/* e_acoshf.c -- float version of e_acosh.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 <sys/cdefs.h> __FBSDID("$FreeBSD$"); #include "math.h" #include "math_private.h" static const float one = 1.0, ln2 = 6.9314718246e-01; /* 0x3f317218 */ float __ieee754_acoshf(float x) { float t; int32_t hx; GET_FLOAT_WORD(hx,x); if(hx<0x3f800000) { /* x < 1 */ return (x-x)/(x-x); } else if(hx >=0x4d800000) { /* x > 2**28 */ if(hx >=0x7f800000) { /* x is inf of NaN */ return x+x; } else return __ieee754_logf(x)+ln2; /* acosh(huge)=log(2x) */ } else if (hx==0x3f800000) { return 0.0; /* acosh(1) = 0 */ } else if (hx > 0x40000000) { /* 2**28 > x > 2 */ t=x*x; return __ieee754_logf((float)2.0*x-one/(x+__ieee754_sqrtf(t-one))); } else { /* 1<x<2 */ t = x-one; return log1pf(t+__ieee754_sqrtf((float)2.0*t+t*t)); } } |