DOS system function call table (INT 21H)

DOS function Call

Author: Source: Internet

AH Function Calling parameters return parameters 00 program termination (same as int 20H) Cs= Program Segment Prefix 　 01 Keyboard input and Echo 　 Al= input Characters 02 Display output Dl= Output characters 　 03 Asynchronous communication input 　 al= input data 04 Asynchronous communication output Dl= output data 　 05 Printer output Dl= Output characters 　 06 Direct console I/O DL=FF (Input) dl= character (output) Al= input Characters 07 Keyboard input (no echo)