700



     lines minus one that were deleted from the top of the screen. This
     moves the entire screen up one physical line for each line
     scrolled off the top. Since a logical line has three physical lines,
     SCRFLG ranges from zero to two.

     Scrolling the text window is the equivalent to scrolling an entire
     GR.0 screen. An additional 20-line equivalent of bytes (800) is
     scrolled upwards in the memory below the text window address.
     This can play havoc with any data such as P/M graphics you have
     stored above RAMTOP

700            2BC            HOLD4
     Temporary register used in the DRAW command only; used to
     save and restore the value in ATACHR (location 763; $2FB)
     during the FILL process.

701            2BD            HOLD5
     Same as the above register.

702            2BE            SHFLOK
     Flag for the shift and control keys. It returns zero for lowercase
     letters, 64 ($40) for all uppercase (called caps lock: uppercase is
     required for BASIC statements and is also the default mode on
     powerup). SHFLOK will set characters to all caps during your
     program if 64 is POKEd here. Returns the value 128 ($80;
     control-lock) when the CTRL key is pressed. Forced control-lock
     will cause all keys to output their control-code functions or
     graphics figures. Other values POKEd here may cause the
     system to crash. You can use this location with 694 ($2B6) above
     to convert all keyboard entries to uppercase, normal display by:

     10   OPEN #2,4,0,"K:"
     20   GET #2,A
     30   GOSUB 1000
     40   PRINT CHR$(A);: GOTO 20
     .
     .
     .
     1000 IF A = 155 THEN 1030: REM RETURN
           KEY
     1010 IF A > = 128 THEN A = A - 128: R
          EM RESTORE TO NORMAL DISPLAY
     1020 IF PEEK (702) = 0 AND A > 96 THEN
           A = A - 32: REM LOWERCASE TO UP
          PER
     1030 POKE 702,64: POKE 694,0
     1040 RETURN