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HAL_IRQClear
Hardware Abstraction Layer
HAL entry points from RISC OS
» HAL_IRQClear
HAL_IRQClear
(HAL entry #3)
void HAL_IRQClear(int device)
| Entry | |
|---|---|
| device | Device number to clear interrupt state for |
| Exit | |
|---|---|
| - |
Use
This call has a dual purpose:
- To clear the interrupt state of latched interrupt sources – typically for edge-triggered interrupts and certain integrated devices such as
- Timers (as reported by HAL_TimerDevice)
- VSync (as reported by HAL_VideoFlybackDevice)
- To trigger the interrupt controller to start looking for new interrupt sources (required for interrupt controllers that latch the device number of the interrupt source, and thus could claim that the device is still interrupting even if it’s been successfully serviced).
Because of point 2, this means that all interrupt service routines must call this routine after servicing the device. Current versions of the kernel will not call HAL_IRQClear for you – it is your responsibility to do so yourself. This is new functionality added for the Cortex/OMAP3 port, to account for the behaviour of the OMAP3 interrupt controller.