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fix microtime()

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This commit is contained in:
msaitoh 2001-06-24 05:00:28 +00:00
parent a76500b70d
commit 33b63f3efa
1 changed files with 32 additions and 1 deletions
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33
sys/arch/sh3/sh3/clock.c
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@ -1,4 +1,4 @@
/* $NetBSD: clock.c,v 1.15 2001/04/23 11:20:41 uch Exp $ */
/* $NetBSD: clock.c,v 1.16 2001/06/24 05:00:28 msaitoh Exp $ */
/*-
* Copyright (c) 1993, 1994 Charles Hannum.
@ -142,9 +142,39 @@ microtime(tvp)
{
int s = splclock();
static struct timeval lasttime;
static u_long numerator = 0;
static u_long denominator = 0;
/*
* 1/hz resolution ``time'' which is counted up at hardclock().
*/
*tvp = time;
/*
* diff = (PCLOCK/16/hz - 1 - SHREG_TCNT1) / (PCLOCK/16/hz - 1)
* * 1/hz * 10^6. [usec]
*/
if (denominator == 0) {
numerator = 1000000 / hz;
denominator = PCLOCK/16/hz - 1;
}
diff = (denominator - SHREG_TCNT1) * numerator / denominator;
/*
* add ``diff'' to ``time''
*/
tvp->tv_usec += diff;
while (tvp->tv_usec >= 1000000) {
tvp->tv_usec -= 1000000;
tvp->tv_sec++;
}
/*
* microtime() always gains 1usec at least.
*/
if (tvp->tv_sec == lasttime.tv_sec &&
tvp->tv_usec <= lasttime.tv_usec &&
(tvp->tv_usec = lasttime.tv_usec + 1) >= 1000000) {
@ -152,6 +182,7 @@ microtime(tvp)
tvp->tv_usec -= 1000000;
}
lasttime = *tvp;
splx(s);
}