Linking FASM MS64 COFF static object with GCC

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system error

Joined: 01 Sep 2013
Posts: 670

system error 09 Apr 2016, 06:49

Never used MS COFF/MS64 COFF before in my life but last night I managed to link the 32-bit version, but no such luck with MS64 COFF. I used this;

Code:

 gcc test.obj -o test.exe

It emits "File format not recognized" or something like that

The code;

Code:

;test.asm
format MS64 COFF

public main ;as 'main'
extrn printf

section '.data' data readable writeable align 16
align 16
x dq -0.1756522
fmt db '%f',0
msg db 'Hello World',0ah,0

section '.code' code readable executable align 16
align 16
main:
        sub     rsp,32
        mov     rcx,msg
        call    printf
        movq    xmm0,[x]
        mov     rcx,fmt
        call    printf
        add     rsp,32
        ret

What did I miss?

EDIT: test.obj, not test.o

09 Apr 2016, 06:49

system error

Joined: 01 Sep 2013
Posts: 670

system error 09 Apr 2016, 07:27

For comparison. this is the 32-bit version that works

Code:

;gcc test.obj -o test.exe
format MS COFF

public main as '_main'
extrn _printf

main:
        push    ebp
        mov     ebp,esp
        push    msg
        call    _printf
        add     esp,4
        sub     esp,8
        push    [x]
        fld     dword[x]
        fstp    qword[esp]
        push    fmt
        call    _printf
        add     esp,12
        mov     esp,ebp
        pop     ebp
        ret

x dd -0.1756522
fmt db '%f',0
msg db 'Hello World LOL LOL',0ah,0

09 Apr 2016, 07:27

eeikel

Joined: 17 Jun 2013
Posts: 7
Location: NL

eeikel 14 Apr 2016, 09:32

in c: void aFunction();

Code:

 
     format MS64 COFF 
     public aFunction
     section '.data' data readable writeable align 16
     the_x dq -0.1756522 
     fmt db '%f',0 
     msg db 'Hello World',0ah,0 
     section '.code' code readable executable ;align 16
     extrn 'printf' as _printf
                                        aFunction:

                                                  sub     rsp,32
                                                  mov     rcx,msg 
                                                  call    _printf
                                                  movq    xmm0, [the_x] 
                                                  mov     rcx, fmt ; rcx returned value
                                                  call    _printf
                                                  add     rsp,32 
                                                  ret

14 Apr 2016, 09:32

system error

Joined: 01 Sep 2013
Posts: 670

system error 15 Apr 2016, 07:35

thanks man. But when I use GCC, shouldn't I comply to the C structure (main, _main, WinMain@xyxyxyxyxyxyzz, mainCRTStartup and stuff)?

15 Apr 2016, 07:35

eeikel

Joined: 17 Jun 2013
Posts: 7
Location: NL

eeikel 15 Apr 2016, 08:11

No you just do in c:

Code:

void aFunction();

int main(){
                 aFunction();

return 0;
}

link the file test.OBJ
in eclipse project -> properties -> c/c++ build -> tab: tool settings -> mingWC linker -> Miscellanious -> other objects

15 Apr 2016, 08:11

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