123687e+02, /* 0x40637E5E, 0x3C3ED8D4 */
 494  -4.95949898822628210127e+00, /* 0xC013D686, 0xE71BE86B */
 495 };
 496
 497 #ifdef __STDC__
 498         static double qone(double x)
 499 #else
 500         static double qone(x)
 501         double x;
 502 #endif
 503 {
 504 #ifdef __STDC__
 505         const double *p,*q;
 506 #else
 507         double *p,*q;
 508 #endif
 509         double  s,r,z,r1,r2,r3,s1,s2,s3,z2,z4,z6;
 510         int32_t ix;
 511         GET_HIGH_WORD(ix,x);
 512         ix &= 0x7fffffff;
 513         if(ix>=0x40200000)     {p = qr8; q= qs8;}
 514         else if(ix>=0x40122E8B){p = qr5; q= qs5;}
 515         else if(ix>=0x4006DB6D){p = qr3; q= qs3;}
 516         else if(ix>=0x40000000){p = qr2; q= qs2;}
 517         z = one/(x*x);
 518 #ifdef DO_NOT_USE_THIS
 519         r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 520         s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
 521 #else
 522         r1 = p[0]+z*p[1]; z2=z*z;
 523         r2 = p[2]+z*p[3]; z4=z2*z2;
 524         r3 = p[4]+z*p[5]; z6=z4*z2;
 525         r = r1 + z2*r2 + z4*r3;
 526         s1 = one+z*q[0];
 527         s2 = q[1]+z*q[2];
 528         s3 = q[3]+z*q[4];
 529         s = s1 + z2*s2 + z4*s3 + z6*q[5];
 530 #endif
 531         return (.375 + r/s)/x;
 532 }