Difference between revisions of "OSBYTE &B3"

From BeebWiki
Jump to: navigation, search
m (1 revision)
 
(One intermediate revision by one user not shown)
Line 1: Line 1:
 
[[Category:OSBYTE]]
 
[[Category:OSBYTE]]
OSBYTE &B3 (179) - Read/Write primary OSHWM/ROM polling semaphore
+
OSBYTE &B3 (179) - Read/Write primary OSHWM
  
     On the BBC, B+ and Electron, this contains the page number of OSHWM
+
     This value contains the page number of OSHWM ignoring any font implosions
    ignoring any font implosions and explosions.
+
     and explosions
      
+
    On the Master onwards, the font is always exploded, and this location
+
    contains the ROM polling semaphore. When the semaphore is non-zero the
+
    100Hz ROM service call &15 is sent to ROMs. The semaphore is normally
+
    accessed with *FX23 to increment it and *FX24 to decrement it.
+
  
 
==See Also==
 
==See Also==
* [[OSBYTE &16|OSBYTE &16]] - Increment ROM polling semaphore
+
* http://mdfs.net/Docs/Comp/BBC/OsbyteA6
* [[OSBYTE &17|OSBYTE &17]] - Decrement ROM polling semaphore
+
* [[OSBYTE &B9|OSBYTE &B9]] - Electron ROM polling semaphore location
+
* [[Paged ROM service calls]]
+
  
 
[[User:Jgharston|Jgharston]] 22:30, 26 May 2009 (UTC)
 
[[User:Jgharston|Jgharston]] 22:30, 26 May 2009 (UTC)

Latest revision as of 19:12, 8 March 2015

OSBYTE &B3 (179) - Read/Write primary OSHWM

   This value contains the page number of OSHWM ignoring any font implosions
   and explosions

See Also

Jgharston 22:30, 26 May 2009 (UTC)