I want to implement a Snake game, and I have several questions which I've stuck into this one thread:

1. Remapping keyboard handler.

When a key is pressed, INT 9 goes off. So, how can I install my own keyboard handler to INT 9? I want to be able to capture events.

2. Keeping the snake moving using time interval

I was thinking about how I'd keep the snake moving at a pace, and I thought of using time intervals. How does one implement a timer so that certain actions are carried out within the set intervals?

Apologies if I my questions aren't clear

Theres a good example in this asm game
http://www.programmersheaven.com/download/1006/Download.aspx

the timer should not update the position of the snake.
the timer delta should just be used as the T variable in the Snake movement equation. exactlly as a keyboard interrupt routine should not do anything related to an application, but should just reports the hw state to be used later by your application.


you can also set a call-back mecanism inside your custom interrupts, but they should not be big, otherwise, you will slow down your computer.


to install a interrupt handler, just disable interruptions, set the new adress in the interrupt vector, and reenable the interrupts.

an interrupt routine should always end by a EndOfInterrupt signal before the iret.
special peripherals like the keyboard need also a bunch of tests and ports reads/writes to tell it's ok to receive the next event.