1/* e_j1f.c -- float version of e_j1.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
4
5/*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
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 * ====================================================
14 */
15
16#include <errno.h>
17#include <float.h>
18#include <math.h>
19#include <math_private.h>
20
21static float ponef(float), qonef(float);
22
23static const float
24huge = 1e30,
25one = 1.0,
26invsqrtpi= 5.6418961287e-01, /* 0x3f106ebb */
27tpi = 6.3661974669e-01, /* 0x3f22f983 */
28 /* R0/S0 on [0,2] */
29r00 = -6.2500000000e-02, /* 0xbd800000 */
30r01 = 1.4070566976e-03, /* 0x3ab86cfd */
31r02 = -1.5995563444e-05, /* 0xb7862e36 */
32r03 = 4.9672799207e-08, /* 0x335557d2 */
33s01 = 1.9153760746e-02, /* 0x3c9ce859 */
34s02 = 1.8594678841e-04, /* 0x3942fab6 */
35s03 = 1.1771846857e-06, /* 0x359dffc2 */
36s04 = 5.0463624390e-09, /* 0x31ad6446 */
37s05 = 1.2354227016e-11; /* 0x2d59567e */
38
39static const float zero = 0.0;
40
41float
42__ieee754_j1f(float x)
43{
44 float z, s,c,ss,cc,r,u,v,y;
45 int32_t hx,ix;
46
47 GET_FLOAT_WORD(hx,x);
48 ix = hx&0x7fffffff;
49 if(__builtin_expect(ix>=0x7f800000, 0)) return one/x;
50 y = fabsf(x);
51 if(ix >= 0x40000000) { /* |x| >= 2.0 */
52 __sincosf (y, &s, &c);
53 ss = -s-c;
54 cc = s-c;
55 if(ix<0x7f000000) { /* make sure y+y not overflow */
56 z = __cosf(y+y);
57 if ((s*c)>zero) cc = z/ss;
58 else ss = z/cc;
59 }
60 /*
61 * j1(x) = 1/sqrt(pi) * (P(1,x)*cc - Q(1,x)*ss) / sqrt(x)
62 * y1(x) = 1/sqrt(pi) * (P(1,x)*ss + Q(1,x)*cc) / sqrt(x)
63 */
64 if(ix>0x48000000) z = (invsqrtpi*cc)/__ieee754_sqrtf(y);
65 else {
66 u = ponef(y); v = qonef(y);
67 z = invsqrtpi*(u*cc-v*ss)/__ieee754_sqrtf(y);
68 }
69 if(hx<0) return -z;
70 else return z;
71 }
72 if(__builtin_expect(ix<0x32000000, 0)) { /* |x|<2**-27 */
73 if(huge+x>one) { /* inexact if x!=0 necessary */
74 float ret = math_narrow_eval ((float) 0.5 * x);
75 math_check_force_underflow (ret);
76 if (ret == 0 && x != 0)
77 __set_errno (ERANGE);
78 return ret;
79 }
80 }
81 z = x*x;
82 r = z*(r00+z*(r01+z*(r02+z*r03)));
83 s = one+z*(s01+z*(s02+z*(s03+z*(s04+z*s05))));
84 r *= x;
85 return(x*(float)0.5+r/s);
86}
87strong_alias (__ieee754_j1f, __j1f_finite)
88
