/* e_j1f.c -- float version of e_j1.c. * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice * is preserved. * ==================================================== */ #include __FBSDID("$FreeBSD: head/lib/msun/src/e_j1f.c 336089 2018-07-08 16:26:13Z markj $"); /* * See e_j1.c for complete comments. */ #include "math.h" #include "math_private.h" static __inline float ponef(float), qonef(float); static const volatile float vone = 1, vzero = 0; static const float huge = 1e30, one = 1.0, invsqrtpi= 5.6418961287e-01, /* 0x3f106ebb */ tpi = 6.3661974669e-01, /* 0x3f22f983 */ /* R0/S0 on [0,2] */ r00 = -6.2500000000e-02, /* 0xbd800000 */ r01 = 1.4070566976e-03, /* 0x3ab86cfd */ r02 = -1.5995563444e-05, /* 0xb7862e36 */ r03 = 4.9672799207e-08, /* 0x335557d2 */ s01 = 1.9153760746e-02, /* 0x3c9ce859 */ s02 = 1.8594678841e-04, /* 0x3942fab6 */ s03 = 1.1771846857e-06, /* 0x359dffc2 */ s04 = 5.0463624390e-09, /* 0x31ad6446 */ s05 = 1.2354227016e-11; /* 0x2d59567e */ static const float zero = 0.0; float __ieee754_j1f(float x) { float z, s,c,ss,cc,r,u,v,y; int32_t hx,ix; GET_FLOAT_WORD(hx,x); ix = hx&0x7fffffff; if(ix>=0x7f800000) return one/x; y = fabsf(x); if(ix >= 0x40000000) { /* |x| >= 2.0 */ s = sinf(y); c = cosf(y); ss = -s-c; cc = s-c; if(ix<0x7f000000) { /* make sure y+y not overflow */ z = cosf(y+y); if ((s*c)>zero) cc = z/ss; else ss = z/cc; } /* * j1(x) = 1/sqrt(pi) * (P(1,x)*cc - Q(1,x)*ss) / sqrt(x) * y1(x) = 1/sqrt(pi) * (P(1,x)*ss + Q(1,x)*cc) / sqrt(x) */ if(ix>0x58000000) z = (invsqrtpi*cc)/sqrtf(y); /* |x|>2**49 */ else { u = ponef(y); v = qonef(y); z = invsqrtpi*(u*cc-v*ss)/sqrtf(y); } if(hx<0) return -z; else return z; } if(ix<0x39000000) { /* |x|<2**-13 */ if(huge+x>one) return (float)0.5*x;/* inexact if x!=0 necessary */ } z = x*x; r = z*(r00+z*(r01+z*(r02+z*r03))); s = one+z*(s01+z*(s02+z*(s03+z*(s04+z*s05)))); r *= x; return(x*(float)0.5+r/s); } static const float U0[5] = { -1.9605709612e-01, /* 0xbe48c331 */ 5.0443872809e-02, /* 0x3d4e9e3c */ -1.9125689287e-03, /* 0xbafaaf2a */ 2.3525259166e-05, /* 0x37c5581c */ -9.1909917899e-08, /* 0xb3c56003 */ }; static const float V0[5] = { 1.9916731864e-02, /* 0x3ca3286a */ 2.0255257550e-04, /* 0x3954644b */ 1.3560879779e-06, /* 0x35b602d4 */ 6.2274145840e-09, /* 0x31d5f8eb */ 1.6655924903e-11, /* 0x2d9281cf */ }; float __ieee754_y1f(float x) { float z, s,c,ss,cc,u,v; int32_t hx,ix; GET_FLOAT_WORD(hx,x); ix = 0x7fffffff&hx; if(ix>=0x7f800000) return vone/(x+x*x); if(ix==0) return -one/vzero; if(hx<0) return vzero/vzero; if(ix >= 0x40000000) { /* |x| >= 2.0 */ s = sinf(x); c = cosf(x); ss = -s-c; cc = s-c; if(ix<0x7f000000) { /* make sure x+x not overflow */ z = cosf(x+x); if ((s*c)>zero) cc = z/ss; else ss = z/cc; } /* y1(x) = sqrt(2/(pi*x))*(p1(x)*sin(x0)+q1(x)*cos(x0)) * where x0 = x-3pi/4 * Better formula: * cos(x0) = cos(x)cos(3pi/4)+sin(x)sin(3pi/4) * = 1/sqrt(2) * (sin(x) - cos(x)) * sin(x0) = sin(x)cos(3pi/4)-cos(x)sin(3pi/4) * = -1/sqrt(2) * (cos(x) + sin(x)) * To avoid cancellation, use * sin(x) +- cos(x) = -cos(2x)/(sin(x) -+ cos(x)) * to compute the worse one. */ if(ix>0x58000000) z = (invsqrtpi*ss)/sqrtf(x); /* |x|>2**49 */ else { u = ponef(x); v = qonef(x); z = invsqrtpi*(u*ss+v*cc)/sqrtf(x); } return z; } if(ix<=0x33000000) { /* x < 2**-25 */ return(-tpi/x); } z = x*x; u = U0[0]+z*(U0[1]+z*(U0[2]+z*(U0[3]+z*U0[4]))); v = one+z*(V0[0]+z*(V0[1]+z*(V0[2]+z*(V0[3]+z*V0[4])))); return(x*(u/v) + tpi*(__ieee754_j1f(x)*__ieee754_logf(x)-one/x)); } /* For x >= 8, the asymptotic expansions of pone is * 1 + 15/128 s^2 - 4725/2^15 s^4 - ..., where s = 1/x. * We approximate pone by * pone(x) = 1 + (R/S) * where R = pr0 + pr1*s^2 + pr2*s^4 + ... + pr5*s^10 * S = 1 + ps0*s^2 + ... + ps4*s^10 * and * | pone(x)-1-R/S | <= 2 ** ( -60.06) */ static const float pr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */ 0.0000000000e+00, /* 0x00000000 */ 1.1718750000e-01, /* 0x3df00000 */ 1.3239480972e+01, /* 0x4153d4ea */ 4.1205184937e+02, /* 0x43ce06a3 */ 3.8747453613e+03, /* 0x45722bed */ 7.9144794922e+03, /* 0x45f753d6 */ }; static const float ps8[5] = { 1.1420736694e+02, /* 0x42e46a2c */ 3.6509309082e+03, /* 0x45642ee5 */ 3.6956207031e+04, /* 0x47105c35 */ 9.7602796875e+04, /* 0x47bea166 */ 3.0804271484e+04, /* 0x46f0a88b */ }; static const float pr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */ 1.3199052094e-11, /* 0x2d68333f */ 1.1718749255e-01, /* 0x3defffff */ 6.8027510643e+00, /* 0x40d9b023 */ 1.0830818176e+02, /* 0x42d89dca */ 5.1763616943e+02, /* 0x440168b7 */ 5.2871520996e+02, /* 0x44042dc6 */ }; static const float ps5[5] = { 5.9280597687e+01, /* 0x426d1f55 */ 9.9140142822e+02, /* 0x4477d9b1 */ 5.3532670898e+03, /* 0x45a74a23 */ 7.8446904297e+03, /* 0x45f52586 */ 1.5040468750e+03, /* 0x44bc0180 */ }; static const float pr3[6] = { 3.0250391081e-09, /* 0x314fe10d */ 1.1718686670e-01, /* 0x3defffab */ 3.9329774380e+00, /* 0x407bb5e7 */ 3.5119403839e+01, /* 0x420c7a45 */ 9.1055007935e+01, /* 0x42b61c2a */ 4.8559066772e+01, /* 0x42423c7c */ }; static const float ps3[5] = { 3.4791309357e+01, /* 0x420b2a4d */ 3.3676245117e+02, /* 0x43a86198 */ 1.0468714600e+03, /* 0x4482dbe3 */ 8.9081134033e+02, /* 0x445eb3ed */ 1.0378793335e+02, /* 0x42cf936c */ }; static const float pr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */ 1.0771083225e-07, /* 0x33e74ea8 */ 1.1717621982e-01, /* 0x3deffa16 */ 2.3685150146e+00, /* 0x401795c0 */ 1.2242610931e+01, /* 0x4143e1bc */ 1.7693971634e+01, /* 0x418d8d41 */ 5.0735230446e+00, /* 0x40a25a4d */ }; static const float ps2[5] = { 2.1436485291e+01, /* 0x41ab7dec */ 1.2529022980e+02, /* 0x42fa9499 */ 2.3227647400e+02, /* 0x436846c7 */ 1.1767937469e+02, /* 0x42eb5bd7 */ 8.3646392822e+00, /* 0x4105d590 */ }; static __inline float ponef(float x) { const float *p,*q; float z,r,s; int32_t ix; GET_FLOAT_WORD(ix,x); ix &= 0x7fffffff; if(ix>=0x41000000) {p = pr8; q= ps8;} else if(ix>=0x409173eb){p = pr5; q= ps5;} else if(ix>=0x4036d917){p = pr3; q= ps3;} else {p = pr2; q= ps2;} /* ix>=0x40000000 */ z = one/(x*x); r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5])))); s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*q[4])))); return one+ r/s; } /* For x >= 8, the asymptotic expansions of qone is * 3/8 s - 105/1024 s^3 - ..., where s = 1/x. * We approximate pone by * qone(x) = s*(0.375 + (R/S)) * where R = qr1*s^2 + qr2*s^4 + ... + qr5*s^10 * S = 1 + qs1*s^2 + ... + qs6*s^12 * and * | qone(x)/s -0.375-R/S | <= 2 ** ( -61.13) */ static const float qr8[6] = { /* for x in [inf, 8]=1/[0,0.125] */ 0.0000000000e+00, /* 0x00000000 */ -1.0253906250e-01, /* 0xbdd20000 */ -1.6271753311e+01, /* 0xc1822c8d */ -7.5960174561e+02, /* 0xc43de683 */ -1.1849806641e+04, /* 0xc639273a */ -4.8438511719e+04, /* 0xc73d3683 */ }; static const float qs8[6] = { 1.6139537048e+02, /* 0x43216537 */ 7.8253862305e+03, /* 0x45f48b17 */ 1.3387534375e+05, /* 0x4802bcd6 */ 7.1965775000e+05, /* 0x492fb29c */ 6.6660125000e+05, /* 0x4922be94 */ -2.9449025000e+05, /* 0xc88fcb48 */ }; static const float qr5[6] = { /* for x in [8,4.5454]=1/[0.125,0.22001] */ -2.0897993405e-11, /* 0xadb7d219 */ -1.0253904760e-01, /* 0xbdd1fffe */ -8.0564479828e+00, /* 0xc100e736 */ -1.8366960144e+02, /* 0xc337ab6b */ -1.3731937256e+03, /* 0xc4aba633 */ -2.6124443359e+03, /* 0xc523471c */ }; static const float qs5[6] = { 8.1276550293e+01, /* 0x42a28d98 */ 1.9917987061e+03, /* 0x44f8f98f */ 1.7468484375e+04, /* 0x468878f8 */ 4.9851425781e+04, /* 0x4742bb6d */ 2.7948074219e+04, /* 0x46da5826 */ -4.7191835938e+03, /* 0xc5937978 */ }; static const float qr3[6] = { -5.0783124372e-09, /* 0xb1ae7d4f */ -1.0253783315e-01, /* 0xbdd1ff5b */ -4.6101160049e+00, /* 0xc0938612 */ -5.7847221375e+01, /* 0xc267638e */ -2.2824453735e+02, /* 0xc3643e9a */ -2.1921012878e+02, /* 0xc35b35cb */ }; static const float qs3[6] = { 4.7665153503e+01, /* 0x423ea91e */ 6.7386511230e+02, /* 0x4428775e */ 3.3801528320e+03, /* 0x45534272 */ 5.5477290039e+03, /* 0x45ad5dd5 */ 1.9031191406e+03, /* 0x44ede3d0 */ -1.3520118713e+02, /* 0xc3073381 */ }; static const float qr2[6] = {/* for x in [2.8570,2]=1/[0.3499,0.5] */ -1.7838172539e-07, /* 0xb43f8932 */ -1.0251704603e-01, /* 0xbdd1f475 */ -2.7522056103e+00, /* 0xc0302423 */ -1.9663616180e+01, /* 0xc19d4f16 */ -4.2325313568e+01, /* 0xc2294d1f */ -2.1371921539e+01, /* 0xc1aaf9b2 */ }; static const float qs2[6] = { 2.9533363342e+01, /* 0x41ec4454 */ 2.5298155212e+02, /* 0x437cfb47 */ 7.5750280762e+02, /* 0x443d602e */ 7.3939318848e+02, /* 0x4438d92a */ 1.5594900513e+02, /* 0x431bf2f2 */ -4.9594988823e+00, /* 0xc09eb437 */ }; static __inline float qonef(float x) { const float *p,*q; float s,r,z; int32_t ix; GET_FLOAT_WORD(ix,x); ix &= 0x7fffffff; if(ix>=0x41000000) {p = qr8; q= qs8;} else if(ix>=0x409173eb){p = qr5; q= qs5;} else if(ix>=0x4036d917){p = qr3; q= qs3;} else {p = qr2; q= qs2;} /* ix>=0x40000000 */ z = one/(x*x); r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5])))); s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5]))))); return ((float).375 + r/s)/x; }