nsz
0cbb654791
zero, one, two, half are replaced by const literals The policy was to use the f suffix for float consts (1.0f), but don't use suffix for long double consts (these consts can be exactly represented as double).
43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
/* origin: FreeBSD /usr/src/lib/msun/src/e_acoshf.c */
|
|
/*
|
|
* Conversion to float by Ian Lance Taylor, Cygnus Support, [email protected].
|
|
*/
|
|
/*
|
|
* ====================================================
|
|
* 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
|
|
ln2 = 6.9314718246e-01; /* 0x3f317218 */
|
|
|
|
float acoshf(float x)
|
|
{
|
|
float t;
|
|
int32_t hx;
|
|
|
|
GET_FLOAT_WORD(hx, x);
|
|
if (hx < 0x3f800000) { /* x < 1 */
|
|
return (x-x)/(x-x);
|
|
} else if (hx >= 0x4d800000) { /* x > 2**28 */
|
|
if (hx >= 0x7f800000) /* x is inf of NaN */
|
|
return x + x;
|
|
return logf(x) + ln2; /* acosh(huge)=log(2x) */
|
|
} else if (hx == 0x3f800000) {
|
|
return 0.0f; /* acosh(1) = 0 */
|
|
} else if (hx > 0x40000000) { /* 2**28 > x > 2 */
|
|
t = x*x;
|
|
return logf(2.0f*x - 1.0f/(x+sqrtf(t-1.0f)));
|
|
} else { /* 1 < x < 2 */
|
|
t = x-1.0f;
|
|
return log1pf(t + sqrtf(2.0f*t+t*t));
|
|
}
|
|
}
|