question about "struct"

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ouadji

Joined: 24 Dec 2008
Posts: 1081
Location: Belgium

ouadji 25 Oct 2010, 21:56

Code:

struct toto
v1 dd ?
ends

mov eax,mystruct + 4          ;a) does compile
mov eax,mystruct.mylocal        ;b) does not compile

mystruct toto

.mylocal:

dw1 dd ?

;Why "b" does not compile ?
;mystruct is not a global label ?
;and if "mystruct" is not a global label, then why "a" does compile ?

_________________
I am not young enough to know everything (Oscar Wilde)-

25 Oct 2010, 21:56

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20535
Location: In your JS exploiting you and your system

revolution 25 Oct 2010, 23:39

struct != struc

Use the tools provided by fasm to see what struct does: "PREPSRC.INC"

25 Oct 2010, 23:39

ouadji

Joined: 24 Dec 2008
Posts: 1081
Location: Belgium

ouadji 26 Oct 2010, 00:00

PREPSRC.INC ?
thank revolution you for your reply,
but that does not help me much.

_________________
I am not young enough to know everything (Oscar Wilde)-

26 Oct 2010, 00:00

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20535
Location: In your JS exploiting you and your system

revolution 26 Oct 2010, 00:01

In the "TOOLS" folder.

26 Oct 2010, 00:01

ouadji

Joined: 24 Dec 2008
Posts: 1081
Location: Belgium

ouadji 26 Oct 2010, 00:05

yes, I know, I've seen.
and what do I do with this file?
or it is already too late and my brain is sleeping ...
it's possible too!
Confused

_________________
I am not young enough to know everything (Oscar Wilde)-

26 Oct 2010, 00:05

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20535
Location: In your JS exploiting you and your system

revolution 26 Oct 2010, 00:12

Go to the sub folder TOOLS\WIN32 and assemble "PREPSRC.ASM"

26 Oct 2010, 00:12

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8367
Location: Kraków, Poland

Tomasz Grysztar 26 Oct 2010, 07:40

Actually, it it not really related to "struct" being not the same as "struc", since with "struc" exactly the same happens:

Code:

struc toto
{
 .v1 dd ?
}

mov eax,mystruct + 4            ; does compile
mov eax,mystruct.mylocal        ; does not compile

mystruct toto

.mylocal:

dw1 dd ?

It is because "mystruct.v1" is a "global" label from the point of view of NASM-style locals - therefore ".mylocal" can be accessed as "mystruct.v1.mylocal". These features don't mix well.

26 Oct 2010, 07:40

ouadji

Joined: 24 Dec 2008
Posts: 1081
Location: Belgium

ouadji 26 Oct 2010, 08:12

Code:

struct toto
v1 dd ?
ends

mov eax,mystruct.v1.mylocal

mystruct toto

.mylocal:

yes indeed, this above compiles without problem.
"mystruct.v1" is a "global" label .... ok, understood Tomasz.
(dito for "struct" AND for "struc")
this is very important for the future behavior of wink.
thank you for your explanation.

_________________
I am not young enough to know everything (Oscar Wilde)-

26 Oct 2010, 08:12

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