score/src/timespecdivide.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreTimespec
0007  *
0008  * @brief This source file contains the implementation of
0009  *   _Timespec_Divide().
0010  */
0011
0012 /*
0013  *  COPYRIGHT (c) 1989-2007.
0014  *  On-Line Applications Research Corporation (OAR).
0015  *
0016  * Redistribution and use in source and binary forms, with or without
0017  * modification, are permitted provided that the following conditions
0018  * are met:
0019  * 1. Redistributions of source code must retain the above copyright
0020  *    notice, this list of conditions and the following disclaimer.
0021  * 2. Redistributions in binary form must reproduce the above copyright
0022  *    notice, this list of conditions and the following disclaimer in the
0023  *    documentation and/or other materials provided with the distribution.
0024  *
0025  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0026  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0027  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0028  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0029  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0030  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0031  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0032  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0033  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0034  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0035  * POSSIBILITY OF SUCH DAMAGE.
0036  */
0037
0038 #ifdef HAVE_CONFIG_H
0039 #include "config.h"
0040 #endif
0041
0042 #include <rtems/score/timespec.h>
0043 #include <rtems/score/todimpl.h>
0044
0045 void _Timespec_Divide(
0046   const struct timespec *lhs,
0047   const struct timespec *rhs,
0048   uint32_t              *ival_percentage,
0049   uint32_t              *fval_percentage
0050 )
0051 {
0052   uint64_t left, right, answer;
0053
0054   /*
0055    *  For math simplicity just convert the timespec to nanoseconds
0056    *  in a 64-bit integer.
0057    */
0058   left   = lhs->tv_sec * (uint64_t)TOD_NANOSECONDS_PER_SECOND;
0059   left  += lhs->tv_nsec;
0060   right  = rhs->tv_sec * (uint64_t)TOD_NANOSECONDS_PER_SECOND;
0061   right += rhs->tv_nsec;
0062
0063   if ( right == 0 ) {
0064     *ival_percentage = 0;
0065     *fval_percentage = 0;
0066     return;
0067   }
0068
0069   /*
0070    *  Put it back in the timespec result.
0071    *
0072    *  TODO: Rounding on the last digit of the fval.
0073    */
0074
0075   answer = (left * 100000) / right;
0076
0077   *ival_percentage = answer / 1000;
0078   *fval_percentage = answer % 1000;
0079 }