Interrupt 16H — Keyboard Input/Output - Zenith Z-100 Reference Manual

Page 5.2
Keyboard
Interrupt 16H — Keyboard
Input/Output
Three operation codes are used with this interrupt to determine the function to
be performed.
0 — Get a character from the keyboard
1 — Determine if a key code is waiting in the keyboard's buffer
2 — Return the keyboard's shift status
To use this interrupt, load the desired operation code in register AH and then
execute an INT 16H instruction. Table 5.1 describes the results for each operation
code.