How do i read the buttons on the AVR-MT ?

How do i read the buttons on the AVR-MT ? :?:

Best Regards

Terje.

www.olimex.com/dev/avr-mt.html have link to assembly code

Best regards

Tsvetan

Yes, i have already the avr_mt.asm.

This file contains only Display and Buzzer code.

Best Regards

Terje Sjomark.