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Diffstat (limited to 'newlib/libm/math/ef_acosh.c')
| -rw-r--r-- | newlib/libm/math/ef_acosh.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/newlib/libm/math/ef_acosh.c b/newlib/libm/math/ef_acosh.c new file mode 100644 index 00000000000..37c788576ef --- /dev/null +++ b/newlib/libm/math/ef_acosh.c @@ -0,0 +1,53 @@ +/* ef_acosh.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 "fdlibm.h" + +#ifdef __STDC__ +static const float +#else +static float +#endif +one = 1.0, +ln2 = 6.9314718246e-01; /* 0x3f317218 */ + +#ifdef __STDC__ + float __ieee754_acoshf(float x) +#else + float __ieee754_acoshf(x) + float x; +#endif +{ + 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)); + } +} |