Difference between revisions of "OSWORD &FF"

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(Added address of VDU workspace RAM.)
m (.)
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[[Category:OSWORD]][[Category:Second Processors]]__NOTOC__
 
[[Category:OSWORD]][[Category:Second Processors]]__NOTOC__
==Z80 Data transfer over Tube (Z80 Tube OS)==
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==OSWORD &FF (255) - Z80 Data transfer over Tube (Z80 Tube OS)==
  
On entry:
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  On entry:
  XY?0    =&0D (send block length)
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    XY?0    =&0D (send block length)
  XY?1    =&01 (receive block length)
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    XY?1    =&01 (receive block length)
  XY!2    =I/O address
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    XY!2    =I/O address
  XY!6    =Z80 address
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    XY!6    =Z80 address
  XY+10..11=data length
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    XY+10..11=data length
  XY?12    =command, 0=write to I/O, 1=read from I/O.
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    XY?12    =command, 0=write to I/O, 1=read from I/O.
  The control block is not updated on return.
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    The control block is not updated on return.
  
The I/O address at XY!2 accesses the main I/O memory and whichever ROM happens to
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The I/O address at XY!2 accesses the main I/O memory and whichever ROM
be paged in when the call is made - usually the current language. An updated version
+
happens to be paged in when the call is made - usually the current language.
of the OSWORD &FF code uses the full I/O addressing range to access sideways ROMs
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An updated version of the OSWORD &FF code uses the full I/O addressing range
and both banks of screen memory<ref name="code">[http://mdfs.net/Software/Tube/Z80/ Osword &FF code]</ref>:
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to access sideways ROMs and both banks of screen
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memory<ref name="code">[http://mdfs.net/Software/Tube/Z80/ Osword &FF code]</ref>:
  
 
   &FFFFxxxx - Main memory
 
   &FFFFxxxx - Main memory
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   &FF8xxxxx - VDU workspace RAM
 
   &FF8xxxxx - VDU workspace RAM
  
The OSWORD &FF code is available as a *runnable file that can be used with any second processor<ref name="code">[http://mdfs.net/Software/Tube/Z80/ Osword &FF code]</ref>.
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The OSWORD &FF code is available as a *runnable file that can be used with
 +
any second processor<ref name="code">[http://mdfs.net/Software/Tube/Z80/ Osword &FF code]</ref>.
  
 
==DOS fast screen control (80x86 DOS)==
 
==DOS fast screen control (80x86 DOS)==
  
On entry:
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  On entry:
  XY?0    =&00 (send block length)
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    XY?0    =&00 (send block length)
  XY?1    =&00 (receive block length)
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    XY?1    =&00 (receive block length)
  
 
The control block is ignored, so for speed, set XY?0=0 and XY?1=0.
 
The control block is ignored, so for speed, set XY?0=0 and XY?1=0.
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==See Also==
 
==See Also==
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* [[OSWORD &05]]
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* [[OSWORD &06]]
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* [[OSWORD &FA]]
 
* [http://mdfs.net/Docs/Comp/BBC/Oswords OSWORDs list at mdfs.net]
 
* [http://mdfs.net/Docs/Comp/BBC/Oswords OSWORDs list at mdfs.net]
 
* [http://mdfs.net/Software/Tube/Z80/ OSWORD &FF source code]
 
* [http://mdfs.net/Software/Tube/Z80/ OSWORD &FF source code]
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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)

Revision as of 01:06, 31 January 2016

OSWORD &FF (255) - Z80 Data transfer over Tube (Z80 Tube OS)

 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
   XY?12    =command, 0=write to I/O, 1=read from I/O.
   The control block is not updated on return.

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].

DOS fast screen control (80x86 DOS)

 On entry:
   XY?0     =&00 (send block length)
   XY?1     =&00 (receive block length)

The control block is ignored, so for speed, set XY?0=0 and XY?1=0.

Commands are sent from the 80x86 via Tube register 2. First, 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.

After an address has been sent, a command loop is entered. The command is sent through Tube register 2. Commands are:

  • &FF - single byte read through Tube register 1 fills the following eight bytes of screen memory.
  • &00 - eight bytes read though Tube register 1 fill following eight bytes of screen memory.
  • Other - loop back to wait for address or termination.

See Also

References

Jgharston 14:30, 26 May 2009 (UTC) Jgharston (talk) 00:06, 31 January 2016 (UTC)