nuttx/libs/libc/math/lib_rintl.c
Alin Jerpelea b7c451c5a4 libs: Gregory Nutt: update licenses to Apache
Gregory Nutt has submitted the SGA and we can migrate the licenses
 to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-04-02 11:12:25 -05:00

125 lines
3.9 KiB
C

/****************************************************************************
* libs/libc/math/lib_rintl.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 Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
long double rintl(long double x)
{
int64_t llinteger;
long double fremainder;
long 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.
*/
llinteger = (int64_t)x;
fremainder = x - (long double)llinteger;
if (x < 0.0)
{
/* fremainder should be in range 0 .. -1 */
if (fremainder == -0.5)
{
llinteger = ((llinteger + 1) & ~1);
}
else if (fremainder < -0.5)
{
llinteger--;
}
}
else
{
/* fremainder should be in range 0 .. 1 */
if (fremainder == 0.5)
{
llinteger = ((llinteger + 1) & ~1);
}
else if (fremainder > 0.5)
{
llinteger++;
}
}
ret = (long double)llinteger;
#endif
return ret;
}