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Code: Select all

_int0:
   cli         ; disable interrupts
   push eax      ; store the current state of cpu
   push ebx      
   push ecx
   push edx
   push ebp
   push edi
   push esi
   push es
   push ds
   push fs
   push gs

   mov eax, 0
   mov gs, eax
   mov fs, eax
   mov eax, 0x10      ; LINEAR_DATA_SEL == 0x10
   mov es, eax
   mov ds, eax

        mov eax, 0
   call IntHandler      ; call the interrupt handler

   pop gs         ; begin to restore the saved cpu state
   pop fs
   pop ds
   pop es
   pop esi
   pop edi
   pop ebp
   pop edx
   pop ecx
   pop ebx
   pop eax
   sti          ; re-enable interrupts
   iretd         ; return 

Code: Select all

void IntHandler(unsigned int x)
{
  char* msg[] = {"Divide Error Exception!", "blah", "blah2" }; 
  kprintf("x is: %x\n", x);
  // kprintf("%s\n", msg[x]);
  kprintf("Halting the CPU...");
  asm("cli");
  asm("hlt");
}

And I do a simple: x += x / 0; to trigger the divide by 0 exception in kernel

My handler gets called but the argument that is passed to the handler is 0x10. I tried assigning 0 to eax before calling the function. Yet when I print the argument it is always 0x10... Can anyone please shed light on this ?? 

thanks

Code: Select all

extern  _IntHandler to the top of the asm file so that LD can find the function
Global  _xxxx ->export function _xxx in asm to c as xxxx(...)
Extern _xxxx -> import function from C as _xxx in asm (parameters are on stack and you should manage them ie recall how many they are and what size each)

Code: Select all

_int0:        <=== can be any label name ???
   cli         
   pushad
   ...
   ...
   iretd

_int1:        <=== what actually calls this label? CPU? 
   cli
   pushad
   ...
   ...
   iretd