Online 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
[helppc.bosbyte.nl] int 21,6