89static const float U0[5] = {
90 -1.9605709612e-01, /* 0xbe48c331 */
91 5.0443872809e-02, /* 0x3d4e9e3c */
92 -1.9125689287e-03, /* 0xbafaaf2a */
93 2.3525259166e-05, /* 0x37c5581c */
94 -9.1909917899e-08, /* 0xb3c56003 */
95};
96static const float V0[5] = {
97 1.9916731864e-02, /* 0x3ca3286a */
98 2.0255257550e-04, /* 0x3954644b */
99 1.3560879779e-06, /* 0x35b602d4 */
100 6.2274145840e-09, /* 0x31d5f8eb */
101 1.6655924903e-11, /* 0x2d9281cf */
102};
103
104float
105__ieee754_y1f(float x)
106{
107 float z, s,c,ss,cc,u,v;
108 int32_t hx,ix;
109
110 GET_FLOAT_WORD(hx,x);
111 ix = 0x7fffffff&hx;
112 /* if Y1(NaN) is NaN, Y1(-inf) is NaN, Y1(inf) is 0 */
113 if(__builtin_expect(ix>=0x7f800000, 0)) return one/(x+x*x);
114 if(__builtin_expect(ix==0, 0))
115 return -1/zero; /* -inf and divide by zero exception. */
116 if(__builtin_expect(hx<0, 0)) return zero/(zero*x);
117 if(ix >= 0x40000000) { /* |x| >= 2.0 */
118 SET_RESTORE_ROUNDF (FE_TONEAREST);
119 __sincosf (x, &s, &c);
120 ss = -s-c;
121 cc = s-c;
122 if(ix<0x7f000000) { /* make sure x+x not overflow */
123 z = __cosf(x+x);
124 if ((s*c)>zero) cc = z/ss;
125 else ss = z/cc;
126 }
127 /* y1(x) = sqrt(2/(pi*x))*(p1(x)*sin(x0)+q1(x)*cos(x0))
128 * where x0 = x-3pi/4
129 * Better formula:
130 * cos(x0) = cos(x)cos(3pi/4)+sin(x)sin(3pi/4)
131 * = 1/sqrt(2) * (sin(x) - cos(x))
132 * sin(x0) = sin(x)cos(3pi/4)-cos(x)sin(3pi/4)
133 * = -1/sqrt(2) * (cos(x) + sin(x))
134 * To avoid cancellation, use
135 * sin(x) +- cos(x) = -cos(2x)/(sin(x) -+ cos(x))
136 * to compute the worse one.
137 */
138 if(ix>0x48000000) z = (invsqrtpi*ss)/__ieee754_sqrtf(x);
139 else {
140 u = ponef(x); v = qonef(x);
141 z = invsqrtpi*(u*ss+v*cc)/__ieee754_sqrtf(x);
142 }
143 return z;
144 }
145 if(__builtin_expect(ix<=0x33000000, 0)) { /* x < 2**-25 */
146 z = -tpi / x;
147 if (isinf (z))
148 __set_errno (ERANGE);
149 return z;
150 }
151 z = x*x;
152 u = U0[0]+z*(U0[1]+z*(U0[2]+z*(U0[3]+z*U0[4])));
153 v = one+z*(V0[0]+z*(V0[1]+z*(V0[2]+z*(V0[3]+z*V0[4]))));
154 return(x*(u/v) + tpi*(__ieee754_j1f(x)*__ieee754_logf(x)-one/x));
155}
156strong_alias (__ieee754_y1f, __y1f_finite)
157
158/* For x >= 8, the asymptotic expansions of pone is
159 * 1 + 15/128 s^2 - 4725/2^15 s^4 - ..., where s = 1/x.
