mirror of
https://github.com/reactos/reactos.git
synced 2024-12-28 18:15:11 +00:00
147 lines
4.5 KiB
C
147 lines
4.5 KiB
C
|
|
/*******************************************************************************
|
|
MIT License
|
|
-----------
|
|
|
|
Copyright (c) 2002-2019 Advanced Micro Devices, Inc.
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this Software and associated documentaon files (the "Software"), to deal
|
|
in the Software without restriction, including without limitation the rights
|
|
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
copies of the Software, and to permit persons to whom the Software is
|
|
furnished to do so, subject to the following conditions:
|
|
|
|
The above copyright notice and this permission notice shall be included in
|
|
all copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
THE SOFTWARE.
|
|
*******************************************************************************/
|
|
|
|
#include "libm.h"
|
|
#include "libm_util.h"
|
|
|
|
#define USE_VALF_WITH_FLAGS
|
|
#define USE_NANF_WITH_FLAGS
|
|
#define USE_HANDLE_ERRORF
|
|
#include "libm_inlines.h"
|
|
#undef USE_NANF_WITH_FLAGS
|
|
#undef USE_VALF_WITH_FLAGS
|
|
#undef USE_HANDLE_ERRORF
|
|
|
|
#include "libm_errno.h"
|
|
|
|
#ifdef _MSC_VER
|
|
// Disable "C4163: not available as intrinsic function" warning that older
|
|
// compilers may issue here.
|
|
#pragma warning(disable:4163)
|
|
#pragma function(acosf)
|
|
#endif
|
|
|
|
float FN_PROTOTYPE(acosf)(float x)
|
|
{
|
|
/* Computes arccos(x).
|
|
The argument is first reduced by noting that arccos(x)
|
|
is invalid for abs(x) > 1. For denormal and small
|
|
arguments arccos(x) = pi/2 to machine accuracy.
|
|
Remaining argument ranges are handled as follows.
|
|
For abs(x) <= 0.5 use
|
|
arccos(x) = pi/2 - arcsin(x)
|
|
= pi/2 - (x + x^3*R(x^2))
|
|
where R(x^2) is a rational minimax approximation to
|
|
(arcsin(x) - x)/x^3.
|
|
For abs(x) > 0.5 exploit the identity:
|
|
arccos(x) = pi - 2*arcsin(sqrt(1-x)/2)
|
|
together with the above rational approximation, and
|
|
reconstruct the terms carefully.
|
|
*/
|
|
|
|
/* Some constants and split constants. */
|
|
|
|
static const float
|
|
piby2 = 1.5707963705e+00F; /* 0x3fc90fdb */
|
|
static const double
|
|
pi = 3.1415926535897933e+00, /* 0x400921fb54442d18 */
|
|
piby2_head = 1.5707963267948965580e+00, /* 0x3ff921fb54442d18 */
|
|
piby2_tail = 6.12323399573676603587e-17; /* 0x3c91a62633145c07 */
|
|
|
|
float u, y, s = 0.0F, r;
|
|
int xexp, xnan, transform = 0;
|
|
|
|
unsigned int ux, aux, xneg;
|
|
|
|
GET_BITS_SP32(x, ux);
|
|
aux = ux & ~SIGNBIT_SP32;
|
|
xneg = (ux & SIGNBIT_SP32);
|
|
xnan = (aux > PINFBITPATT_SP32);
|
|
xexp = (int)((ux & EXPBITS_SP32) >> EXPSHIFTBITS_SP32) - EXPBIAS_SP32;
|
|
|
|
/* Special cases */
|
|
|
|
if (xnan)
|
|
{
|
|
return _handle_errorf("acosf", OP_ACOS, ux|0x00400000, _DOMAIN, 0,
|
|
EDOM, x, 0.0F, 1);
|
|
}
|
|
else if (xexp < -26)
|
|
/* y small enough that arccos(x) = pi/2 */
|
|
return valf_with_flags(piby2, AMD_F_INEXACT);
|
|
else if (xexp >= 0)
|
|
{ /* abs(x) >= 1.0 */
|
|
if (x == 1.0F)
|
|
return 0.0F;
|
|
else if (x == -1.0F)
|
|
return valf_with_flags((float)pi, AMD_F_INEXACT);
|
|
else
|
|
return _handle_errorf("acosf", OP_ACOS, INDEFBITPATT_SP32, _DOMAIN,
|
|
AMD_F_INVALID, EDOM, x, 0.0F, 1);
|
|
}
|
|
|
|
if (xneg) y = -x;
|
|
else y = x;
|
|
|
|
transform = (xexp >= -1); /* abs(x) >= 0.5 */
|
|
|
|
if (transform)
|
|
{ /* Transform y into the range [0,0.5) */
|
|
r = 0.5F*(1.0F - y);
|
|
/* VC++ intrinsic call */
|
|
_mm_store_ss(&s, _mm_sqrt_ss(_mm_load_ss(&r)));
|
|
y = s;
|
|
}
|
|
else
|
|
r = y*y;
|
|
|
|
/* Use a rational approximation for [0.0, 0.5] */
|
|
|
|
u=r*(0.184161606965100694821398249421F +
|
|
(-0.0565298683201845211985026327361F +
|
|
(-0.0133819288943925804214011424456F -
|
|
0.00396137437848476485201154797087F*r)*r)*r)/
|
|
(1.10496961524520294485512696706F -
|
|
0.836411276854206731913362287293F*r);
|
|
|
|
if (transform)
|
|
{
|
|
/* Reconstruct acos carefully in transformed region */
|
|
if (xneg)
|
|
return (float)(pi - 2.0*(s+(y*u - piby2_tail)));
|
|
else
|
|
{
|
|
float c, s1;
|
|
unsigned int us;
|
|
GET_BITS_SP32(s, us);
|
|
PUT_BITS_SP32(0xffff0000 & us, s1);
|
|
c = (r-s1*s1)/(s+s1);
|
|
return 2.0F*s1 + (2.0F*c+2.0F*y*u);
|
|
}
|
|
}
|
|
else
|
|
return (float)(piby2_head - (x - (piby2_tail - x*u)));
|
|
}
|