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[glibc.git] / sysdeps / libm-ieee754 / e_j1f.c
blobe6f14a16ac1b49f3507d92e3b0afbfd12c7eb7ca
1 /* e_j1f.c -- float version of e_j1.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
5 /*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
16 #if defined(LIBM_SCCS) && !defined(lint)
17 static char rcsid[] = "$NetBSD: e_j1f.c,v 1.4 1995/05/10 20:45:31 jtc Exp $";
18 #endif
20 #include "math.h"
21 #include "math_private.h"
23 #ifdef __STDC__
24 static float ponef(float), qonef(float);
25 #else
26 static float ponef(), qonef();
27 #endif
29 #ifdef __STDC__
30 static const float
31 #else
32 static float
33 #endif
34 huge = 1e30,
35 one = 1.0,
36 invsqrtpi= 5.6418961287e-01, /* 0x3f106ebb */
37 tpi = 6.3661974669e-01, /* 0x3f22f983 */
38 /* R0/S0 on [0,2] */
39 r00 = -6.2500000000e-02, /* 0xbd800000 */
40 r01 = 1.4070566976e-03, /* 0x3ab86cfd */
41 r02 = -1.5995563444e-05, /* 0xb7862e36 */
42 r03 = 4.9672799207e-08, /* 0x335557d2 */
43 s01 = 1.9153760746e-02, /* 0x3c9ce859 */
44 s02 = 1.8594678841e-04, /* 0x3942fab6 */
45 s03 = 1.1771846857e-06, /* 0x359dffc2 */
46 s04 = 5.0463624390e-09, /* 0x31ad6446 */
47 s05 = 1.2354227016e-11; /* 0x2d59567e */
49 #ifdef __STDC__
50 static const float zero = 0.0;
51 #else
52 static float zero = 0.0;
53 #endif
55 #ifdef __STDC__
56 float __ieee754_j1f(float x)
57 #else
58 float __ieee754_j1f(x)
59 float x;
60 #endif
62 float z, s,c,ss,cc,r,u,v,y;
63 int32_t hx,ix;
65 GET_FLOAT_WORD(hx,x);
66 ix = hx&0x7fffffff;
67 if(ix>=0x7f800000) return one/x;
68 y = fabsf(x);
69 if(ix >= 0x40000000) { /* |x| >= 2.0 */
70 s = __sinf(y);
71 c = __cosf(y);
72 ss = -s-c;
73 cc = s-c;
74 if(ix<0x7f000000) { /* make sure y+y not overflow */
75 z = __cosf(y+y);
76 if ((s*c)>zero) cc = z/ss;
77 else ss = z/cc;
80 * j1(x) = 1/sqrt(pi) * (P(1,x)*cc - Q(1,x)*ss) / sqrt(x)
81 * y1(x) = 1/sqrt(pi) * (P(1,x)*ss + Q(1,x)*cc) / sqrt(x)
83 if(ix>0x48000000) z = (invsqrtpi*cc)/__sqrtf(y);
84 else {
85 u = ponef(y); v = qonef(y);
86 z = invsqrtpi*(u*cc-v*ss)/__sqrtf(y);
88 if(hx<0) return -z;
89 else return z;
91 if(ix<0x32000000) { /* |x|<2**-27 */
92 if(huge+x>one) return (float)0.5*x;/* inexact if x!=0 necessary */
94 z = x*x;
95 r = z*(r00+z*(r01+z*(r02+z*r03)));
96 s = one+z*(s01+z*(s02+z*(s03+z*(s04+z*s05))));
97 r *= x;
98 return(x*(float)0.5+r/s);
101 #ifdef __STDC__
102 static const float U0[5] = {
103 #else
104 static float U0[5] = {
105 #endif
106 -1.9605709612e-01, /* 0xbe48c331 */
107 5.0443872809e-02, /* 0x3d4e9e3c */
108 -1.9125689287e-03, /* 0xbafaaf2a */
109 2.3525259166e-05, /* 0x37c5581c */
110 -9.1909917899e-08, /* 0xb3c56003 */
112 #ifdef __STDC__
113 static const float V0[5] = {
114 #else
115 static float V0[5] = {
116 #endif
