Showing changes from revision #3 to #4:
Added | Removed | Changed
Offset | Contents |
---|---|
+0 | Pointer to scheduler |
On entry, the following registers are passed from SoundDMA:
Register | Contents |
---|---|
R12 | Pointer to Scheduler (value of R4 in Sound_Configure) |
R13 | IRQ stack |
R14 | Return address |
On return to SoundDMA:
Register | Contents |
---|---|
R1-R7 | Must be preserved |
R8-R12 | May be corrupted |
The Scheduler implements the queue as a circular chain of records. A stack listing the free slots is also kept. The number of free slots varies not only according to how many events are queued, but also to how the events are ‘clustered’.
The queue is always accessed through the SWI calls provided, and so its precise format is not defined.