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Index > Main > Fasm 1.73 virtual and interface

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Roman



Joined: 21 Apr 2012
Posts: 678
Roman
I try virtual whit strut.
Work fine.
Code:
Interface Im,\
    R, P, Stop
Virtual at eax
Som Im
End virtual
    

Call [Som. Stop]

In Ida Pro I get call large dword 08h
But not call [eax+8]
Post 09 Feb 2020, 12:46
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ProMiNick



Joined: 24 Mar 2012
Posts: 558
Location: Russian Federation, Sochi
ProMiNick
interface don`t structurize data!!!
so, Som declared as object by single dword(or qword) in eax, and assumed that is pointed to interface structure.
But interface self is only abstraction - it is ALWAYS zero based structure.
ptrsize=4(32bit)|ptrsize=8(64bit)
So
Som = eax
Som.R = ptrsize*0
Som.P = ptrsize*1
Som.Stop = ptrsize*2

use "call[Som+Im.Stop]" instead.
[edited]I a bit hurried: even that is incorrect.

in eax+ptrsize located another variable.
so we for start should dereference ptr: mov eax,[Som]
and only after that call [eax+Som.Stop] ; Som.Stop equal to Im.Stop
Post 09 Feb 2020, 13:46
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