Timer Interrupt

Hi friends,



I have a query here.

Recently, I am supposed to program a real time clock to be displayed on

the screen.

The program will accept users' input of hours, minutes, and seconds.

then i will increment from there and so implementing a displayed clock.


the problem now is that my clock runs differently on different PC systems.

sometimes faster sometimes slower...


so i suspect i may have to hook my own ISR to INT 8h or INT 1ch i dun know...

may i get help in doing this ??


can this be done in assembly language, C language or inline assembly ??


Please reply if you know this area. I desperately need some advice !!!!



help appreciated :)




Comments

  • : so i suspect i may have to hook my own ISR to INT 8h or INT 1ch i dun know...

    : may i get help in doing this ??


    You'll probably want to hook INT 1Ch. This interrupt existes solely

    to be hooked by apps that need to be alerted every timer tick. To

    hook it, you can use INT 21h, Function 25h.


    I can provide some example code. What language would you prefer it in?


    Matthew Gross


    URL:http://acheronx.resnet.tamu.edu

  • Hi Matthew Gross,

    I have a similar problem where we are planning to chain our ISR to INT 8h or INT 1ch

    Actually I am converting a windows driver running on nt4 to be run on nt5. In nt4 code the driver used to use irq 0 of the system timer to call a function at each interrupt. But in nt5 we are not able to get the interrput. So we are planning to chain our ISR to the 8h or 1ch interrupt.

    Can I get some help on this?
    Can you please provide with some sample code in C.


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