12116Sjkh/* e_coshf.c -- float version of e_cosh.c. 22116Sjkh * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 32116Sjkh */ 42116Sjkh 52116Sjkh/* 62116Sjkh * ==================================================== 72116Sjkh * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 82116Sjkh * 92116Sjkh * Developed at SunPro, a Sun Microsystems, Inc. business. 102116Sjkh * Permission to use, copy, modify, and distribute this 118870Srgrimes * software is freely granted, provided that this notice 122116Sjkh * is preserved. 132116Sjkh * ==================================================== 142116Sjkh */ 152116Sjkh 16176451Sdas#include <sys/cdefs.h> 17176451Sdas__FBSDID("$FreeBSD: releng/10.2/lib/msun/src/e_coshf.c 226598 2011-10-21 06:28:47Z das $"); 182116Sjkh 192116Sjkh#include "math.h" 202116Sjkh#include "math_private.h" 212116Sjkh 222116Sjkhstatic const float one = 1.0, half=0.5, huge = 1.0e30; 232116Sjkh 2497407Salfredfloat 2597407Salfred__ieee754_coshf(float x) 268870Srgrimes{ 272116Sjkh float t,w; 282116Sjkh int32_t ix; 292116Sjkh 302116Sjkh GET_FLOAT_WORD(ix,x); 312116Sjkh ix &= 0x7fffffff; 322116Sjkh 332116Sjkh /* x is INF or NaN */ 348870Srgrimes if(ix>=0x7f800000) return x*x; 352116Sjkh 362116Sjkh /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */ 372116Sjkh if(ix<0x3eb17218) { 382116Sjkh t = expm1f(fabsf(x)); 392116Sjkh w = one+t; 40152352Sbde if (ix<0x39800000) return one; /* cosh(tiny) = 1 */ 412116Sjkh return one+(t*t)/(w+w); 422116Sjkh } 432116Sjkh 44152352Sbde /* |x| in [0.5*ln2,9], return (exp(|x|)+1/exp(|x|))/2; */ 45152352Sbde if (ix < 0x41100000) { 462116Sjkh t = __ieee754_expf(fabsf(x)); 472116Sjkh return half*t+half/t; 482116Sjkh } 492116Sjkh 50152352Sbde /* |x| in [9, log(maxfloat)] return half*exp(|x|) */ 51152352Sbde if (ix < 0x42b17217) return half*__ieee754_expf(fabsf(x)); 522116Sjkh 53152352Sbde /* |x| in [log(maxfloat), overflowthresold] */ 54226598Sdas if (ix<=0x42b2d4fc) 55226598Sdas return __ldexp_expf(fabsf(x), -1); 562116Sjkh 572116Sjkh /* |x| > overflowthresold, cosh(x) overflow */ 582116Sjkh return huge*huge; 592116Sjkh} 60