1 /* origin: FreeBSD /usr/src/lib/msun/src/e_asinl.c */
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 * Developed at SunSoft, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
10 * ====================================================
13 * See comments in asin.c.
14 * Converted to long double by David Schultz <das@FreeBSD.ORG>.
19 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
20 long double asinl(long double x)
24 #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
25 #include "__invtrigl.h"
26 static const long double huge = 1.000e+300;
27 static const long double pio4_hi = 7.85398163397448309628e-01L;
28 #define ASIN_LINEAR (BIAS - 32) /* 2**-32 */
30 #define THRESH ((0xe666666666666666ULL>>(64-(MANH_SIZE-1)))|LDBL_NBIT)
32 long double asinl(long double x)
35 long double t=0.0,w,p,q,c,r,s;
36 int16_t expsign, expt;
39 expsign = u.xbits.expsign;
40 expt = expsign & 0x7fff;
41 if (expt >= BIAS) { /* |x|>= 1 */
43 ((u.bits.manh&~LDBL_NBIT)|u.bits.manl) == 0)
44 /* asin(1)=+-pi/2 with inexact */
45 return x*pio2_hi + x*pio2_lo;
46 return (x-x)/(x-x); /* asin(|x|>1) is NaN */
47 } else if (expt < BIAS-1) { /* |x|<0.5 */
48 if (expt < ASIN_LINEAR) { /* if |x| is small, asinl(x)=x */
49 /* return x with inexact if x!=0 */
65 if (u.bits.manh >= THRESH) { /* if |x| is close to 1 */
67 t = pio2_hi-(2.0*(s+s*w)-pio2_lo);
74 p = 2.0*s*r-(pio2_lo-2.0*c);