Interrupt help

[beyondsociety]

Could Somebody give me a example of how to create and set up a interrupt handler.

Also examples of how to program the pic and the interrupt service routine.

[Warmaster199]

Interrupt handler entry point...

Code: Select all

   push gs      
   push fs      
   push es      
   push ds
   push ss
   pusha      
   mov eax, KERNEL_DS   
   mov ds,eax      
   mov es,eax      
   mov fs,eax      
   mov gs,eax
   sti
   mov eax,esp      
   push eax
   mov eax, _handler_name
   call eax
   add esp,4
   pop eax
   cli
   popa
   pop ss
   pop ds      
   pop es
   pop fs
   pop gs
   iret

Set-up an interrupt gate... Set-up the idt first for this to work. To set a vector(Intr gate), call as:
void set_intr_gate(int vector, void *addr);
...and now:

Code: Select all

_set_intr_gate:
    push ebp
    mov ebp,esp
    push ebx
    pushad
    mov eax,8
    mul byte [ebp + 8]
    mov ebx,eax
    add ebx,idt
    mov eax,[ebp + 12]
    mov [ebx],ax
    shr eax,16
    mov [ebx + 6],ax
    popad
    pop ebx
    pop ebp
    ret

; 256 ring 0 interrupt gates
idt:
%rep 256
    dw 0
    dw KERNEL_CS
    db 0
    db 8Eh
    dw 0
%endrep
idt_end:

idt_ptr:
    dw idt_end - idt - 1
    dd idt

...MANY OS'es made by us hobbyist use the above code or something very similar. LINUX has a similar variant. Mainly because this is the only easy way to do it...