117 1.9916731864e-02, /* 0x3ca3286a */
118 2.0255257550e-04, /* 0x3954644b */
119 1.3560879779e-06, /* 0x35b602d4 */
120 6.2274145840e-09, /* 0x31d5f8eb */
121 1.6655924903e-11, /* 0x2d9281cf */
124 #ifdef __STDC__
125 float __ieee754_y1f(float x)
126 #else
127 float __ieee754_y1f(x)
128 float x;
129 #endif
131 float z, s,c,ss,cc,u,v;
132 int32_t hx,ix;
134 GET_FLOAT_WORD(hx,x);
135 ix = 0x7fffffff&hx;
136 /* if Y1(NaN) is NaN, Y1(-inf) is NaN, Y1(inf) is 0 */
137 if(ix>=0x7f800000) return one/(x+x*x);
138 if(ix==0) return -one/zero;
139 if(hx<0) return zero/zero;
140 if(ix >= 0x40000000) { /* |x| >= 2.0 */
141 s = __sinf(x);
142 c = __cosf(x);
143 ss = -s-c;
144 cc = s-c;
145 if(ix<0x7f000000) { /* make sure x+x not overflow */
146 z = __cosf(x+x);
147 if ((s*c)>zero) cc = z/ss;
148 else ss = z/cc;
150 /* y1(x) = sqrt(2/(pi*x))*(p1(x)*sin(x0)+q1(x)*cos(x0))
151 * where x0 = x-3pi/4
152 * Better formula:
153 * cos(x0) = cos(x)cos(3pi/4)+sin(x)sin(3pi/4)
154 * = 1/sqrt(2) * (sin(x) - cos(x))
155 * sin(x0) = sin(x)cos(3pi/4)-cos(x)sin(3pi/4)
156 * = -1/sqrt(2) * (cos(x) + sin(x))
157 * To avoid cancellation, use
158 * sin(x) +- cos(x) = -cos(2x)/(sin(x) -+ cos(x))
159 * to compute the worse one.
161 if(ix>0x48000000) z = (invsqrtpi*ss)/__sqrtf(x);
162 else {
163 u = ponef(x); v = qonef(x);
164 z = invsqrtpi*(u*ss+v*cc)/__sqrtf(x);
166 return z;
168 if(ix<=0x24800000) { /* x < 2**-54 */
169 return(-tpi/x);
171 z = x*x;
172 u = U0[0]+z*(U0[1]+z*(U0[2]+z*(U0[3]+z*U0[4])));
173 v = one+z*(V0[0]+z*(V0[1]+z*(V0[2]+z*(V0[3]+z*V0[4]))));
174 return(x*(u/v) + tpi*(__ieee754_j1f(x)*__ieee754_logf(x)-one/x));
177 /* For x >= 8, the asymptotic expansions of pone is
178 * 1 + 15/128 s^2 - 4725/2^15 s^4 - ..., where s = 1/x.
179 * We approximate pone by
180 * pone(x) = 1 + (R/S)
181 * where R = pr0 + pr1*s^2 + pr2*s^4 + ... + pr5*s^10
182 * S = 1 + ps0*s^2 + ... + ps4*s^10
183 * and
184 * | pone(x)-1-R/S | <= 2 ** ( -60.06)
187 #ifdef __STDC__
188 static const float pr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
189 #else
190 static float pr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
191 #endif
192 0.0000000000e+00, /* 0x00000000 */
193 1.1718750000e-01, /* 0x3df00000 */
194 1.3239480972e+01, /* 0x4153d4ea */
195 4.1205184937e+02, /* 0x43ce06a3 */
196 3.8747453613e+03, /* 0x45722bed */
197 7.9144794922e+03, /* 0x45f753d6 */
199 #ifdef __STDC__
200 static const float ps8[5] = {
201 #else
202 static float ps8[5] = {
203 #endif
204 1.1420736694e+02, /* 0x42e46a2c */
205 3.6509309082e+03, /* 0x45642ee5 */
206 3.6956207031e+04, /* 0x47105c35 */
207 9.7602796875e+04, /* 0x47bea166 */
208 3.0804271484e+04, /* 0x46f0a88b */
211 #ifdef __STDC__
212 static const float pr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
