Struc array

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Jin X

Joined: 06 Mar 2004
Posts: 133
Location: Russia

Jin X 17 Aug 2018, 13:20

Hello!

1. How can I define array of uninitialized structures?

Code:

struc POINT
{
  .x dd ?
  .y dd ?
}

Points POINT 10 dup (?)  ; error!!!

And then use mov eax,[Points.y+edx*8]

2. Can I define structure without label name?

Code:

POINT ; error

Last edited by Jin X on 17 Aug 2018, 13:25; edited 1 time in total

17 Aug 2018, 13:20

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20515
Location: In your JS exploiting you and your system

revolution 17 Aug 2018, 13:25

1. Your POINT structure doesn't define its size so it will be tricky, but it can be done like this:

Code:

Points POINT ; the first POINT structure
rept 9 {
 local .dummy_label
 .dummy_label POINT
}

2. Macros and Strucs are the same thing except that struc requires a label name. If you want to place structures without a label then you can define a macro of the same name. Macros and Strucs are kept in separate places so you can define both in same code with the same name.

17 Aug 2018, 13:25

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20515
Location: In your JS exploiting you and your system

revolution 17 Aug 2018, 13:28

Jin X wrote:

And then use mov eax,[Points.y+edx*8]

Ideally you would define the size of the structure so that changes will be applied to any code that uses it.

Code:

mov eax,[Points.y+edx*sizeof.POINT]

Last edited by revolution on 17 Aug 2018, 16:46; edited 1 time in total

17 Aug 2018, 13:28

Jin X

Joined: 06 Mar 2004
Posts: 133
Location: Russia

Jin X 17 Aug 2018, 15:10

How can I access some scturture field relative to some address. Something like:

Code:

mov eax,[edx+POINT.y]  ; mov eax,[edx+4]

???

17 Aug 2018, 15:10

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20515
Location: In your JS exploiting you and your system

revolution 17 Aug 2018, 16:08

Jin X wrote:

How can I access some scturture field relative to some address. Something like:
Code:
mov eax,[edx+POINT.y]  ; mov eax,[edx+4]    
???

You have to define POINT.y as a label

Code:

struc POINT {
y dd ?
}
POINT POINT ;define POINT.y label

17 Aug 2018, 16:08

Jin X

Joined: 06 Mar 2004
Posts: 133
Location: Russia

Jin X 17 Aug 2018, 16:42

Something like this? Smile

Else I will get addressing relative to POINT (label definition) offset.

Code:

virtual at 0
  POINT POINT
end virtual

17 Aug 2018, 16:42

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20515
Location: In your JS exploiting you and your system

revolution 17 Aug 2018, 16:45

Yes, if you don't need the memory allocated, and only want the label values.

17 Aug 2018, 16:45

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