[src/sommerfeld_i386mp_1]: src/sys/arch/i386/i386 avoid division by zero if l...

[sommerfeld <sommerfeld%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/49e7bbfcaa2b
branches:  sommerfeld_i386mp_1
changeset: 482190:49e7bbfcaa2b
user:      sommerfeld <sommerfeld%NetBSD.org@localhost>
date:      Mon Feb 21 19:32:32 2000 +0000

description:
avoid division by zero if lapic timer isn't moving.

diffstat:

 sys/arch/i386/i386/lapic.c |  71 +++++++++++++++++++++++----------------------
 1 files changed, 37 insertions(+), 34 deletions(-)

diffs (90 lines):

diff -r fcb47fdc4fe3 -r 49e7bbfcaa2b sys/arch/i386/i386/lapic.c
--- a/sys/arch/i386/i386/lapic.c        Mon Feb 21 18:54:07 2000 +0000
+++ b/sys/arch/i386/i386/lapic.c        Mon Feb 21 19:32:32 2000 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: lapic.c,v 1.1.2.4 2000/02/21 18:51:00 sommerfeld Exp $ */
+/* $NetBSD: lapic.c,v 1.1.2.5 2000/02/21 19:32:32 sommerfeld Exp $ */
 
 /*-
  * Copyright (c) 2000 The NetBSD Foundation, Inc.
@@ -296,44 +296,47 @@
           
        printf("%s: apic clock running at %s\n", ci->ci_dev.dv_xname, tbuf);
 
-       /*
-        * reprogram the apic timer to run in periodic mode.
-        * XXX need to program timer on other cpu's, too.
-        */
-       lapic_tval = (lapic_per_second * 2) / hz;
-       lapic_tval = (lapic_tval / 2) + (lapic_tval & 0x1);
+       if (lapic_per_second != 0) {
+               /*
+                * reprogram the apic timer to run in periodic mode.
+                * XXX need to program timer on other cpu's, too.
+                */
+               lapic_tval = (lapic_per_second * 2) / hz;
+               lapic_tval = (lapic_tval / 2) + (lapic_tval & 0x1);
        
-       i82489_writereg (LAPIC_LVTT, LAPIC_LVTT_TM|LAPIC_LVTT_M
-           |LAPIC_TIMER_VECTOR);
-       i82489_writereg (LAPIC_DCR_TIMER, LAPIC_DCRT_DIV1);
-       i82489_writereg (LAPIC_ICR_TIMER, lapic_tval);
+               i82489_writereg (LAPIC_LVTT, LAPIC_LVTT_TM|LAPIC_LVTT_M
+                   |LAPIC_TIMER_VECTOR);
+               i82489_writereg (LAPIC_DCR_TIMER, LAPIC_DCRT_DIV1);
+               i82489_writereg (LAPIC_ICR_TIMER, lapic_tval);
 
-       /*
-        * Compute fixed-point ratios between cycles and
-        * microseconds to avoid having to do any division
-        * in lapic_delay and lapic_microtime.
-        */
+               /*
+                * Compute fixed-point ratios between cycles and
+                * microseconds to avoid having to do any division
+                * in lapic_delay and lapic_microtime.
+                */
 
-       tmp = (1000000 * (u_int64_t)1<<32) / lapic_per_second;
-       lapic_frac_usec_per_cycle = tmp;
-
-       tmp = (lapic_per_second * (u_int64_t)1<<32) / 1000000;
-
-       lapic_frac_cycle_per_usec = tmp;
+               tmp = (1000000 * (u_int64_t)1<<32) / lapic_per_second;
+               lapic_frac_usec_per_cycle = tmp;
+               
+               tmp = (lapic_per_second * (u_int64_t)1<<32) / 1000000;
+               
+               lapic_frac_cycle_per_usec = tmp;
        
-       /*
-        * Compute delay in cycles for likely short delays in usec.
-        */
-       for (i=0; i<26; i++)
-               lapic_delaytab[i] = (lapic_frac_cycle_per_usec * i) >> 32;
+               /*
+                * Compute delay in cycles for likely short delays in usec.
+                */
+               for (i=0; i<26; i++)
+                       lapic_delaytab[i] = (lapic_frac_cycle_per_usec * i) >>
+                           32;
 
-       /*
-        * Now that the timer's calibrated, use the apic timer routines
-        * for all our timing needs..
-        */
-       delay_func = lapic_delay;
-       microtime_func = lapic_microtime;
-       initclock_func = lapic_initclocks;
+               /*
+                * Now that the timer's calibrated, use the apic timer routines
+                * for all our timing needs..
+                */
+               delay_func = lapic_delay;
+               microtime_func = lapic_microtime;
+               initclock_func = lapic_initclocks;
+       }
 }
 
 /*