FSCV
Filing system control
Contents
Specification
This vector is only called by the operating system, and should not be called directly. This list just shows the full list of calls.
Specification
| On entry: | On exit: | |
| A | = function code | Return value, or preserved if function not supported |
| X,Y | =>command string or byte parameters | Any returned data |
| Functions | |
| &00 | *OPT command. X and Y hold parameters. |
| &01 | EOF on channel Y being checked with OSBYTE &7F. On exit, X=&FF if EOF, X=&00 otherwise. If Y=&00, (ie, EOF#0) action is implementation specific. |
| &02 | */ command. XY points to the command text. |
| &03 | Unrecognised OSCLI. XY points to the command text. The command has already been offered to the paged ROMs via service call &04, and none have responded. |
| &04 | *RUN command. XY points to filename. |
| &05 | *CAT command. XY points to any pathname. |
| &06 | A new filing system is about to take over. This call is generated by filing systems themselves before they start their initialisation. |
| &07 | File handle range request. Lowest returned in X, highest in Y. |
| &08 | OSCLI command being processed. This is used to facilitate the *ENABLE command. |
| &09 | *EX command. XY points to any pathname. |
| &0A | *INFO command. XY points to the object name. |
| &0B | *RUN from library. XY points to the filename. |
| &0C | *RENAME command. XY points to the object names after the command. |
Extensions
FSCV can be extended (eg by TubeHost) so that any other calls <&80 pass a string pointed to by X,Y, and calls >&7F pass and receive two bytes of data in X,Y.
| Functions | |
| &FF | Startup, Y=0 to boot filing system, Y<>0 for no boot. X=default return value, &00 for no action. |
Calling from BBC BASIC
-
=EOF#chon 8-bit systems calls OSBYTE 127, which calls FSC &01.
Special handles
Z88 allows:
-
=EOF#-1, returns -1 for expanded and 0 for unexpanded.
Entry points
There is no entry point to FSC. It is called by other parts of the system in response to other calls, and should not be called directly via the vector.
Implementations
- *OPT 0 - resets options to default values.
- *OPT 1 - set message reporting level
- *OPT 2
- *OPT 3
- *OPT 4,n specify boot option
- *OPT 5
- *OPT 6,n use internal device drivers for drive n (HADFS)
- *OPT 7,n use external device drivers for drive n (HADFS)
- *OPT 40,d - some systems implement *OPT40,d to select double-stepping on drive d.
- *OPT 80,d - some systems implement *OPT80,d to select single-stepping on drive d.
- TubeHost implements FSC &FF so that a client filing system can indicate a Shift-Break or a Tube Client Startup has occured.
Some systems search the only current directory with *RUN and search the current directory and the current library library with */name and *name.
