ADFS_ATAPIOp (changes)
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ADFS
» SWI Calls
» ADFS_ATAPIOp
ADFS_ATAPIOp
(SWI &40255)
| Entry | |
|---|---|
| R0 | bit 0 set => reset controller |
| bit 0 clear => process command; other bits then act as below | |
| bits 12-15 = device ID (prior to ADFS 4.00, only device IDs 0 and 8 were valid, corresponding to master and slave PATA devices) | |
| bits 16-23 = controller/port ID | |
| bits 24-25 = transfer direction: | |
| 00 => no transfer | |
| 01 => read (ie bit 24 set) | |
| 10 => write (ie bit 25 set) | |
| 11 reserved | |
| bit 26 set => data transfer uses multiword DMA or UDMA from device’s perspective (note that the host controller may actually use bus mastering even for PIO transfers) (since ADFS 4.00) | |
| bit 27 set => device requires DMADIR indicator in Features task file register (determine this using IDENTIFY PACKET DEVICE) (since ADFS 4.00) | |
| R1 | length of Control block – must be 12 or 16 (prior to ADFS 4.00, must be 12) |
| R2 | pointer to Control block |
| R3 | pointer to buffer |
| R4 | length to transfer |
| R5 | timeout in centiseconds (0 => use default, currently 10 seconds) |
| Exit | |
|---|---|
| R0 | 0 if successful, or a disc error number (with V flag clear) |
| R1 | Preserved? |
| R2 | Preserved? The Control block is not updated |
| R3 | Pointer to first byte not transferred |
| R4 | Length not transferred |
| R5 | Corrupted |
Control block (12 byte format)
| Offset | Description |
|---|---|
| +0 | Operation code |
| +1 | Service action |
| +2 | 32-bit LBA |
| +6 | 32-bit Length |
| +10 | Reserved |
| +11 | Control |
Use
The purpose of this call is to perform ATA operations on ADFS attached devices.
Notes
This SWI was first present in ADFS 3.34 (RISC OS 5.02)
See also
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