summaryrefslogtreecommitdiffstats
path: root/usr.sbin/xntpd/lib/tsftomsu.c
blob: 9904b4f5de175936a90e07fb89a48e2158773418 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
/*
 * tsftomsu - convert from a time stamp fraction to milliseconds
 */
#include "ntp_fp.h"
#include "ntp_stdlib.h"

int
tsftomsu(tsf, round)
	u_long tsf;
	int round;
{
	register long val_ui, val_uf;
	register long tmp_ui, tmp_uf;
	register int i;

	/*
	 * Essentially, multiply by 10 three times in l_fp form.
	 * The integral part is the milliseconds.
	 */
	val_ui = 0;
	val_uf = tsf;
	for (i = 3; i > 0; i--) {
		M_LSHIFT(val_ui, val_uf);
		tmp_ui = val_ui;
		tmp_uf = val_uf;
		M_LSHIFT(val_ui, val_uf);
		M_LSHIFT(val_ui, val_uf);
		M_ADD(val_ui, val_uf, tmp_ui, tmp_uf);
	}

	/*
	 * Round the value if need be, then return it.
	 */
	if (round && (val_uf & 0x80000000))
		val_ui++;
	return (int)val_ui;
}
OpenPOWER on IntegriCloud