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FileCore_DiscOp 9
Programmer's Reference Manuals
» Part 15 – SWI Calls
» FileCore
» FileCore_DiscOp
» FileCore_DiscOp 9
FileCore_DiscOp 9
(SWI &40540)
| Entry | |
|---|---|
| R1 | 9 + Flags |
| R2 | Disc address |
| R3 | Pointer to block to read into |
| R4 | Size to read |
| R6 | Cache handle |
| Exit | |
|---|---|
| R1 | Preserved |
| R2 | Next disc address |
| R3 | Next free address |
| R4 | Unread bytes |
| R6 | Cache handle |
Use
The purpose of this call is to read sectors via a cache held in RMA memory.
Notes
To start a sequence of these operations, set R6 (cache handle) to zero on entry. Its value will be updated on exit, and subsequent calls should use this new values. Bits 4-7 of R1 should be zero, but are ignored if set.
To discard the cache once finished, just call FileCore_DiscardReadSectorsCache.
Note: For RISC OS 3.60, the value in R2 will be rounded down to be sector aligned.