INT 15H 5306H: CPU Busy

 Expects: AX    5306H
 Returns: CY    clear (always succeeds)
    Info: This function informs the BIOS that processing should continue at
          full speed.

          You may access this service via INT 15H or by using the APM entry
          address obtained via INT 15H 5302H or INT 15H 5303H (protected
          mode connect).

          The BIOS will usually be able to tell when it should switch back
          to full-speed operation, but it is possible that an interrupt has
          been hooked which keeps the BIOS uninformed.  In that case, you
          may wish to use this call once or twice per second to tell the
          BIOS to keep the CPU awake.

See Also: APM API