Some IDT Code...in C

[df]

this is my keyboard isr

Code: Select all

    .globl   _keyboard_isr
    .align   4
_keyboard_isr:
    pushl   %eax
    pushl   %ds
    pushl   %es
    pushl   %fs
    pushl   %gs

    movl    $0x10, %eax
    movw    %ax, %ds
    movw    %ax, %es
    movw    %ax, %fs
    movw    %ax, %gs

   call   _keyboard

    movl    $0x20, %eax
    outb    %al, $0x20

   popl   %gs
   popl   %fs
   popl   %es
   popl   %ds
    popl   %eax
    iret

[jrfritz]

Sorry but I would like know the virtual address thing...

And if you used my inasm("") macro you wouldn't have to have externel modules and you could use NASM code.(mostly)

[DarylD]

I probably didn't explain myself very well, when I say virtual address what I mean is have you got a GDT and page tables set up that will allow access to 0xFFFFFFFF because that address would be 4GB, so unless you have 4GB of ram it will fail, and even then I doubt it would work.

You need to set esp to point to an area of physical memory, where is your stack defined in your boot.asm?

Hang on, let me have a look at your code see if I can suggest anything.

[jrfritz]

My stack is in the:
mov ax, 0x10
mov ss, ax
mov esp, 0xFFFF

part.

Wait...if I want 0xFFFFFFFF don't I need the a20?

[DarylD]

Yes, but you need to decide where your stack is going. For example in my case, I use _end (which is a symbol created by gcc) to work out the end of my kernel, then I set aside a few pages after this and set esp to end of this region, this way I know that it will not get clobbered and that it also isn't off somewhere strange (which you really don't want because of inexplicable bugs later.)

Basically, try not to use a "guessed" value for esp, it probably won't work at all, if it does, it will be unreliable.

[beyondsociety]

[attachment deleted by admin]

[jrfritz]

So, where do you think I could put my stack (just for testing...i'll think of a better idea later)?

[jrfritz]

The boot_pm.asm won't work.

[jrfritz]

Ok...the problem is not my stack.

The problem is that I get a GPF. Why? I'm using the exact same code I posted before.

[Unexpected]

Thnx df
What is doing this code:

Code: Select all

     movl  $0x10, %eax
     movw  %ax, %ds
     movw  %ax, %es
     movw  %ax, %fs
     movw  %ax, %gs

Why my IRQ calls only one time?
Next time when I pressing a key, IRQ doesn't call...

[df]

you realise setting your stack to 0xffff , it should be aligned on 4 byte boundary, so 0x10000 or 0xfffc, etc. since your pushing dwords in pmode, cpu is optimised for dword alignment.

if you need to put kernel stack somewhere.. have some data space in your kernel just for kernel stack, and point your esp to that...

while my kernel is setting up, my esp situated at 512kb mark.

[df]

Thnx df
What is doing this code:

Code: Select all

     movl  $0x10, %eax
     movw  %ax, %ds
     movw  %ax, %es
     movw  %ax, %fs
     movw  %ax, %gs

Why my IRQ calls only one time?
Next time when I pressing a key, IRQ doesn't call...

my gdt selectors = null 0, code32 (8), data32 (0x10)
so its putting data32 into ds/es/fs/gs

[jrfritz]

Unexpected, after the IRQ before the IRET you need a

outportb( 0x20, 0x20 );

[Unexpected]

Can I do like this:

Code: Select all

IRQ1:
PUSHA
CALL _C_Func
POPA
IRETD

If no then why?

[jrfritz]

And then in your c function do this:

void getkeyboardirq()
{
   int something = inportb( 0x60 );

   putch( asciiNonShifted[something] );

   outportb( 0x20, 0x20 );
}