125 lines
3.9 KiB
C
125 lines
3.9 KiB
C
/****************************************************************************
|
|
* libs/libc/math/lib_rint.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <stdlib.h>
|
|
#include <math.h>
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Type Declarations
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Function Prototypes
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Constant Data
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Data
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Constant Data
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
double rint(double x)
|
|
{
|
|
long linteger;
|
|
double fremainder;
|
|
double ret;
|
|
|
|
/* If the current rounding mode rounds toward negative
|
|
* infinity, rint() is identical to floor(). If the current
|
|
* rounding mode rounds toward positive infinity, rint() is
|
|
* identical to ceil().
|
|
*/
|
|
|
|
#if defined(CONFIG_FP_ROUND_POSITIVE) && CONFIG_FP_ROUNDING_POSITIVE != 0
|
|
|
|
ret = ceil(x);
|
|
|
|
#elif defined(CONFIG_FP_ROUND_NEGATIVE) && CONFIG_FP_ROUNDING_NEGATIVE != 0
|
|
|
|
ret = floor(x);
|
|
|
|
#else
|
|
|
|
/* In the default rounding mode (round to nearest), rint(x) is the
|
|
* integer nearest x with the additional stipulation that if
|
|
* |rint(x)-x|=1/2, then rint(x) is even.
|
|
*/
|
|
|
|
linteger = (long)x;
|
|
fremainder = x - (double)linteger;
|
|
|
|
if (x < 0.0)
|
|
{
|
|
/* fremainder should be in range 0 .. -1 */
|
|
|
|
if (fremainder == -0.5)
|
|
{
|
|
linteger = ((linteger + 1) & ~1);
|
|
}
|
|
else if (fremainder < -0.5)
|
|
{
|
|
linteger--;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* fremainder should be in range 0 .. 1 */
|
|
|
|
if (fremainder == 0.5)
|
|
{
|
|
linteger = ((linteger + 1) & ~1);
|
|
}
|
|
else if (fremainder > 0.5)
|
|
{
|
|
linteger++;
|
|
}
|
|
}
|
|
|
|
ret = (double)linteger;
|
|
#endif
|
|
|
|
return ret;
|
|
}
|