Setting timer timestamp

Hi there,

Recently, I had been working on TimerInit() and TimerDiff(), and I met a problem, so after I start a new TimerInit(), after a few mins of running, i need to change the timestamp of the timer and make it run from the time I provided..

Example: TimerInit() at 0s
At 5s, I change the timestamp to 1m 17s, I want the timer to continue running on going, 1m 18s, 1m 19s.. and so on..

Anyone knows a solution for this?