Asm .obj into Devpas(FreePascal)

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sittingduck

Joined: 31 Dec 2007
Posts: 7

sittingduck 08 Jan 2008, 20:50

test.obj:

format MS COFF
extrn var1
mov edx,[var1]
add edx,10
mov [var1],edx
ret

and then:

program MyProgram;
uses crt;

{$ASMMODE INTEL}
{$APPTYPE GUI}
{$MODE FPC}
{$MMX ON}
{$Q-}
{$R-}
{$S-}
{$D-}
{$L test.obj}

var
var1 : Longint; cvar; external;

begin
readln;
end.

Gives:

test.obj(.flat+0x1): undefined reference to `var1'
test.obj(.flat+0xa): undefined reference to `var1'

All i wanna do is using variables & functions.

Please help...

08 Jan 2008, 20:50

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 08 Jan 2008, 23:58

"extrn" is for "importing" external symbol to your module. If you want to "export" symbol from module for other module to use, there is directive "public"

08 Jan 2008, 23:58

sittingduck

Joined: 31 Dec 2007
Posts: 7

sittingduck 09 Jan 2008, 13:27

format ms coff
section '.code' code readable executable

; export symbols
public mymain as '_mymain'
public var1 as '_var1'

mymain:
mov edx,var1
add edx,100
ret

section '.data' data readable writeable
var1 dd 0,0,0,0

Assembles to objectfile.OBJ no errors.
But this:

program MyProgram;
uses crt;

{$ASMMODE INTEL}
{$APPTYPE GUI}
{$MODE FPC}
{$MMX ON}
{$Q-}
{$R-}
{$S-}
{$D-}
{$L objectfile.OBJ}

var var1,_var1: LongInt;

begin
var1:=20;
_var1:=67;
mymain;
_mymain;

WriteLN(var1,'...',_var1);
readln;
end.

why.pas(20,3) Error: Identifier not found MYMAIN
why.pas(20,9) Error: Illegal expression
why.pas(21,2) Error: Identifier not found _MYMAIN
why.pas(21,9) Error: Illegal expression
why.pas(26) Fatal: There were 4 errors compiling module, stopping

09 Jan 2008, 13:27

OzzY

Joined: 19 Sep 2003
Posts: 1029
Location: Everywhere

OzzY 11 Jan 2008, 04:09

I never tried to link external .obj with free pascal.

But fpc's inline asm is easy:

Code:

program project1;
{$APPTYPE CONSOLE}
{$ASMMODE INTEL}

function addnum(x, y : integer) : integer;
var
res : integer;
begin
asm
    pusha
    mov eax,x
    mov ebx,y
    add eax,ebx
    mov res,eax
    popa
end;
    addnum:=res;
end;



begin
     writeln('The sum is ',addnum(2,3));
end.

I hope it helps.

It just reminds me how wonderful language pascal is. I'll start using it more. Razz

11 Jan 2008, 04:09

sittingduck

Joined: 31 Dec 2007
Posts: 7

sittingduck 11 Jan 2008, 21:15

OzzY wrote:

I never tried to link external .obj with free pascal.

But fpc's inline asm is easy:
Code:
program project1;
{$APPTYPE CONSOLE}
{$ASMMODE INTEL}

function addnum(x, y : integer) : integer;
var
res : integer;
begin
asm
    pusha
    mov eax,x
    mov ebx,y
    add eax,ebx
    mov res,eax
    popa
end;
    addnum:=res;
end;



begin
     writeln('The sum is ',addnum(2,3));
end.    
I hope it helps.

It just reminds me how wonderful language pascal is. I'll start using it more.

That works like a charm.
But why are the color of asm code same as the background in DevPas?

11 Jan 2008, 21:15

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