#include <alarm.h>
Inheritance diagram for Alarm::
Public Methods | |
| Alarm (bool doRandomYield) | |
| Initialize the timer, and callback to "toCall" every time slice. More... | |
| ~Alarm () | |
| void | WaitUntil (int x) |
| suspend execution until time > now + x. More... | |
Private Methods | |
| void | CallBack () |
| called when the hardware timer generates an interrupt. More... | |
Private Attributes | |
| Timer* | timer |
| the hardware timer device. More... | |
Definition at line 26 of file alarm.h.
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Initialize the timer, and callback to "toCall" every time slice. Alarm::Alarm Initialize a software alarm clock. Start up a timer device "doRandom" -- if true, arrange for the hardware interrupts to occur at random, instead of fixed, intervals. |
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called when the hardware timer generates an interrupt. Alarm::CallBack Software interrupt handler for the timer device. The timer device is set up to interrupt the CPU periodically (once every TimerTicks). This routine is called each time there is a timer interrupt, with interrupts disabled. Note that instead of calling Yield() directly (which would suspend the interrupt handler, not the interrupted thread which is what we wanted to context switch), we set a flag so that once the interrupt handler is done, it will appear as if the interrupted thread called Yield at the point it is was interrupted. For now, just provide time-slicing. Only need to time slice if we're currently running something (in other words, not idle). Also, to keep from looping forever, we check if there's nothing on the ready list, and there are no other pending interrupts. In this case, we can safely halt. Reimplemented from CallBackObj. |
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suspend execution until time > now + x.
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the hardware timer device.
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1.2.8.1 written by Dimitri van Heesch,
© 1997-2001