Difference between revisions of "OSWORD"
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other calls return data in the control block. | other calls return data in the control block. | ||
| − | OSWORD calls with numbers greater than &7F | + | OSWORD calls with numbers &15-&7F must only have a maximum of 16 bytes |
| − | parameters to send in the first byte of the parameter block, and the number | + | in the control block. OSWORD calls with numbers greater than &7F must |
| − | of parameters to receive in the second byte of the parameter block, | + | contain the number of parameters to send in the first byte of the |
| − | inclusive of the first two bytes. | + | parameter block, and the number of parameters to receive in the second |
| + | byte of the parameter block, inclusive of the first two bytes. There are | ||
| + | some calls that break this and will not work in all cases. | ||
| − | OSWORD calls with numbers &E0 to &FF are "available for use by the user".<ref | + | OSWORD calls with numbers &E0 to &FF are "available for use by the user" |
| − | name="sadek">R.I.M. Sadek (1986), | + | and are passed directly to [[USERV]] on the 6502 I/O processor.<ref |
| − | ''The complete disc manual for the BBC Microcomputer'', Macmillan Education | + | name="sadek">R.I.M. Sadek (1986), ''The complete disc manual for the BBC |
| − | Ltd. p.107.</ref> | + | Microcomputer'', Macmillan Education Ltd. p.107.</ref> |
| − | + | <ref name="appnote-004">Acorn Computers (June 1992), | |
| − | 1992), ''Application note 004: Tube application note'', p.5.</ref> | + | ''Application note 004: Tube application note'', p.5.</ref> |
==Calling from BBC BASIC== | ==Calling from BBC BASIC== | ||
Revision as of 01:04, 26 April 2020
Miscellaneous actions with a control block
Specification
| 6502 | Z80 | 6809 | PDP11 | 80x86 | 32016 | ARM | On entry: | On exit: |
| A | A | A | R0 | AL | R1 | R0 | = function code | undefined |
| XY | HL | X | R1 | BX | R2 | R1 | =>control block | undefined, control block updated |
| Control block for calls>&7F | ||||||||
| &00 | Length of sent control block | |||||||
| &01 | Length of received control block | |||||||
| &02... | Any other parameters | |||||||
OSWORD &00 is the only call that is allowed to return data in registers. All other calls return data in the control block.
OSWORD calls with numbers &15-&7F must only have a maximum of 16 bytes in the control block. OSWORD calls with numbers greater than &7F must contain the number of parameters to send in the first byte of the parameter block, and the number of parameters to receive in the second byte of the parameter block, inclusive of the first two bytes. There are some calls that break this and will not work in all cases.
OSWORD calls with numbers &E0 to &FF are "available for use by the user" and are passed directly to USERV on the 6502 I/O processor.[1] [2]
Calling from BBC BASIC
-
INPUTcalls OSWORD &00 -
=TIMEcalls OSWORD &01 -
TIME=calls OSWORD &02 -
SOUNDcalls OSWORD &07 -
ENVELOPEcalls OSWORD &08 -
=POINTcalls OSWORD &09 -
=TIME$calls OSWORD &0E -
TIME$=calls OSWORD &0F
Entry points
- BBC BASIC Entry Address: &FFF1
- 6502 Entry Address: &FFF1, vectors via &020C
- Z80 Entry Address: &FFF1, vectors via &FFF2
- 6809 Entry Address: &FFF1, vectors via &FFF2
- 80x86 Entry Address: INT &4A, vectors via &0000:0128
- 32000 Entry Address: SVC &07
- PDP-11 Entry Address: EMT 3, vector &03
- ARM Entry Address: SWI &07 "OS_Word", vector &07
See Also
References
Jgharston 17:03, 6 November 2009 (UTC)
