Showing changes from revision #1 to #2:
Added | Removed | Changed
Entry | |
---|---|
R0 | 12 |
R1 | Pointer to word-aligned buffer, or 0 to read required buffer size |
Exit | |
---|---|
R0 | Size of extended ID, or 0 if extended ID not present/corrupt |
R1 | Preserved. If the buffer pointer was supplied, the extended ID will have been copied into it. |
For machines which provide machine IDs that differ from Acorn’s traditional ID format, this call allows you to read the full, unmodified ID.
For compatability with old software, if a machine’s HAL provides an extended ID then the kernel will use that extended ID to synthesise an Acorn-style machine ID. This synthesised ID will be then be returned by any calls to OS_ReadSysInfo 2/OS_ReadSysInfo 5.
Because of this behaviour it is recommended that new software should first attempt to read the extended ID via OS_ReadSysInfo 12 before falling back on the ID returned by OS_ReadSysInfo 2/5. This will help to ensure the uniqueness of the ID that the program uses.
This call first became available in RISC OS 5.17.