🚀 go-pugleaf

>>>>> On 26 Oct 1992 00:13:25 -0600, cbusch@ub.d.umn.edu (Mmmm...) said:
Chris> I am trying to write a keyboard handler that will allow me 
Chris> to know if any two keys are being pressed simultaneously.
Chris> What are the ports that i should read?  And how do i interpret
Chris> the this?

Look how it is done in BIOS. In short: must service interrupt 09h
(IRQ1). On XT: read scan code from port 60h, read port 61h, write
value read ORed with 80h, write original value, write 20h to port
20h (end-of-interrupt), IRET. On AT: should send Keyboard Disable
command to port 64h (before sending wait until 8042 input register
is empty), read scan code from port 60h, if it says "transmission
parity error" can request retransmission, otherwise can send
Keyboard Enable (unless want other program to read the scan code
and finish interrupt service), write 20h to port 20h, IRET.
The scan code shows which key was pressed or released (or is
repeating), can also show some special information from Keyboard.
Codes <80h means key was pressed, same codes+80h - released.
Look your computer Technical Reference for details.