Difference between revisions of "OSWORD &FF"

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m (Slight formatting changes.)
(Rewrote 80x86 transaction description.)
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[[Category:OSWORD]][[Category:Second Processors]]__NOTOC__
 
[[Category:OSWORD]][[Category:Second Processors]]__NOTOC__
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{{PageTitle|OSWORD &FF (255) - Data transfer over Tube}}
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{{PageTitle|OSWORD &FF (255) Data transfer over Tube}}
 
==Data transfer over Tube==
 
==Data transfer over Tube==
 
This OSWORD call is installed by the Z80 Tube client.
 
This OSWORD call is installed by the Z80 Tube client.
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     XY?12    =command, 0=write to I/O, 1=read from I/O
 
     XY?12    =command, 0=write to I/O, 1=read from I/O
 
     The control block is not updated on return.
 
     The control block is not updated on return.
 +
 +
The commands are the same as the Tube values:
 +
* 0 - write single bytes to I/O
 +
* 1 - read single bytes from I/O
  
 
The I/O address at XY!2 accesses the main I/O memory and whichever ROM
 
The I/O address at XY!2 accesses the main I/O memory and whichever ROM
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any second processor<ref name="code">[http://mdfs.net/Software/Tube/Z80/ Osword &FF code]</ref>.
 
any second processor<ref name="code">[http://mdfs.net/Software/Tube/Z80/ Osword &FF code]</ref>.
  
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==DOS fast screen control==
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The code installed by the Z80 Tube client v1.36 and later also implements
 +
2-byte data transfers, the data length must be even:
 +
* 0 - write single bytes to I/O
 +
* 1 - read single bytes from I/O
 +
* 2 - write byte pairs to I/O
 +
* 3 - read byte pairs from I/O
 +
 
 +
==DOS fast screen control (80x86 DOS)==
 
This OSWORD call is installed by the 80x86 DOS BIOS.
 
This OSWORD call is installed by the 80x86 DOS BIOS.
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  On entry:
 
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    XY?0    =&00 (send block length)
 
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    XY?1    =&00 (receive block length)
 
−
 
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The control block is ignored, so for speed, set XY?0=0 and XY?1=0.
 
−
 
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Commands are sent from the 80x86 via Tube register 2. First, the address is sent,
 
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high byte then low byte. This address is updated for the data sent and wraps round
 
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from &7FFF to &4000. If the high byte is &00, no low byte is sent, and the routine
 
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finishes.
 
−
 
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After an address has been sent, a command loop is entered. The command is sent
 
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through Tube register 2. Commands are:
 
  
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* &FF - single byte read through Tube register 1 fills the following eight bytes of screen memory.
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Commands are sent from the 80x86 via Tube Register 2 within the OSWORD protocol,
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* &00 - eight bytes read though Tube register 1 fill following eight bytes of screen memory.
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so cannot be called through the normal OSWORD mechanism. The transaction must be
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* Other - loop back to wait for address or termination.
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done manually by the client by sending through Tube Register 2:
 +
    &08 : Start OSWORD transaction
 +
    &FF : OSWORD call &FF
 +
    &00 : TxLen=0
 +
 
 +
  Then address/command pairs are sent. The address is sent, high byte then low byte. This
 +
  address is updated for the data sent and wraps round from &7FFF to &4000. If the high
 +
  byte is &00, no low byte is sent, and the routine finishes. Commands are:
 +
    &FF : Read a single byte from through Tube register 1 to fill the following eight
 +
          bytes of screen memory.
 +
    &00 : Read eight bytes from Tube register 1 fill the following eight bytes of
 +
          screen memory.
 +
  Other: Loop back to wait for address or termination.
 +
 
 +
  Then finish with:
 +
    &00 : RxLen=0, terminate the OSWORD call
  
 
==See also==
 
==See also==
 
* [[OSWORD &05]]
 
* [[OSWORD &05]]
 
* [[OSWORD &06]]
 
* [[OSWORD &06]]
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* [[OSWORD &72]]
 
* [[OSWORD &FA]]
 
* [[OSWORD &FA]]
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* [[OSWORD &FB]]
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* [[OSWORD &FC]]
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* [[OSWORD &FD]]
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* [[OSWORD &FE]]
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* [http://mdfs.net/Software/Tube/Utils/ OSWORD &FE source code]
 
* [http://mdfs.net/Docs/Comp/BBC/Oswords OSWORDs list at mdfs.net]
 
* [http://mdfs.net/Docs/Comp/BBC/Oswords OSWORDs list at mdfs.net]
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* [http://mdfs.net/Software/Tube/Utils/ OSWORD &FF source code]
 
  
 
==References==
 
==References==
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[[User:Jgharston|Jgharston]] 14:30, 26 May 2009 (UTC)
 
[[User:Jgharston|Jgharston]] 14:30, 26 May 2009 (UTC)
−
[[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 00:06, 31 January 2016 (UTC)
+
[[User:Jgharston|Jgharston]] 00:06, 31 January 2016 (UTC)
 +
[[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 11:05, 17 December 2024 (CET)

Revision as of 11:05, 17 December 2024

OSWORD &FF (255) Data transfer over Tube

Data transfer over Tube

This OSWORD call is installed by the Z80 Tube client. 

 On entry:
   XY?0     =&0D (send block length)
   XY?1     =&01 (receive block length)
   XY!2     =I/O address
   XY!6     =Z80 address
   XY+10..11=data length, &0000=nothing to transfer
   XY?12    =command, 0=write to I/O, 1=read from I/O
   The control block is not updated on return.

The commands are the same as the Tube values:

  • 0 - write single bytes to I/O
  • 1 - read single bytes from I/O

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. An updated version of the OSWORD &FF code uses the full I/O addressing range to access sideways ROMs and both banks of screen memory[1]: 

 &FFFFxxxx - Main memory
 &FFFExxxx - Currently displayed screen memory
 &FFFDxxxx - Shadow screen memory
 &FFxRxxxx - Sideways ROM/RAM R
 &FF8xxxxx - VDU workspace RAM

The OSWORD &FF code is available as a *runnable file that can be used with any second processor[1].

The code installed by the Z80 Tube client v1.36 and later also implements 2-byte data transfers, the data length must be even:

  • 0 - write single bytes to I/O
  • 1 - read single bytes from I/O
  • 2 - write byte pairs to I/O
  • 3 - read byte pairs from I/O

DOS fast screen control (80x86 DOS)

This OSWORD call is installed by the 80x86 DOS BIOS.

Commands are sent from the 80x86 via Tube Register 2 within the OSWORD protocol, so cannot be called through the normal OSWORD mechanism. The transaction must be done manually by the client by sending through Tube Register 2: 

   &08 : Start OSWORD transaction
   &FF : OSWORD call &FF
   &00 : TxLen=0
 
 Then address/command pairs are sent. The address is sent, high byte then low byte. This
 address is updated for the data sent and wraps round from &7FFF to &4000. If the high
 byte is &00, no low byte is sent, and the routine finishes. Commands are:
   &FF : Read a single byte from through Tube register 1 to fill the following eight
         bytes of screen memory.
   &00 : Read eight bytes from Tube register 1 fill the following eight bytes of
         screen memory.
  Other: Loop back to wait for address or termination.
 
 Then finish with:
   &00 : RxLen=0, terminate the OSWORD call

See also

References

  1. ↑ 1.0 1.1 Osword &FF code

Jgharston 14:30, 26 May 2009 (UTC) Jgharston 00:06, 31 January 2016 (UTC) Jgharston (talk) 11:05, 17 December 2024 (CET)

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