160 * We approximate pone by
161 * pone(x) = 1 + (R/S)
162 * where R = pr0 + pr1*s^2 + pr2*s^4 + ... + pr5*s^10
163 * S = 1 + ps0*s^2 + ... + ps4*s^10
164 * and
165 * | pone(x)-1-R/S | <= 2 ** ( -60.06)
166 */
167
168static const float pr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
169 0.0000000000e+00, /* 0x00000000 */
170 1.1718750000e-01, /* 0x3df00000 */
171 1.3239480972e+01, /* 0x4153d4ea */
172 4.1205184937e+02, /* 0x43ce06a3 */
173 3.8747453613e+03, /* 0x45722bed */
174 7.9144794922e+03, /* 0x45f753d6 */
175};
176static const float ps8[5] = {
177 1.1420736694e+02, /* 0x42e46a2c */
178 3.6509309082e+03, /* 0x45642ee5 */
179 3.6956207031e+04, /* 0x47105c35 */
180 9.7602796875e+04, /* 0x47bea166 */
181 3.0804271484e+04, /* 0x46f0a88b */
182};
183
184static const float pr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
185 1.3199052094e-11, /* 0x2d68333f */
186 1.1718749255e-01, /* 0x3defffff */
187 6.8027510643e+00, /* 0x40d9b023 */
188 1.0830818176e+02, /* 0x42d89dca */
189 5.1763616943e+02, /* 0x440168b7 */
190 5.2871520996e+02, /* 0x44042dc6 */
191};
192static const float ps5[5] = {
193 5.9280597687e+01, /* 0x426d1f55 */
194 9.9140142822e+02, /* 0x4477d9b1 */
195 5.3532670898e+03, /* 0x45a74a23 */
196 7.8446904297e+03, /* 0x45f52586 */
197 1.5040468750e+03, /* 0x44bc0180 */
198};
199
200static const float pr3[6] = {
201 3.0250391081e-09, /* 0x314fe10d */
202 1.1718686670e-01, /* 0x3defffab */
203 3.9329774380e+00, /* 0x407bb5e7 */
204 3.5119403839e+01, /* 0x420c7a45 */
205 9.1055007935e+01, /* 0x42b61c2a */
206 4.8559066772e+01, /* 0x42423c7c */
207};
208static const float ps3[5] = {
209 3.4791309357e+01, /* 0x420b2a4d */
210 3.3676245117e+02, /* 0x43a86198 */
211 1.0468714600e+03, /* 0x4482dbe3 */
212 8.9081134033e+02, /* 0x445eb3ed */
213 1.0378793335e+02, /* 0x42cf936c */
214};
215
216static const float pr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
217 1.0771083225e-07, /* 0x33e74ea8 */
218 1.1717621982e-01, /* 0x3deffa16 */
219 2.3685150146e+00, /* 0x401795c0 */
220 1.2242610931e+01, /* 0x4143e1bc */
221 1.7693971634e+01, /* 0x418d8d41 */
222 5.0735230446e+00, /* 0x40a25a4d */
223};
224static const float ps2[5] = {
225 2.1436485291e+01, /* 0x41ab7dec */
226 1.2529022980e+02, /* 0x42fa9499 */
227 2.3227647400e+02, /* 0x436846c7 */
228 1.1767937469e+02, /* 0x42eb5bd7 */
229 8.3646392822e+00, /* 0x4105d590 */
230};
231
232static float
233ponef(float x)
234{
235 const float *p,*q;
236 float z,r,s;
237 int32_t ix;
238 GET_FLOAT_WORD(ix,x);
239 ix &= 0x7fffffff;
240 /* ix >= 0x40000000 for all calls to this function. */
241 if(ix>=0x41000000) {p = pr8; q= ps8;}
242 else if(ix>=0x40f71c58){p = pr5; q= ps5;}
243 else if(ix>=0x4036db68){p = pr3; q= ps3;}
244 else {p = pr2; q= ps2;}
245 z = one/(x*x);
246 r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
247 s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*q[4]))));
248 return one+ r/s;
249}
250
251
252/* For x >= 8, the asymptotic expansions of qone is
253 * 3/8 s - 105/1024 s^3 - ..., where s = 1/x.
