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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [newlib/] [libm/] [math/] [ef_asin.c] - Rev 193
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/* ef_asin.c -- float version of e_asin.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 "fdlibm.h" #ifdef __STDC__ static const float #else static float #endif one = 1.0000000000e+00, /* 0x3F800000 */ huge = 1.000e+30, pio2_hi = 1.57079637050628662109375f, pio2_lo = -4.37113900018624283e-8f, pio4_hi = 0.785398185253143310546875f, /* coefficient for R(x^2) */ pS0 = 1.6666667163e-01, /* 0x3e2aaaab */ pS1 = -3.2556581497e-01, /* 0xbea6b090 */ pS2 = 2.0121252537e-01, /* 0x3e4e0aa8 */ pS3 = -4.0055535734e-02, /* 0xbd241146 */ pS4 = 7.9153501429e-04, /* 0x3a4f7f04 */ pS5 = 3.4793309169e-05, /* 0x3811ef08 */ qS1 = -2.4033949375e+00, /* 0xc019d139 */ qS2 = 2.0209457874e+00, /* 0x4001572d */ qS3 = -6.8828397989e-01, /* 0xbf303361 */ qS4 = 7.7038154006e-02; /* 0x3d9dc62e */ #ifdef __STDC__ float __ieee754_asinf(float x) #else float __ieee754_asinf(x) float x; #endif { float t,w,p,q,c,r,s; __int32_t hx,ix; GET_FLOAT_WORD(hx,x); ix = hx&0x7fffffff; if(ix==0x3f800000) { /* asin(1)=+-pi/2 with inexact */ return x*pio2_hi+x*pio2_lo; } else if(ix> 0x3f800000) { /* |x|>= 1 */ return (x-x)/(x-x); /* asin(|x|>1) is NaN */ } else if (ix<0x3f000000) { /* |x|<0.5 */ if(ix<0x32000000) { /* if |x| < 2**-27 */ if(huge+x>one) return x;/* return x with inexact if x!=0*/ } else { t = x*x; p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5))))); q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4))); w = p/q; return x+x*w; } } /* 1> |x|>= 0.5 */ w = one-fabsf(x); t = w*(float)0.5; p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5))))); q = one+t*(qS1+t*(qS2+t*(qS3+t*qS4))); s = __ieee754_sqrtf(t); if(ix>=0x3F79999A) { /* if |x| > 0.975 */ w = p/q; t = pio2_hi-((float)2.0*(s+s*w)-pio2_lo); } else { __int32_t iw; w = s; GET_FLOAT_WORD(iw,w); SET_FLOAT_WORD(w,iw&0xfffff000); c = (t-w*w)/(s+w); r = p/q; p = (float)2.0*s*r-(pio2_lo-(float)2.0*c); q = pio4_hi-(float)2.0*w; t = pio4_hi-(p-q); } if(hx>0) return t; else return -t; }
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