Marking of Assignment 4

Question 1 was marked out of 10. Marks were assigned as follows:

• 1 for handing in a solution with your name and student number
• 1 for printing your name and student number on display
• 1 for saving/restoring previous interrupt vectors
• 1 for disabling interrupts while changing interrupt vectors
• 1 for waiting until count is set to 2
• 1 for returning control back to DOS (INT 20H or RET)
• 1 for saving/restoring working registers in ISR
• 1 for only incrementing count on scan code 82H
• 1 for issuing EOI to PIC
• 1 for returning with IRET (not RET) instruction