| /* e_coshf.c -- float version of e_cosh.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, half=0.5, huge = 1.0e30; |
| |
| float |
| __ieee754_coshf(float x) |
| { |
| float t,w; |
| int32_t ix; |
| |
| GET_FLOAT_WORD(ix,x); |
| ix &= 0x7fffffff; |
| |
| /* x is INF or NaN */ |
| if(ix>=0x7f800000) return x*x; |
| |
| /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */ |
| if(ix<0x3eb17218) { |
| t = expm1f(fabsf(x)); |
| w = one+t; |
| if (ix<0x39800000) return one; /* cosh(tiny) = 1 */ |
| return one+(t*t)/(w+w); |
| } |
| |
| /* |x| in [0.5*ln2,9], return (exp(|x|)+1/exp(|x|))/2; */ |
| if (ix < 0x41100000) { |
| t = __ieee754_expf(fabsf(x)); |
| return half*t+half/t; |
| } |
| |
| /* |x| in [9, log(maxfloat)] return half*exp(|x|) */ |
| if (ix < 0x42b17217) return half*__ieee754_expf(fabsf(x)); |
| |
| /* |x| in [log(maxfloat), overflowthresold] */ |
| if (ix<=0x42b2d4fc) |
| return __ldexp_expf(fabsf(x), -1); |
| |
| /* |x| > overflowthresold, cosh(x) overflow */ |
| return huge*huge; |
| } |
