ADFS_IDEUserOp (changes)
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ADFS
» SWI Calls
» ADFS_IDEUserOp
ADFS_IDEUserOp
(SWI &4024B)
| Entry | |
|---|---|
| R0 | Flag bits |
| R2 | Pointer to Parameter block for command and results |
| R3 | Pointer to buffer |
| R4 | Length to transfer |
| R5 | Timeout in centiseconds (if 0 is passed then use the default value) |
| R12 | Pointer to static workspace |
| Exit | |
|---|---|
| R0 | Command status (0 or a disc error number) |
| R2 | Preserved |
| R3 | Preserved |
| R4 | Updated |
| R5 | Corrupted |
Flag bits
| 0 | 0 = process command |
| 1 = reset controller | |
| 3 | 1 = parameter block pointed to by R2 is 11 bytes long (new in ADFS 3.34 / RISC OS 5.02) |
| 12 – 15 | device ID (since ADFS 4.00) |
| 16 – 23 | controller/port ID (since ADFS 3.34 / RISC OS 5.02) |
| 24 – 25 | 00 = no transfer |
| 01 = read (bit 24 set) | |
| 10 = write (bit 25 set) | |
| 11 = reserved |
| 26 | 1 = 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 3.34 / RISC OS 5.02) |
Parameter block
Original form (R0 bit 3 clear):CHS/28-bit LBA form (R0 bit 3 clear):
| +0 | Features/Error |
| +1 | Sector Count |
| +2 | LBA |
| +3 | LBA |
| +4 | LBA |
| +5 | |
| bits 0-3 – LBA bits 24-27/Head | |
| bit 4 – 0=master, 1=slave | |
| bit 6 – 0=CHS mode, 1=LBA mode | |
| +6 | Command/Status |
48-bit LBA form (R0 bit 3 set, since ADFS 3.34 / RISC OS 5.02):
| +0 | Features/Error |
| +1 | 16-bit Sector Count |
| +3 | 48-bit LBA |
| +9 | |
| bit 4 – 0=master, 1=slave | |
| bit 6 – 0=CHS mode, 1=LBA mode | |
| +10 | Command/Status |
Since ADFS 4.00, the use of bit 4 of the Device byte of the parameter block to select between devices on the same controller/port is deprecated (even for PATA controllers; PATADriver will substitute the device number into the Device byte prior to transmission for you). Use bits 12-15 of R0 instead. Also since ADFS 4.00, the parameter block is no longer updated if R0 bit 0 was set on entry.
Use
The purpose of this call is to access low-level IDE commands.
Notes
This call must not be called in the background.
See also
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