diff options
Diffstat (limited to 'libm/src/e_acoshf.c')
| -rw-r--r-- | libm/src/e_acoshf.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/libm/src/e_acoshf.c b/libm/src/e_acoshf.c new file mode 100644 index 0000000..5257914 --- /dev/null +++ b/libm/src/e_acoshf.c @@ -0,0 +1,49 @@ +/* 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. + * ==================================================== + */ + +#ifndef lint +static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_acoshf.c,v 1.7 2002/05/28 17:03:12 alfred Exp $"; +#endif + +#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)); + } +} |