array of pointers

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derPENGUIN

Joined: 09 Jul 2006
Posts: 5

derPENGUIN 16 Jul 2006, 06:13

sry, newbie-question...

Good morning.
I want to store some adresses in an array. That is my code:

Code:

DATA
index dd 0x0
offset dd 0x0
count dd 0x0
wp: times 255 dd 0x0

CODE
build_array:
    cmp [index],0
    jnz no_main
    mov [offset],edi
  no_main:
    mov eax,[index]
    inc eax
    mov [wp+eax],edi                ; in edi we got the structure offset
    mov [index],eax
    mov [count],eax
ret

PSEUDO
printf("count:%d\n",[count]); //corrrect
printf("point:%d\n",[wp+someIndex]); //incorrrect

I cannot figure out, where it stores the data, but eax counts fine. What is wrong?
The second question will be: how can I access the content of address, which is written to wp+ìndex?

Thanks

PS.: Using FASM 1.66 on MenuetOS

16 Jul 2006, 06:13

viki

Joined: 03 Jan 2006
Posts: 40
Location: Czestochowa, Poland

viki 16 Jul 2006, 08:04

there is no loop for filling array

Code:


  xor bx,bx
loop:
  mov [array+bx],bx
  inc bx
  cmp bx,5
  jne loop

16 Jul 2006, 08:04

JohnnyReb

Joined: 25 Jun 2006
Posts: 8

JohnnyReb 16 Jul 2006, 10:43

I'm kinda new myself, but try:

mov [wp+eax*4],edi

to index into a DWORD array.

_________________
JohnnyReb
Win if you can, Lose if you must, but always cheat!

16 Jul 2006, 10:43

viki

Joined: 03 Jan 2006
Posts: 40
Location: Czestochowa, Poland

viki 16 Jul 2006, 17:05

and what about this

Code:

mov esi,src
mov edi,dst
mov cx,len
rep stosd

16 Jul 2006, 17:05

derPENGUIN

Joined: 09 Jul 2006
Posts: 5

derPENGUIN 17 Jul 2006, 08:13

Thank you for reply.
viki:
A loop is not needed, because I use it as a function. Its for a library and I dont know the count of calls. And yuor second example, the same, I dont have len.
Johnny:
yes, tha was it. eax*4 works. Now I will try to access the content of this saved addresses. If you have any idea, please tell me.

Much thanks,
Frank

17 Jul 2006, 08:13

JohnnyReb

Joined: 25 Jun 2006
Posts: 8

JohnnyReb 17 Jul 2006, 10:46

Access a DWORD array the same way:

printf("point:%d\n",[wp+eax*4]);

or (if it requires pushing on the stack)

mov esi,[wp+eax*4)
printf("point:%d\n",esi);

_________________
JohnnyReb
Win if you can, Lose if you must, but always cheat!

17 Jul 2006, 10:46

derPENGUIN

Joined: 09 Jul 2006
Posts: 5

derPENGUIN 17 Jul 2006, 21:10

thx, I solved it in this way:
mov edi,[wp+eax*4]
printf("point:%d\n",[edi])

BTW, printf is not an asm keyword, is it? I am really better in C as in asm, but actually I´m coding for Menuet, the output there is with int 40, but I think, that is not related to my problem, therefor I used the C syntax.

Much thanks again and cu with further problems, I´m sure Wink

17 Jul 2006, 21:10

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