diff options
Diffstat (limited to 'lib/mlibc/options/ansi/musl-generic-math/asinf.c')
-rw-r--r-- | lib/mlibc/options/ansi/musl-generic-math/asinf.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/lib/mlibc/options/ansi/musl-generic-math/asinf.c b/lib/mlibc/options/ansi/musl-generic-math/asinf.c new file mode 100644 index 0000000..bcd304a --- /dev/null +++ b/lib/mlibc/options/ansi/musl-generic-math/asinf.c @@ -0,0 +1,61 @@ +/* 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 double +pio2 = 1.570796326794896558e+00; + +static const float +/* coefficients for R(x^2) */ +pS0 = 1.6666586697e-01, +pS1 = -4.2743422091e-02, +pS2 = -8.6563630030e-03, +qS1 = -7.0662963390e-01; + +static float R(float z) +{ + float_t p, q; + p = z*(pS0+z*(pS1+z*pS2)); + q = 1.0f+z*qS1; + return p/q; +} + +float asinf(float x) +{ + double s; + float z; + uint32_t hx,ix; + + GET_FLOAT_WORD(hx, x); + ix = hx & 0x7fffffff; + if (ix >= 0x3f800000) { /* |x| >= 1 */ + if (ix == 0x3f800000) /* |x| == 1 */ + return x*pio2 + 0x1p-120f; /* asin(+-1) = +-pi/2 with inexact */ + return 0/(x-x); /* asin(|x|>1) is NaN */ + } + if (ix < 0x3f000000) { /* |x| < 0.5 */ + /* if 0x1p-126 <= |x| < 0x1p-12, avoid raising underflow */ + if (ix < 0x39800000 && ix >= 0x00800000) + return x; + return x + x*R(x*x); + } + /* 1 > |x| >= 0.5 */ + z = (1 - fabsf(x))*0.5f; + s = sqrt(z); + x = pio2 - 2*(s+s*R(z)); + if (hx >> 31) + return -x; + return x; +} |