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Diffstat (limited to 'lib/libm/src/e_acosl.c')
| -rw-r--r-- | lib/libm/src/e_acosl.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/lib/libm/src/e_acosl.c b/lib/libm/src/e_acosl.c new file mode 100644 index 00000000000..7e00b504dc5 --- /dev/null +++ b/lib/libm/src/e_acosl.c @@ -0,0 +1,104 @@ +/* $OpenBSD: e_acosl.c,v 1.1 2008/12/09 20:00:35 martynas Exp $ */ +/* @(#)e_acos.c 1.3 95/01/18 */ +/* FreeBSD: head/lib/msun/src/e_acos.c 176451 2008-02-22 02:30:36Z das */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunSoft, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +/* + * See comments in e_acos.c. + * Converted to long double by David Schultz <das@FreeBSD.ORG>. + * Adapted for OpenBSD by Martynas Venckus <martynas@openbsd.org>. + */ + +#include <float.h> +#include <math.h> + +#include "invtrig.h" +#include "math_private.h" + +#ifdef EXT_IMPLICIT_NBIT +#define LDBL_NBIT 0 +#else /* EXT_IMPLICIT_NBIT */ +#define LDBL_NBIT 0x80000000 +#endif /* EXT_IMPLICIT_NBIT */ + +static const long double +one= 1.00000000000000000000e+00; + +#if defined(__amd64__) || defined(__i386__) +/* XXX Work around the fact that gcc truncates long double constants on i386 */ +static volatile double +pi1 = 3.14159265358979311600e+00, /* 0x1.921fb54442d18p+1 */ +pi2 = 1.22514845490862001043e-16; /* 0x1.1a80000000000p-53 */ +#define pi ((long double)pi1 + pi2) +#else +static const long double +pi = 3.14159265358979323846264338327950280e+00L; +#endif + +long double +acosl(long double x) +{ + union { + long double e; + struct ieee_ext bits; + } u; + long double z,p,q,r,w,s,c,df; + int16_t expsign, expt; + u.e = x; + expsign = (u.bits.ext_sign << 15) | u.bits.ext_exp; + expt = expsign & 0x7fff; + if(expt >= BIAS) { /* |x| >= 1 */ + if(expt==BIAS && ((u.bits.ext_frach&~LDBL_NBIT) +#ifdef EXT_FRACHMBITS + | u.bits.ext_frachm +#endif /* EXT_FRACHMBITS */ +#ifdef EXT_FRACLMBITS + | u.bits.ext_fraclm +#endif /* EXT_FRACLMBITS */ + | u.bits.ext_fracl)==0) { + if (expsign>0) return 0.0; /* acos(1) = 0 */ + else return pi+2.0*pio2_lo; /* acos(-1)= pi */ + } + return (x-x)/(x-x); /* acos(|x|>1) is NaN */ + } + if(expt<BIAS-1) { /* |x| < 0.5 */ + if(expt<ACOS_CONST) return pio2_hi+pio2_lo;/*x tiny: acosl=pi/2*/ + z = x*x; + p = P(z); + q = Q(z); + r = p/q; + return pio2_hi - (x - (pio2_lo-x*r)); + } else if (expsign<0) { /* x < -0.5 */ + z = (one+x)*0.5; + p = P(z); + q = Q(z); + s = sqrtl(z); + r = p/q; + w = r*s-pio2_lo; + return pi - 2.0*(s+w); + } else { /* x > 0.5 */ + z = (one-x)*0.5; + s = sqrtl(z); + u.e = s; + u.bits.ext_fracl = 0; +#ifdef EXT_FRACLMBITS + u.bits.ext_fraclm = 0; +#endif /* EXT_FRACLMBITS */ + df = u.e; + c = (z-df*df)/(s+df); + p = P(z); + q = Q(z); + r = p/q; + w = r*s+c; + return 2.0*(df+w); + } +} |