altera timer hal overflow question ?

do altera hal timers work correct if the end of the system tick

variable range is reached ? Please check the following and tell me

if I'm wrong.

see files alt_tick.c, alt_alarm_start.c,

/*

* "_alt_nticks" is the number of system clock ticks that have elapsed since

* reset.

*/

volatile alt_u32 _alt_nticks = 0;

--> this will result in an overflow after about 49,71.. days

if the system clock timer is set to 1ms,

which is ok for a pc (normally shut off before 49 days),

but an embedded system will normally run longer.

what happens with the timers when an overflow condition exist ???

e.g. to simplify we use a range of 255 ticks and an periodic timer of

10 ticks.

callbacks are run if (alarm->time <= _alt_nticks) is true

so timer will run

ticks

000 system starts

...

010 (10<=10)-> first callback

(timer is rescheduled with alarmtime=alarmtime+10=20)

...

020 (20<=20)-> second callback

(timer is rescheduled with alarmtime=alarmtime+10=30)

...

...

...

250 (250<=250)-->x&#39; callback

(timer is rescheduled with alarmtime=alarmtime+10

overflow will result in alarmtime=4)

251 (4<=251)-->callback

(timer is rescheduled with alarmtime=alarmtime+10

overflow will result in alarmtime=14)

252 (14<=252)-->callback

(timer is rescheduled with alarmtime=alarmtime+10

overflow will result in alarmtime=24)

253 (24<=253)-->callback

(timer is rescheduled with alarmtime=alarmtime+10

overflow will result in alarmtime=34)

254 (34<=254)-->callback

(timer is rescheduled with alarmtime=alarmtime+10

overflow will result in alarmtime=44)

255 (44<=255)--> callback

(timer is rescheduled with alarmtime=alarmtime+10

overflow will result in alarmtime=54)

000 (54<=000) is false

...

054 (54<=54) -> callback

in the range of (tick_range - alarmtime) callbacks are executed

every tick instead of alarmtime ticks, on alt_tick overflow, timer

will be suspended for (alarmtime*alarmtime ticks).

e.g. a periodic timer with 1000ms and a system timer tick of 1ms

after 49,71 days the following will happen

the timer will run 1000 times every 1ms just before _alt_nticks overruns,

then it will need (1000*1000) ms = 1000sec = 16,66 minutes

until the timer will start again.

is this correct or I&#39;m wrong ???