OS_File 255 (changes)
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OS SWI Calls
» OS_File
» OS_File 255
OS_ File 255
(SWI &08)
| Entry | |
|---|---|
| R0 | |
| R1 | Pointer to filename |
| R2 | Load address if (R3 AND &FF = 0) |
| R3 | Bits 0-7 clear to use R2 as load address, else use file’s load address/filetype |
| Bit 30 is used by the SaferOSFile extension | |
| Bit 31 set to specify the file is code and should be synchronised | |
| R5 | Length of buffer at R2 if R3b30 set and SaferOSFile extension present |
| Exit | |
|---|---|
| R0 | Object type |
| R1 | Preserved |
| R2 | Load address |
| R3 | Execution address |
| R4 | Object length |
| R5 | Object attributes |
Use
The purpose of this call is to load a named file, using File$Path variable.
Notes
An error will be generated if the file is not found, is a directory, no read access, or a bad load address.
If the file is stamped, and loading at load address (R3 AND &FF <> 0) the variable Alias$@LoadType_xxx will be used, and it is possible that (like OS_FSControl 4) this call may not return.
There are several different reason codes that can be used to load files using the OS_File call. They differ depending on how the path used to find the file.
In addition:
- R3 bit 31 is not supported (or necessary) before RISC OS 3.70.
- As of RISC OS 3.71, files stamped &F95 (Code) are always Synchronised after loading
See also
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