DMA_ExamineTransfer (changes)
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DMAManager
» SWI Calls
» DMA_ExamineTransfer
DMA_ExamineTransfer
(SWI &46146)
| Entry | |
|---|---|
| R0 | Flags: |
| Bits 0-31: Reserved (set to 0) | |
| R1 | DMA tag |
| Exit | |
|---|---|
| R0 | Number of bytes transferred so far |
| - | All other registers preserved |
Use
This SWI is used to return the progress of a DMA transfer, giving the total number of bytes transferred. This will be a pessimistic figure, indicating the number of bytes that DMAManager can say for certainty have been transferred. Depending on how frequently the underlyingDMA driver provides progress updates, the value may lag quite far behind the actual progress.
Notes
An error block is returned if the DMA tag is invalid.
This documentation only covers the RISC OS 5 version of the DMAManager SWIs. For other OS versions, consult the appropriate PRM volume (e.g. volume 5a).
See also
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