Module timer 

Interval timer support (ITIMER_REAL, ITIMER_VIRTUAL, ITIMER_PROF)

POSIX interval timers allow processes to receive periodic signals. Three types are supported:

• ITIMER_REAL: Real (wall clock) time, sends SIGALRM
• ITIMER_VIRTUAL: Process CPU time, sends SIGVTALRM (not yet impl)
• ITIMER_PROF: Process + system CPU time, sends SIGPROF (not yet impl)

Structs

ITimerState

Per-task interval timer state

ITimerVal

Interval timer specification (matches POSIX itimerval)

ITimers

Container for all three interval timers

TimeVal

Time value (seconds + microseconds)

Enums

ITimerWhich

Interval timer types

Functions

tick_all_timers

Global timer tick function to be called from timer interrupt handler. Checks all tasks for expired interval timers and delivers signals.