OSBYTE &16

OSBYTE &16 (22) - Increment Polling Semaphore

   This call increments a counter, which if non zero will cause 100 service
   calls (type &15) per second to be sent the paged ROMs. This allows a way 
   for ROMs to poll hardware which doesn't offer interrupts.
   
   On exit:
     X=preserved - Polling semaphore exists
     X=&FF       - Polling semaphore not implemented

See Also

• OSBYTE &17 - Decrement Polling Semaphore
• http://mdfs.net/Docs/Comp/BBC/Osbyte00

Jgharston 21:31, 26 May 2009 (UTC) Jgharston (talk) 02:03, 6 November 2020 (CET)