213 #else
214 static float pr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
215 #endif
216 1.3199052094e-11, /* 0x2d68333f */
217 1.1718749255e-01, /* 0x3defffff */
218 6.8027510643e+00, /* 0x40d9b023 */
219 1.0830818176e+02, /* 0x42d89dca */
220 5.1763616943e+02, /* 0x440168b7 */
221 5.2871520996e+02, /* 0x44042dc6 */
223 #ifdef __STDC__
224 static const float ps5[5] = {
225 #else
226 static float ps5[5] = {
227 #endif
228 5.9280597687e+01, /* 0x426d1f55 */
229 9.9140142822e+02, /* 0x4477d9b1 */
230 5.3532670898e+03, /* 0x45a74a23 */
231 7.8446904297e+03, /* 0x45f52586 */
232 1.5040468750e+03, /* 0x44bc0180 */
235 #ifdef __STDC__
236 static const float pr3[6] = {
237 #else
238 static float pr3[6] = {/* for x in [4.547,2.8571]=1/[0.2199,0.35001] */
239 #endif
240 3.0250391081e-09, /* 0x314fe10d */
241 1.1718686670e-01, /* 0x3defffab */
242 3.9329774380e+00, /* 0x407bb5e7 */
243 3.5119403839e+01, /* 0x420c7a45 */
244 9.1055007935e+01, /* 0x42b61c2a */
245 4.8559066772e+01, /* 0x42423c7c */
247 #ifdef __STDC__
248 static const float ps3[5] = {
249 #else
250 static float ps3[5] = {
251 #endif
252 3.4791309357e+01, /* 0x420b2a4d */
253 3.3676245117e+02, /* 0x43a86198 */
254 1.0468714600e+03, /* 0x4482dbe3 */
255 8.9081134033e+02, /* 0x445eb3ed */
256 1.0378793335e+02, /* 0x42cf936c */
259 #ifdef __STDC__
260 static const float pr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
261 #else
262 static float pr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
263 #endif
264 1.0771083225e-07, /* 0x33e74ea8 */
265 1.1717621982e-01, /* 0x3deffa16 */
266 2.3685150146e+00, /* 0x401795c0 */
267 1.2242610931e+01, /* 0x4143e1bc */
268 1.7693971634e+01, /* 0x418d8d41 */
269 5.0735230446e+00, /* 0x40a25a4d */
271 #ifdef __STDC__
272 static const float ps2[5] = {
273 #else
274 static float ps2[5] = {
275 #endif
276 2.1436485291e+01, /* 0x41ab7dec */
277 1.2529022980e+02, /* 0x42fa9499 */
278 2.3227647400e+02, /* 0x436846c7 */
279 1.1767937469e+02, /* 0x42eb5bd7 */
280 8.3646392822e+00, /* 0x4105d590 */
283 #ifdef __STDC__
284 static float ponef(float x)
285 #else
286 static float ponef(x)
287 float x;
288 #endif
290 #ifdef __STDC__
291 const float *p,*q;
292 #else
293 float *p,*q;
294 #endif
295 float z,r,s;
296 int32_t ix;
297 GET_FLOAT_WORD(ix,x);
298 ix &= 0x7fffffff;
299 if(ix>=0x41000000) {p = pr8; q= ps8;}
300 else if(ix>=0x40f71c58){p = pr5; q= ps5;}
301 else if(ix>=0x4036db68){p = pr3; q= ps3;}
302 else if(ix>=0x40000000){p = pr2; q= ps2;}
303 z = one/(x*x);
304 r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
305 s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*q[4]))));
306 return one+ r/s;
310 /* For x >= 8, the asymptotic expansions of qone is
311 * 3/8 s - 105/1024 s^3 - ..., where s = 1/x.
