Difference between revisions of "OSBYTE &00"

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[[Category:OSBYTE]]
 
[[Category:OSBYTE]]
===OSBYTE &00 (0) - Identify Host/Operating System===
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{{PageTitle|OSBYTE &00 (0) - Identify Host/Operating System}}
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<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
 
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  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
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  0 Electron/Communicator  8 UNIX-type system                        24 CP/M-type system
  0 Electron           8 UNIX-type system
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  1 BBC                   9 6809/6309 system    17 6809/6309 system
  1 BBC                 9 6809/6309 system    17 6809/6309 system
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  2 BBC B+               10 Apple/Mac/etc
  2 BBC B+             10 Atom/System          18 Atom/System
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  3 Master 128
  3 Master 128
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  4 Master ET                                                        28 Commodore 64/128
  4 Master ET                                                        28 Commodore 64/128
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  5 Master Compact                                                    29 Texas Instruments calculator
  5 Master Compact                                                    29 Texas Instruments calculator
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  6 Arthur or RISC OS                                                30 Amstrad CPC
  6 Arthur or RISC OS                                                30 Amstrad CPC
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  7 Springboard                                                      31 Sinclair ZX Spectrum
  7 Springboard                                                      31 Sinclair ZX Spectrum
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  Filesystem used:
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    :d.dir.file/ext          dir/file.ext            :d.dir.file/ext    d:file.ext
 
   
 
   
    d:\dir\file.ext
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On exit,  X=host/OS type:
32 IBM PC-type system (DOS, Windows, etc.)
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  32 (&20) IBM PC-type system (DOS, Windows, etc.)
39 6809/6309 system
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  43 (&2B) DEC DOS11/RSX11/RSTS/RT11 (DOS-style filesystem)
 
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  57 (&39) 6809/6309 system with DOS-style filesystem
The Atom/System entries are tentative values for an Atom or System with a
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  Filesystem used:
BBC API and OSBYTE entry.
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    d:\dir\file.ext
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</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.
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 +
80x86 BBC BASIC running on DOS and Windows returns 32 as a side effect
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of reading the character under the cursor. Properly written code that
 +
calls OSBYTE 0 will know to do so in a manner that ensures this occurs.
 +
Normally this just means calling OSBYTE 0 at program startup before
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outputting anything.
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 +
When writing a host, OSBYTE 0,0 should generate an error with the text
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in the form:
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* "MOS NAME a.bc"
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* or "MOS NAME a.bc (dd Mmm yyyy)"
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* or "MOS NAME a.bc (dd Mmm yyyy) additional info"
  
 
==Platform capabilities==
 
==Platform capabilities==
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* [[Multiplatform programming]]
 
* [[Multiplatform programming]]
  
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----
 
[[User:Jgharston|Jgharston]] 22:41, 6 September 2007 (BST)
 
[[User:Jgharston|Jgharston]] 22:41, 6 September 2007 (BST)
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[[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 06:35, 12 April 2020 (CEST)

Latest revision as of 04:12, 10 July 2021

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:
  0 Electron/Communicator  8 UNIX-type system                         24 CP/M-type system
  1 BBC                    9 6809/6309 system     17 6809/6309 system
  2 BBC B+                10 Apple/Mac/etc
  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
 Filesystem used:
    :d.dir.file/ext          dir/file.ext            :d.dir.file/ext     d:file.ext

On exit,  X=host/OS type:
 32 (&20) IBM PC-type system (DOS, Windows, etc.)
 43 (&2B) DEC DOS11/RSX11/RSTS/RT11 (DOS-style filesystem)
 57 (&39) 6809/6309 system with DOS-style filesystem
 Filesystem used:
    d:\dir\file.ext

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 in a manner that ensures this occurs. Normally this just means calling OSBYTE 0 at program startup before outputting anything.

When writing a host, OSBYTE 0,0 should generate an error with the text in the form:

  • "MOS NAME a.bc"
  • or "MOS NAME a.bc (dd Mmm yyyy)"
  • or "MOS NAME a.bc (dd Mmm yyyy) additional info"

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.

  • %000x0xxx Filenames are directory.filename/extension, eg BBC, RISC OS
  • %000x1xxx Filenames are directory/filename.extension, eg Unix, CP/M
  • %nnnxxxxx Filenames are directory\filename.extension, eg DOS, Windows

This can also be represented as:

  • %000x0xxx Directory seperator is '.'
  • %000x1xxx Directory seperator is '/'
  • %nnnxxxxx Directory seperator is '\'
  • %000x0xxx Extension seperator is '/'
  • %nnnxnxxx Extension 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)