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/* origin: FreeBSD /usr/src/lib/msun/src/e_acosl.c */
/*
* ====================================================
* 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 acos.c.
* Converted to long double by David Schultz <das@FreeBSD.ORG>.
*/
#include "libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double acosl(long double x)
{
return acos(x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
#include "__invtrigl.h"
#if LDBL_MANT_DIG == 64
#define CLEARBOTTOM(u) (u.i.m &= -1ULL << 32)
#elif LDBL_MANT_DIG == 113
#define CLEARBOTTOM(u) (u.i.lo = 0)
#endif
long double acosl(long double x)
{
union ldshape u = {x};
long double z, s, c, f;
uint16_t e = u.i.se & 0x7fff;
/* |x| >= 1 or nan */
if (e >= 0x3fff) {
if (x == 1)
return 0;
if (x == -1)
return 2*pio2_hi + 0x1p-120f;
return 0/(x-x);
}
/* |x| < 0.5 */
if (e < 0x3fff - 1) {
if (e < 0x3fff - LDBL_MANT_DIG - 1)
return pio2_hi + 0x1p-120f;
return pio2_hi - (__invtrigl_R(x*x)*x - pio2_lo + x);
}
/* x < -0.5 */
if (u.i.se >> 15) {
z = (1 + x)*0.5;
s = sqrtl(z);
return 2*(pio2_hi - (__invtrigl_R(z)*s - pio2_lo + s));
}
/* x > 0.5 */
z = (1 - x)*0.5;
s = sqrtl(z);
u.f = s;
CLEARBOTTOM(u);
f = u.f;
c = (z - f*f)/(s + f);
return 2*(__invtrigl_R(z)*s + c + f);
}
#endif
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