OSWORD &FA

OSWORD &FA (250) - Data transfer over Tube (80x86 Tube OS)

 On entry:
   XY?0     =&0D or &0E (send block length)
   XY?1     =&10 (receive block length)
   XY!2     =I/O processor address
   XY+6..7  =80x86 offset address
   XY+8..9  =80x86 segment address
   XY+10..11=data length
   XY?12    =function
   XY?13    =memory access control if XY?0=&0E.

The functions are the same as the Tube values:

• 0 - write to I/O as single bytes
• 1 - read from I/O as single bytes
• 2 - write to I/O as byte pairs
• 3 - read from I/O as byte pairs
• 6 - write to I/O as groups of 256 bytes
• 7 - read from I/O as groups of 256 bytes

If the memory access control byte is not used the I/O address at XY!2 accesses the main I/O memory and whichever ROM happens to be paged in when the call is made - usually the current language. If the memory access control byte is used, its format is:

• b0-b3=ROM number
• b4 =0 use specified ROM, b4=1 use current ROM
• b5 =0 use main memory, b5=1 use screen memory
• b6 =1 ignore b5 and use shadow memory
• b7 unused.

See Also

• OSWORD &05
• OSWORD &06
• OSWORD &FF
• http://mdfs.net/Docs/Comp/BBC/Oswords

Jgharston 14:26, 26 May 2009 (UTC) Jgharston (talk) 00:05, 31 January 2016 (UTC)