linuxptp/tmtab.c

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/**
* @file tmtab.c
* @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "tmtab.h"
#include "tmv.h"
void tmtab_init(struct tmtab *tt, int log_seconds)
{
int i;
struct timespec incr, ts = {0, 0};
uint64_t max, min;
if (log_seconds < 0) {
log_seconds *= -1;
for (i = 1, max = 500000000ULL; i < log_seconds; i++) {
max >>= 1;
}
} else {
for (i = 0, max = 1000000000ULL; i < log_seconds; i++) {
max <<= 1;
}
}
min = max / (TMTAB_MAX - 1ULL);
incr.tv_sec = min / 1000000000ULL;
incr.tv_nsec = min % 1000000000ULL;
for (i = 0; i < TMTAB_MAX; i++) {
ts.tv_sec += incr.tv_sec;
ts.tv_nsec += incr.tv_nsec;
while (ts.tv_nsec >= NS_PER_SEC) {
ts.tv_nsec -= NS_PER_SEC;
ts.tv_sec++;
}
tt->ts[i] = ts;
}
}