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How to write a Kernel Q3:

thanks :-)

source:

#include <oskit/machine/base_cpu.h>
#include <oskit/x86/base_gdt.h>
#include <oskit/x86/seg.h>
#include <oskit/x86/base_tss.h>
#include <oskit/x86/base_idt.h>
#include <oskit/x86/trap.h>
#include <oskit/x86/base_trap.h>

extern struct x86_desc base_gdt [GDTSZ];
extern struct x86_tss base_tss ;
extern struct x86_desc base_idt [IDTSZ];   /*IDTSZ = 256*/

extern struct cpu_info base_cpuid ;   /* cpu info filled by base_cpu_init*/
extern struct gate_init_entry base_trap_inittab [];



main()
    {
        /*base_cpu_setup(void);*/     /* Can I have this rather than all init below?
*/
         base_gdt_init();                     /* init the default oskit GDTs*/
         base_gdt_load();                  /* load proper values of gdt*/
         base_idt_load();                   /* point all traps, hard & soft to our
table*/
         base_trap_init();
         base_tss_init();
         base_tss_load();


         printf("Hello World\n");
     }

In the above code I just simple like to initialize all the oskit base structure. Are
there anyhting that I missed? Please modify the code for me.

Thanks

Jammi


Voon-Li Chung wrote:

> > 2. Is the IDT already initialize? How can I put my own traps like for example
> > Id like to create my own customized traps for divide overflow, memory
> > protection. etc.
> No it isnt. To do that, you need to execute the following functions:
>          base_idt_load();
>          base_trap_init();
> If you look at the flux documentation, the IDT structures flux provides is
> just an array of functions. After this call, they are all the default
> handlers, which tells you the state of the machine and the name of the
> trap, but if you make the appropriate entry point to your handler, in
> conjunction with flux's trap information structure, you can write your
> own.
>
> > 3. Can anyone show me how to initialize a call gate? Just one simple function
> > will do. :-)
> That isn't as easy as it sounds. It requires manipulation of the GDT (look
> at the flux documentation) and bitwise arithmetic. It would be better if
> you looked at the intel documentation relating to call gates. I have a
> copy at http://www.cs.uwa.edu.au/docs/intel/386-guide
> don't let the fact that its a 386 guide fool you. The major differences
> between pentiums and the 386 is the presence of an fpu and speed, that's
> all.

Ya I know that there are bits that I have to tweaks but what I means and my purpose
why I join the oskit mailing list is that I assume that oskit will do some work for
me about that bitwise manipulation. I'm not concern on how slow my system be later.
Its up to the oskit developer I guess to optimized their code but I trust them
anyway. Well I just want to handle my programming all in C or C++ which oskit offers.
:-). If there is a default that oskit provides me, I guess, Id be more happy to use
rather than use oskit and tweaks something inside it. I want also my kernel to be
totally upgradable so that next release of this kit will not do me much work but
instead just compile my kernel sweetly like a cake. :-)

Questions:

1.


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