ImageFS Information Block (changes)
Showing changes from revision #0 to #1:
Added | Removed | Changed
| Offset | Contents | |
|---|---|---|
| &00 | Image filing system information word (see below) | |
| &04 | Image filing system file type | |
| &08 | Offset of routine to open files | (ImageEntry_Open) |
| &0C | Offset of routine to get bytes from media | (ImageEntry_GetBytes) |
| &10 | Offset of routine to put bytes to media | (ImageEntry_PutBytes) |
| &14 | Offset of routine to control open files | (ImageEntry_Args) |
| &18 | Offset of routine to close open files | (ImageEntry_Close) |
| &1C | Offset of routine to do whole file operations | (ImageEntry_File) |
| &24 | Offset of routine to do various FS operations | (ImageEntry_Func?) |
The offsets held in each word are from the base of the filing system module.
The block need not exist for long, as FileSwitch takes a copy of it and converts the entry points to absolute addresses. So you could set up the block as an area in a stack frame, for example.
The image filing system file type gives the numerical file type of files which contain images understood by the image filing system.
Filing system information word
The filing system information word (at offset &00) tells FileSwitch various things about the filing system:
| Bit | Meaning if set |
|---|---|
| 27 | Tell the image filing system when flushing by calling ImageEntry_Args? 255 |
All other bits are reserved and should be set to zero.
See also
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