Assembler

[SpectruM]

The Keyboard is the primary method for grabbing input from users. When
a key is hit, an interrupt is generated ( INT 9 ). The latter reads the
Scan Code generated by the keyboard ( A Scan Code is one or more bytes
generated by the keyboard as a result of a key pressed or released - Each
key on the Keyboard generates a unique Scan Code ). INT 9H also provides
a mechanism for Scan Code Translation. INT 9H calls INT 15/4F with the
Scan Code of the key pressed before processing the Scan Code. The INT 15/4F
handler may instruct INT 9H to either ignore the key pressed or translate
the Scan Code to another value.
A user-defined INT 15/4F handler can therefore be used to *disable* a
particular key and/or to change the Scan Code it effectively generates.
The following example illustrates Scan Code translation. The ESC's Scan Code
is translated to that of an 'A'.

The Handler also instruct INT 9H to ignore the DEL Key. Therefore the
user is unable to reboot the machine using CRTL-ALT-DEL while the Handler
is active