254 * We approximate pone by
255 * qone(x) = s*(0.375 + (R/S))
256 * where R = qr1*s^2 + qr2*s^4 + ... + qr5*s^10
257 * S = 1 + qs1*s^2 + ... + qs6*s^12
258 * and
259 * | qone(x)/s -0.375-R/S | <= 2 ** ( -61.13)
260 */
261
262static const float qr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */
263 0.0000000000e+00, /* 0x00000000 */
264 -1.0253906250e-01, /* 0xbdd20000 */
265 -1.6271753311e+01, /* 0xc1822c8d */
266 -7.5960174561e+02, /* 0xc43de683 */
267 -1.1849806641e+04, /* 0xc639273a */
268 -4.8438511719e+04, /* 0xc73d3683 */
269};
270static const float qs8[6] = {
271 1.6139537048e+02, /* 0x43216537 */
272 7.8253862305e+03, /* 0x45f48b17 */
273 1.3387534375e+05, /* 0x4802bcd6 */
274 7.1965775000e+05, /* 0x492fb29c */
275 6.6660125000e+05, /* 0x4922be94 */
276 -2.9449025000e+05, /* 0xc88fcb48 */
277};
278
279static const float qr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */
280 -2.0897993405e-11, /* 0xadb7d219 */
281 -1.0253904760e-01, /* 0xbdd1fffe */
282 -8.0564479828e+00, /* 0xc100e736 */
283 -1.8366960144e+02, /* 0xc337ab6b */
284 -1.3731937256e+03, /* 0xc4aba633 */
285 -2.6124443359e+03, /* 0xc523471c */
286};
287static const float qs5[6] = {
288 8.1276550293e+01, /* 0x42a28d98 */
289 1.9917987061e+03, /* 0x44f8f98f */
290 1.7468484375e+04, /* 0x468878f8 */
291 4.9851425781e+04, /* 0x4742bb6d */
292 2.7948074219e+04, /* 0x46da5826 */
293 -4.7191835938e+03, /* 0xc5937978 */
294};
295
296static const float qr3[6] = {
297 -5.0783124372e-09, /* 0xb1ae7d4f */
298 -1.0253783315e-01, /* 0xbdd1ff5b */
299 -4.6101160049e+00, /* 0xc0938612 */
300 -5.7847221375e+01, /* 0xc267638e */
301 -2.2824453735e+02, /* 0xc3643e9a */
302 -2.1921012878e+02, /* 0xc35b35cb */
303};
304static const float qs3[6] = {
305 4.7665153503e+01, /* 0x423ea91e */
306 6.7386511230e+02, /* 0x4428775e */
307 3.3801528320e+03, /* 0x45534272 */
308 5.5477290039e+03, /* 0x45ad5dd5 */
309 1.9031191406e+03, /* 0x44ede3d0 */
310 -1.3520118713e+02, /* 0xc3073381 */
311};
312
313static const float qr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */
314 -1.7838172539e-07, /* 0xb43f8932 */
315 -1.0251704603e-01, /* 0xbdd1f475 */
316 -2.7522056103e+00, /* 0xc0302423 */
317 -1.9663616180e+01, /* 0xc19d4f16 */
318 -4.2325313568e+01, /* 0xc2294d1f */
319 -2.1371921539e+01, /* 0xc1aaf9b2 */
320};
321static const float qs2[6] = {
322 2.9533363342e+01, /* 0x41ec4454 */
323 2.5298155212e+02, /* 0x437cfb47 */
324 7.5750280762e+02, /* 0x443d602e */
325 7.3939318848e+02, /* 0x4438d92a */
326 1.5594900513e+02, /* 0x431bf2f2 */
327 -4.9594988823e+00, /* 0xc09eb437 */
328};
329
330static float
331qonef(float x)
332{
333 const float *p,*q;
334 float s,r,z;
335 int32_t ix;
336 GET_FLOAT_WORD(ix,x);
337 ix &= 0x7fffffff;
338 /* ix >= 0x40000000 for all calls to this function. */
339 if(ix>=0x40200000) {p = qr8; q= qs8;}
340 else if(ix>=0x40f71c58){p = qr5; q= qs5;}
341 else if(ix>=0x4036db68){p = qr3; q= qs3;}
342 else {p = qr2; q= qs2;}
343 z = one/(x*x);
344 r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
345 s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
346 return ((float).375 + r/s)/x;
347}
348