DMA_QueueTransfer
DMAManager
» SWI Calls
» DMA_QueueTransfer
DMA_QueueTransfer
(SWI &46142)
| Entry | |
|---|---|
| R0 | Flags: |
| Bit 0: 1=write transfer (memory to device), 0=read transfer (device to memory) | |
| Bit 1: 1=scatter list is a circular buffer, 0=not circular | |
| Bit 2: 1=call DMASync control routine, 0=don’t call | |
| Bits 3-31: Reserved (set to 0) | |
| R1 | Channel handle |
| R2 | Value of R11 to be passed to control routines |
| R3 | Pointer to word aligned scatter list |
| R4 | Number of bytes to transfer, or 0 for infinite length transfer (if bit 1 of R0 set) |
| R5 | Size of circular buffer (if bit 1 of R0 set) |
| R6 | Number of bytes between calls to DMASync control routine (if bit 2 of R0 set) |
| Exit | |
|---|---|
| R0 | DMA tag |
| - | Other registers preserved |
Use
Queues a DMA transfer request for a logical channel.
The returned DMA tag can be used with other DMAManager SWIs such as DMA_ExamineTransfer and DMA_TerminateTransfer in order to examine or control the state of the transfer.
Notes
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).
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