312 * We approximate pone by
313 * qone(x) = s*(0.375 + (R/S))
314 * where R = qr1*s^2 + qr2*s^4 + ... + qr5*s^10
315 * S = 1 + qs1*s^2 + ... + qs6*s^12
316 * and
317 * | qone(x)/s -0.375-R/S | <= 2 ** ( -61.13)
320 #ifdef __STDC__
321 static const float qr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
322 #else
323 static float qr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
324 #endif
325 0.0000000000e+00, /* 0x00000000 */
326 -1.0253906250e-01, /* 0xbdd20000 */
327 -1.6271753311e+01, /* 0xc1822c8d */
328 -7.5960174561e+02, /* 0xc43de683 */
329 -1.1849806641e+04, /* 0xc639273a */
330 -4.8438511719e+04, /* 0xc73d3683 */
332 #ifdef __STDC__
333 static const float qs8[6] = {
334 #else
335 static float qs8[6] = {
336 #endif
337 1.6139537048e+02, /* 0x43216537 */
338 7.8253862305e+03, /* 0x45f48b17 */
339 1.3387534375e+05, /* 0x4802bcd6 */
340 7.1965775000e+05, /* 0x492fb29c */
341 6.6660125000e+05, /* 0x4922be94 */
342 -2.9449025000e+05, /* 0xc88fcb48 */
345 #ifdef __STDC__
346 static const float qr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
347 #else
348 static float qr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
349 #endif
350 -2.0897993405e-11, /* 0xadb7d219 */
351 -1.0253904760e-01, /* 0xbdd1fffe */
352 -8.0564479828e+00, /* 0xc100e736 */
353 -1.8366960144e+02, /* 0xc337ab6b */
354 -1.3731937256e+03, /* 0xc4aba633 */
355 -2.6124443359e+03, /* 0xc523471c */
357 #ifdef __STDC__
358 static const float qs5[6] = {
359 #else
360 static float qs5[6] = {
361 #endif
362 8.1276550293e+01, /* 0x42a28d98 */
363 1.9917987061e+03, /* 0x44f8f98f */
364 1.7468484375e+04, /* 0x468878f8 */
365 4.9851425781e+04, /* 0x4742bb6d */
366 2.7948074219e+04, /* 0x46da5826 */
367 -4.7191835938e+03, /* 0xc5937978 */
370 #ifdef __STDC__
371 static const float qr3[6] = {
372 #else
373 static float qr3[6] = {/* for x in [4.547,2.8571]=1/[0.2199,0.35001] */
374 #endif
375 -5.0783124372e-09, /* 0xb1ae7d4f */
376 -1.0253783315e-01, /* 0xbdd1ff5b */
377 -4.6101160049e+00, /* 0xc0938612 */
378 -5.7847221375e+01, /* 0xc267638e */
379 -2.2824453735e+02, /* 0xc3643e9a */
380 -2.1921012878e+02, /* 0xc35b35cb */
382 #ifdef __STDC__
383 static const float qs3[6] = {
384 #else
385 static float qs3[6] = {
386 #endif
387 4.7665153503e+01, /* 0x423ea91e */
388 6.7386511230e+02, /* 0x4428775e */
389 3.3801528320e+03, /* 0x45534272 */
390 5.5477290039e+03, /* 0x45ad5dd5 */
391 1.9031191406e+03, /* 0x44ede3d0 */
392 -1.3520118713e+02, /* 0xc3073381 */
395 #ifdef __STDC__
396 static const float qr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
397 #else
398 static float qr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
399 #endif
400 -1.7838172539e-07, /* 0xb43f8932 */
401 -1.0251704603e-01, /* 0xbdd1f475 */
402 -2.7522056103e+00, /* 0xc0302423 */
403 -1.9663616180e+01, /* 0xc19d4f16 */
404 -4.2325313568e+01, /* 0xc2294d1f */
405 -2.1371921539e+01, /* 0xc1aaf9b2 */
407 #ifdef __STDC__
408 static const float qs2[6] = {
409 #else
410 static float qs2[6] = {
411 #endif
412 2.9533363342e+01, /* 0x41ec4454 */
413 2.5298155212e+02, /* 0x437cfb47 */
414 7.5750280762e+02, /* 0x443d602e */
415 7.3939318848e+02, /* 0x4438d92a */
416 1.5594900513e+02, /* 0x431bf2f2 */
417 -4.9594988823e+00, /* 0xc09eb437 */
420 #ifdef __STDC__
421 static float qonef(float x)
422 #else
423 static float qonef(x)
424 float x;
425 #endif
427 #ifdef __STDC__
428 const float *p,*q;
429 #else
430 float *p,*q;
431 #endif
432 float s,r,z;
433 int32_t ix;
434 GET_FLOAT_WORD(ix,x);
435 ix &= 0x7fffffff;
436 if(ix>=0x40200000) {p = qr8; q= qs8;}
437 else if(ix>=0x40f71c58){p = qr5; q= qs5;}
438 else if(ix>=0x4036db68){p = qr3; q= qs3;}
439 else if(ix>=0x40000000){p = qr2; q= qs2;}
440 z = one/(x*x);
441 r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
442 s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
443 return ((float).375 + r/s)/x;