nuttx/libs/libc/math/lib_trunc.c
Xiang Xiao 6a3c2aded6 Fix wait loop and void cast (#24)
* Simplify EINTR/ECANCEL error handling

1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx

* Unify the void cast usage

1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro
2020-01-02 10:54:43 -06:00

84 lines
2.3 KiB
C

/****************************************************************************
* libs/libc/math/lib_trunc.c
*
* This implementation is derived from the musl library under the MIT License
*
* Copyright © 2005-2014 Rich Felker, et al.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <stdint.h>
#include <math.h>
/****************************************************************************
* Public Functions
****************************************************************************/
#ifdef CONFIG_HAVE_DOUBLE
double trunc(double x)
{
union
{
double f;
uint64_t i;
} u =
{
x
};
int e = (int)(u.i >> 52 & 0x7ff) - 0x3ff + 12;
uint64_t m;
volatile float __x;
if (e >= 52 + 12)
{
return x;
}
if (e < 12)
{
e = 1;
}
m = -1ull >> e;
if ((u.i & m) == 0)
{
return x;
}
/* Force Evaluation */
__x = (x + 0x1p120f);
UNUSED(__x);
u.i &= ~m;
return u.f;
}
#endif