mirror of https://git.musl-libc.org/git/musl
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
64 lines
1.5 KiB
64 lines
1.5 KiB
/* origin: FreeBSD /usr/src/lib/msun/src/e_asinf.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 "libm.h"
|
|
|
|
static const float
|
|
one = 1.0000000000e+00, /* 0x3F800000 */
|
|
huge = 1.000e+30,
|
|
/* coefficients for R(x^2) */
|
|
pS0 = 1.6666586697e-01,
|
|
pS1 = -4.2743422091e-02,
|
|
pS2 = -8.6563630030e-03,
|
|
qS1 = -7.0662963390e-01;
|
|
|
|
static const double
|
|
pio2 = 1.570796326794896558e+00;
|
|
|
|
float asinf(float x)
|
|
{
|
|
double s;
|
|
float t,w,p,q;
|
|
int32_t hx,ix;
|
|
|
|
GET_FLOAT_WORD(hx, x);
|
|
ix = hx & 0x7fffffff;
|
|
if (ix >= 0x3f800000) { /* |x| >= 1 */
|
|
if (ix == 0x3f800000) /* |x| == 1 */
|
|
return x*pio2; /* asin(+-1) = +-pi/2 with inexact */
|
|
return (x-x)/(x-x); /* asin(|x|>1) is NaN */
|
|
} else if (ix < 0x3f000000) { /* |x|<0.5 */
|
|
if (ix < 0x39800000) { /* |x| < 2**-12 */
|
|
if (huge+x > one)
|
|
return x; /* return x with inexact if x!=0 */
|
|
}
|
|
t = x*x;
|
|
p = t*(pS0+t*(pS1+t*pS2));
|
|
q = one+t*qS1;
|
|
w = p/q;
|
|
return x + x*w;
|
|
}
|
|
/* 1 > |x| >= 0.5 */
|
|
w = one - fabsf(x);
|
|
t = w*0.5f;
|
|
p = t*(pS0+t*(pS1+t*pS2));
|
|
q = one+t*qS1;
|
|
s = sqrt(t);
|
|
w = p/q;
|
|
t = pio2-2.0*(s+s*w);
|
|
if (hx > 0)
|
|
return t;
|
|
return -t;
|
|
}
|
|
|