Error: invalid expression

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Cos

Joined: 06 Dec 2018
Posts: 3

Cos 06 Dec 2018, 05:29

I just started Assembly class, and got stuck with this error wile compiling :

flat assembler version 1.73.04 (1048576 kilobytes memory)
1_console.asm [34]:
import kernel,\
C:\Program Files (x86)\fasmw\INCLUDE/macro/import32.inc [31] import [5]:
if used label
processed: if used
error: invalid expression.

I double checked invirmental variables, code, and don't have any idea what is wrong.

Whhat I understand that there is problem with 'if used' label within import32.inc file.

Last edited by Cos on 06 Dec 2018, 17:40; edited 1 time in total

06 Dec 2018, 05:29

DimonSoft

Joined: 03 Mar 2010
Posts: 1228
Location: Belarus

DimonSoft 06 Dec 2018, 08:24

One line might not always be enough. One possibility is that kernel module has not been defined with library macro, another one might be in a way you’re defining the functions to import in the next few lines (for some definition of “few”).

06 Dec 2018, 08:24

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20423
Location: In your JS exploiting you and your system

revolution 06 Dec 2018, 12:06

Please show more source to give context. import is a macro that takes many parameters, and we can't see the other lines after the line continuation trailing backslash.

06 Dec 2018, 12:06

Cos

Joined: 06 Dec 2018
Posts: 3

Cos 06 Dec 2018, 14:50

There is source code I used:

Code:

format PE console

entry start

include 'win32a.inc' 

; ===============================================
section '.text' code readable executable

start:
        ; Your program begins here:
        inc     eax
        inc     eax
        dec     eax
        inc     eax

        ; Exit the process:
        push    0
        call    [ExitProcess]
        
; ====================================
; Imports section:


section '.idata' import data readable

library kernel,'kernel32.dll'

import  kernel,\

        ExitProcess,'ExitProcess'

06 Dec 2018, 14:50

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20423
Location: In your JS exploiting you and your system

revolution 06 Dec 2018, 22:20

So the problem is the blank line after the import. If you remove the blank line then it will assemble.

Code:

format PE console

entry start

include 'win32a.inc'

; ===============================================
section '.text' code readable executable

start:
        ; Your program begins here:
        inc     eax
        inc     eax
        dec     eax
        inc     eax

        ; Exit the process:
        push    0
        call    [ExitProcess]

; ====================================
; Imports section:


section '.idata' import data readable

library kernel,'kernel32.dll'

import  kernel,\
        ExitProcess,'ExitProcess'

The backslash is for line continuation so another option is to add a second backslash:

Code:

format PE console

entry start

include 'win32a.inc'

; ===============================================
section '.text' code readable executable

start:
        ; Your program begins here:
        inc     eax
        inc     eax
        dec     eax
        inc     eax

        ; Exit the process:
        push    0
        call    [ExitProcess]

; ====================================
; Imports section:


section '.idata' import data readable

library kernel,'kernel32.dll'

import  kernel,\
\
        ExitProcess,'ExitProcess'

06 Dec 2018, 22:20

Cos

Joined: 06 Dec 2018
Posts: 3

Cos 07 Dec 2018, 00:22

Thanks, its works now. Appreciate your help.

07 Dec 2018, 00:22

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