Difference between revisions of "OSBYTE &B9"

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[[Category:OSBYTE]]
 
[[Category:OSBYTE]]
OSBYTE &B9 (185) - Read/Write MOS copy of palette register/ROM polling semaphore
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OSBYTE &B9 (185) - Read MOS copy of palette register
  
     On the BBC, B+ and Master, this contains the MOS's copy of the palette
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     (Electron OS)
     register in the video ULA.
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     Read/Write ROM polling semaphore
   
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     This is the value adjusted by *FX22 and *FX23
    On the Electron there is no video ULA, and this location contains the ROM
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    polling semaphore. When the semaphore is non-zero the 100Hz ROM service
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     call &15 is sent to ROMs. The semaphore is normally accessed with *FX23
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    to increment it and *FX24 to decrement it.
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==See Also==
 
==See Also==
* [[OSBYTE &16|OSBYTE &16]] - Increment ROM polling semaphore
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* http://mdfs.net/Docs/Comp/BBC/OsbyteA6
* [[OSBYTE &17|OSBYTE &17]] - Decrement ROM polling semaphore
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* [[OSBYTE &B3|OSBYTE &B3]] - Master ROM polling semaphore location
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* [[Paged ROM service calls]]
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[[User:Jgharston|Jgharston]] 22:30, 26 May 2009 (UTC)
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[[User:Jgharston|Jgharston]] 22:34, 26 May 2009 (UTC)

Latest revision as of 19:12, 8 March 2015

OSBYTE &B9 (185) - Read MOS copy of palette register

   (Electron OS)
   Read/Write ROM polling semaphore
   This is the value adjusted by *FX22 and *FX23

See Also

Jgharston 22:34, 26 May 2009 (UTC)