OSWORD &FB
OSWORD &FB (251) Floppy disk access
This OSWORD call is installed by the 80x86 DOS BIOS.
Commands are sent from the 80x86 via Tube Register 2 within the OSWORD protocol, so cannot be called through the normal OSWORD mechanism. The transaction must be done manually by the client by sending through Tube Register 2:
&08 : Start OSWORD transaction &FB : OSWORD call &FB &00 : TxLen=0 xxx : Send a series of commands &00 : RxLen=0, terminate the OSWORD call
Commands
- &00 : Finish
- &01 : Master FDC command
- &02 : BBC B/B+ command
- &03 : Claim Tube and NMI
- &04 : Release Tube and NMI
- &nn,&mm : Write byte &mm to &FE00+nn
FDC commands
The FDC commands &01 and &02 are followed by a parameter block:
- address b0-b7
- address b8-b15
- address b16-b23
- address b24-b31
- &00=Read from disk, <>&00-Write to disk
- error mask
- sector count
- FDC command
The initial drive, track, sector must be written to the FDC hardware beforehand using commands >&04 to write to &FE00+FDC_address.
See also
- OSWORD &FA
- OSWORD &FC
- OSWORD &FD
- OSWORD &FE
- OSWORD &FF
- OSWORD &FB source code
- OSWORDs list at mdfs.net
Jgharston 14:27, 26 May 2009 (UTC) Jgharston (talk) 10:54, 17 December 2024 (CET)
