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/* origin: FreeBSD /usr/src/lib/msun/src/e_asinl.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 asin.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 asinl(long double x)
{
return asin(x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
#include "__invtrigl.h"
/* 0.95 */
#define THRESH ((0xe666666666666666ULL>>(64-(LDBL_MANH_SIZE-1)))|LDBL_NBIT)
long double asinl(long double x)
{
union IEEEl2bits u;
long double z,r,s;
uint16_t expsign, expt;
u.e = x;
expsign = u.xbits.expsign;
expt = expsign & 0x7fff;
if (expt >= 0x3fff) { /* |x| >= 1 or nan */
if (expt == 0x3fff &&
((u.bits.manh&~LDBL_NBIT)|u.bits.manl) == 0)
/* asin(+-1)=+-pi/2 with inexact */
return x*pio2_hi + 0x1p-120f;
return 0/(x-x);
}
if (expt < 0x3fff - 1) { /* |x| < 0.5 */
if (expt < 0x3fff - 32) { /* |x|<0x1p-32, asinl(x)=x */
/* return x with inexact if x!=0 */
FORCE_EVAL(x + 0x1p120f);
return x;
}
return x + x*__invtrigl_R(x*x);
}
/* 1 > |x| >= 0.5 */
z = (1.0 - fabsl(x))*0.5;
s = sqrtl(z);
r = __invtrigl_R(z);
if (u.bits.manh >= THRESH) { /* if |x| is close to 1 */
x = pio2_hi - (2*(s+s*r)-pio2_lo);
} else {
long double f, c;
u.e = s;
u.bits.manl = 0;
f = u.e;
c = (z-f*f)/(s+f);
x = 0.5*pio2_hi-(2*s*r - (pio2_lo-2*c) - (0.5*pio2_hi-2*f));
}
if (expsign>>15)
return -x;
return x;
}
#endif
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