Difference between revisions of "OSBYTE &00"
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[[Category:OSBYTE]] | [[Category:OSBYTE]] | ||
===OSBYTE &00 (0) - Identify Host/Operating System=== | ===OSBYTE &00 (0) - Identify Host/Operating System=== | ||
| + | <div class="mw-widebody"> | ||
On entry, X=0 - Generate error number 247 giving host and OS type | On entry, X=0 - Generate error number 247 giving host and OS type | ||
X<>0 - Return host/OS in X | X<>0 - Return host/OS in X | ||
| − | + | ||
On exit, X=host/OS type: | On exit, X=host/OS type: | ||
:d.dir.file/ext dir/file.ext :d.dir.file/ext d:file.ext | :d.dir.file/ext dir/file.ext :d.dir.file/ext d:file.ext | ||
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32 IBM PC-type system (DOS, Windows, etc.) | 32 IBM PC-type system (DOS, Windows, etc.) | ||
39 6809/6309 system | 39 6809/6309 system | ||
| + | </div> | ||
==Implementations== | ==Implementations== | ||
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second processor will always be told what the I/O host is regardless of | second processor will always be told what the I/O host is regardless of | ||
what the host is and what the second processor is. | what the host is and what the second processor is. | ||
| + | |||
| + | 80x86 BBC BASIC running on DOS and Windows returns 32 as a side effect | ||
| + | of reading the character under the cursor. Properly written code that | ||
| + | calls OSBYTE 0 will know to do so when there is a space under the cursor. | ||
| + | Normally this just means calling OSBYTE 0 at program startup before | ||
| + | outputting anything. | ||
==Platform capabilities== | ==Platform capabilities== | ||
Revision as of 03:01, 17 January 2021
Contents
OSBYTE &00 (0) - Identify Host/Operating System
On entry, X=0 - Generate error number 247 giving host and OS type
X<>0 - Return host/OS in X
On exit, X=host/OS type:
:d.dir.file/ext dir/file.ext :d.dir.file/ext d:file.ext
0 Electron/Communicator 8 UNIX-type system
1 BBC 9 6809/6309 system 17 6809/6309 system
2 BBC B+ 10 MacOS X
3 Master 128
4 Master ET 28 Commodore 64/128
5 Master Compact 29 Texas Instruments calculator
6 Arthur or RISC OS 30 Amstrad CPC
7 Springboard 31 Sinclair ZX Spectrum
d:\dir\file.ext
32 IBM PC-type system (DOS, Windows, etc.)
39 6809/6309 system
Implementations
Early documentation refers to OSBYTE 0 as returning the OS version. As more systems were developed, it became more correct to refer to it returning a value indicating the host. For example, code running on a second processor will always be told what the I/O host is regardless of what the host is and what the second processor is.
80x86 BBC BASIC running on DOS and Windows returns 32 as a side effect of reading the character under the cursor. Properly written code that calls OSBYTE 0 will know to do so when there is a space under the cursor. Normally this just means calling OSBYTE 0 at program startup before outputting anything.
Platform capabilities
Over time the OSBYTE 0 return value has evolved to become a bitmap representing the capabilities of the host system, primarily of the file system structure.
-
%000x0xxxFilenames are directory.filename/extension, eg BBC, RISC OS -
%000x1xxxFilenames are directory/filename.extension, eg Unix, CP/M -
%nnnxxxxxFilenames are directory\filename.extension, eg DOS, Windows
This can also be represented as:
-
%000x0xxxDirectory seperator is'.' -
%000x1xxxDirectory seperator is'/' -
%nnnxxxxxDirectory seperator is'\'
-
%000x0xxxExtension seperator is'/' -
%nnnxnxxxExtension seperator is'.'
This allow programs to use code similar to the following:
A%=0:X%=1:os%=((USR&FFF4)AND&FF00)DIV256 d$=".":s$="/":IF(os%AND-24):d$="/":s$=".":IF(os%AND-32):d$="\" filename$=dir$+d$+name$+s$+ext$
See also
Jgharston 22:41, 6 September 2007 (BST) Jgharston (talk) 06:35, 12 April 2020 (CEST)
