freebsd-dev/usr.sbin/xntpd/lib/tsftomsu.c
1993-12-21 18:36:48 +00:00

38 lines
759 B
C

/* tsftomsu.c,v 3.1 1993/07/06 01:08:47 jbj Exp
* 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 U_LONG val_ui, val_uf;
register U_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;
}