HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens

                        INT 21,6 - Direct Console I/O

       AH = 06
       DL = (0-FE) character to output
          = FF if console input request

       on return:
       AL = input character if console input request (DL=FF)
       ZF = 0  if console request character available (in AL)
          = 1  if no character is ready, and function request
            was console input

       - reads from or writes to the console device depending on
         the value of DL
       - cannot output character FF  (DL=FF indicates read function)
       - for console read, no echo is produced
       - returns 0 for extended keystroke, then function must be
         called again to return scan code
       - ignores Ctrl-Break and Ctrl-PrtSc

Esc or Alt-X to exit int 21,6 Home/PgUp/PgDn/End ←↑↓→
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