kopia lustrzana https://github.com/micropython/micropython
131 wiersze
3.5 KiB
C
131 wiersze
3.5 KiB
C
/*****************************************************************************/
|
|
/*****************************************************************************/
|
|
// asinf from musl-0.9.15
|
|
/*****************************************************************************/
|
|
/*****************************************************************************/
|
|
|
|
/* 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"
|
|
|
|
// dpgeorge: pio2 was double in original implementation of asinf
|
|
static const float
|
|
pio2_hi = 1.5707962513e+00f, /* 0x3fc90fda */
|
|
pio2_lo = 7.5497894159e-08f; /* 0x33a22168 */
|
|
|
|
static const float
|
|
/* coefficients for R(x^2) */
|
|
pS0 = 1.6666586697e-01f,
|
|
pS1 = -4.2743422091e-02f,
|
|
pS2 = -8.6563630030e-03f,
|
|
qS1 = -7.0662963390e-01f;
|
|
|
|
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)
|
|
{
|
|
// dpgeorge: s was double in original implementation
|
|
float s,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_hi + 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 = sqrtf(z);
|
|
x = pio2_hi - (2*(s+s*R(z)) - pio2_lo); // dpgeorge: use pio2_hi and pio2_lo
|
|
if (hx >> 31)
|
|
return -x;
|
|
return x;
|
|
}
|
|
|
|
/*****************************************************************************/
|
|
/*****************************************************************************/
|
|
// acosf from musl-0.9.15
|
|
/*****************************************************************************/
|
|
/*****************************************************************************/
|
|
|
|
/* origin: FreeBSD /usr/src/lib/msun/src/e_acosf.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.
|
|
* ====================================================
|
|
*/
|
|
|
|
float acosf(float x)
|
|
{
|
|
float z,w,s,c,df;
|
|
uint32_t hx,ix;
|
|
|
|
GET_FLOAT_WORD(hx, x);
|
|
ix = hx & 0x7fffffff;
|
|
/* |x| >= 1 or nan */
|
|
if (ix >= 0x3f800000) {
|
|
if (ix == 0x3f800000) {
|
|
if (hx >> 31)
|
|
return 2*pio2_hi + 0x1p-120f;
|
|
return 0;
|
|
}
|
|
return 0/(x-x);
|
|
}
|
|
/* |x| < 0.5 */
|
|
if (ix < 0x3f000000) {
|
|
if (ix <= 0x32800000) /* |x| < 2**-26 */
|
|
return pio2_hi + 0x1p-120f;
|
|
return pio2_hi - (x - (pio2_lo-x*R(x*x)));
|
|
}
|
|
/* x < -0.5 */
|
|
if (hx >> 31) {
|
|
z = (1+x)*0.5f;
|
|
s = sqrtf(z);
|
|
w = R(z)*s-pio2_lo;
|
|
return 2*(pio2_hi - (s+w));
|
|
}
|
|
/* x > 0.5 */
|
|
z = (1-x)*0.5f;
|
|
s = sqrtf(z);
|
|
GET_FLOAT_WORD(hx,s);
|
|
SET_FLOAT_WORD(df,hx&0xfffff000);
|
|
c = (z-df*df)/(s+df);
|
|
w = R(z)*s+c;
|
|
return 2*(df+w);
|
|
}
|