trouble loading function calls

[assembler01]

I use for my kernel the mikeos bootloader (http://mikeos.berlios.de/). I checked in the mikeos kernel and saw how the segments were setup:

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cli
mov ax, 0
mov ss, ax
mov sp, 0FFFFh
sti
cld
mov ax, 2000h
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax

And before you question it, yes I know about segments well enough to have made my own hello world bootloader (with a function call), but I found it difficult to make a bootloader to load my kernel. Anyway, I put the above code into my (16 bit) kernel, included the functions for my kernel, and proceeded to load the kernel (I have it in a partition in my hdd) with QEMU, it booted up, told me it found the kernel but the kernel didn't do anything, so I went back to the editor and made a small thing it would do at startup (after the segments were loaded):

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mov ah, 0Eh
mov al, 'o'
int 10h

When I booted it up it had printed the "o" char to the screen which meant that the system calls where the only things that didn't work. How do I get the system calls to work?

[bubach]

What system calls? You said the kernel didn't do anything, and you then added the BIOS call to print a character. Which worked. So I don't see any problem. If you have additional kernel code that doesn't work, it might be a good idea to show it.

[assembler01]

Sorry, forgot about that.

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main:
  call clean_all ; will clear the screen and clean out the GP regs
  .string: db 'Successfully booted!', 0
  mov si, .string
  call print
  hlt

; include the functions:
%include "screen.asm"
%include "clean.asm"

[Unkn0wn1]

Have you set the origin of the kernel. And also, what fs are you using in the disk image. Seeing the other files may help, as I am working on something realmode so know my way around...

Also, before you put the HLT instruction at the end of the kernel, put a CLI too. Otherwise, any interrupts will lead to a triple-fault and pulsing of the CPU's RESET pin

[assembler01]

What do you mean by "origin of kernel". I use fat12 fs. Here is the print function:

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print:
  pusha
.loop:
  lodsb
  cmp al, 0
  je .done
  mov ah, 0eh
  mov bh, 00h
  int10h
  jmp .loop
.done:
  popa
  ret

And here is the cleaning function:

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clean_all:
  ; clear screen
  mov ax, 0600h
  mov bh, 07h
  mov cx, 0000h
  mov dx, 7924h
  int 10h
  ; clean the regs
  mov ax, 0
  mov bx, 0
  mov cx, 0
  mov dx, 0
  mov si, 0
  mov di, 0
  ret

[Combuster]

The problem is much more simple. You wrote:

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  .string: db 'Successfully booted!', 0

The processor sees the following instructions:

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   0:   e8 1c 00                call   0x1f    ; first instruction
   3:   53                      push   %bx     ; we come back here after the call and er.... what?
   4:   75 63                   jne    0x69    ; oops
   6:   63 65 73                arpl   %sp,0x73(%di) 
   9:   73 66                   jae    0x71    
   b:   75 6c                   jne    0x79    
   d:   6c                      insb   (%dx),%es:(%di)
   e:   79 20                   jns    0x30    
  10:   62 6f 6f                bound  %bp,0x6f(%bx)
  13:   74 65                   je     0x7a
  15:   64 21 00                and    %ax,%fs:(%bx,%si)

In other words: keep data away from code.



@Unkn0wn1: Please do not suggest random stuff unless you can also post proof that it's the problem at hand. This is not the first time you were posting irrelevant stuff and you just managed to confuse the OP

[assembler01]

I put the .string in the data section but the function calls do not work.