58484



     PAD" mode. It can be reached from BASIC by typing "BYE",
     "B." or by powering up with no peripherals or cartridges.
     Nothing you write to the screen in blackboard mode is acted
     upon by the computer. You can enter this mode to protect your
     programs temporarily from prying and curious fingers.

     All of the screen editing commands continue to work in
     blackboard mode. You can enter blackboard mode from any
     graphics mode with a text window; the display screen will remain
     intact on the screen while the text window will be in blackboard
     mode. Pressing RESET will, of course, return the entire screen to
     GR.0. You can also enter blackboard mode from a program, but
     cannot get out of it in BASIC once you are in it.

     If you entered blackboard mode from BASIC, you can return to it
     by pressing RESET. Any BASIC program will still be there. So
     will any RS-232 or DOS handlers previously booted. Initialized to
     61987 ($F223).

58484          E474           WARMSV
     Warmstart entry point (RESET button vector). Initializes the OS
     RAM region. The RESET key produces an NMI interrupt and a
     chip reset (see below). Jump to here on an NMI caused by
     pressing the RESET key. Initialized to 61723 ($F11B).

58487          E477           COLDSV
     Coldstart (powerup) entry point. Initializes the OS and user RAM
     regions; wipes out any program in memory. Initialized to 61733
     ($F125).

58490          E47A           RBLOKV
     Cassette read block routine entry, OS use only.

58493          E47D           CSOPIV
     Cassette OPEN for input vector, OS use only.

58496          E480           VCTABL
     RAM vector initial value table.

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The following are the addresses for the handler routines:

58534-59092    E4A6-E6D4      CIOORG
Addresses for the Central Input/Output routines (CIO):

58534 ($E4A6) CIOINT is the CIO initialization routine called by
the monitor on powerup.

58577 ($E4D1); move the user IOCB to the ZIOCB.

58596 ($E4E4); check for a valid command.

58633 ($E509); OPEN command routines.