0,0 → 1,71 |
/* ef_cosh.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 "fdlibm.h" |
|
#ifdef __v810__ |
#define const |
#endif |
|
#ifdef __STDC__ |
static const float one = 1.0, half=0.5, huge = 1.0e30; |
#else |
static float one = 1.0, half=0.5, huge = 1.0e30; |
#endif |
|
#ifdef __STDC__ |
float __ieee754_coshf(float x) |
#else |
float __ieee754_coshf(x) |
float x; |
#endif |
{ |
float t,w; |
__int32_t ix; |
|
GET_FLOAT_WORD(ix,x); |
ix &= 0x7fffffff; |
|
/* x is INF or NaN */ |
if(!FLT_UWORD_IS_FINITE(ix)) 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<0x24000000) return w; /* cosh(tiny) = 1 */ |
return one+(t*t)/(w+w); |
} |
|
/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */ |
if (ix < 0x41b00000) { |
t = __ieee754_expf(fabsf(x)); |
return half*t+half/t; |
} |
|
/* |x| in [22, log(maxdouble)] return half*exp(|x|) */ |
if (ix <= FLT_UWORD_LOG_MAX) |
return half*__ieee754_expf(fabsf(x)); |
|
/* |x| in [log(maxdouble), overflowthresold] */ |
if (ix <= FLT_UWORD_LOG_2MAX) { |
w = __ieee754_expf(half*fabsf(x)); |
t = half*w; |
return t*w; |
} |
|
/* |x| > overflowthresold, cosh(x) overflow */ |
return huge*huge; |
} |