OS_CallAfter (changes)
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Programmer's OS Reference SWI Manuals Calls
» OS_CallAfterPart 15 – SWI Calls
» OS
» OS_CallAfter
OS_CallAfter
(SWI &3B)
| Entry | |
|---|---|
| R0 | Delay in centi-seconds |
| R1 | Address to call |
| R2 | Value of R12 to call code with |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
| R2 | Preserved |
Use
The purpose of this call is to call a specified memory address after a delay, in centi-seconds.
Notes
The routine will be called on the (R0+1)th clock tick to be seen once the routine has been registered. E.g. if R0 is 10 then it’s guaranteed that a full 10 centiseconds will have passed before the routine is called. The minimum supported R0 value is 1.
A routine called by this mechanism is called in SVC mode with interrupts disabled, must preserve ALL registers and return by MOV PC, R14. The routine can enable interrupts, but must take care to restore the previous state on exit.
To cancel the settings of this call, use OS_RemoveTickerEvent.
See also
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