Re: [Mingw-users] problem calling C functions from nasm

[Tor H. <thu...@ho...>]

>From: "Luke Dunstan" <cod...@ho...>
>To: thu...@ho..., min...@li...
>Subject: Re: [Mingw-users] problem calling C functions from nasm
>Date: Thu, 13 Feb 2003 10:03:34 +0800
>
>
>
> >From: "Tor Husabø" <thu...@ho...>
> >To: min...@li...
> >Subject: Re: [Mingw-users] problem calling C functions from nasm
> >Date: Wed, 12 Feb 2003 22:53:19 +0100
> >
> >here´s the source code:
> >
> >This is the C part:
> >
> >/* call_asm.c */
> >
> >int asm_func(void);
> >
> >main()
> >{
> >	int return_from_malloc;
> >
> >	return_from_malloc = asm_func();
> >	printf("0x%08x\n", return_from_malloc);
> >	return 0;
> >}
> >
> >
> >This is the assembly part:
> >; ASM_FUNC.ASM
> >segment .text
> >extern _malloc
> >global _asm_func
> >
> >_asm_func:
> >    push dword 8  ;I'm not sure of the syntax to force the type
> >    call _malloc
> >    add esp, 4
> >    ret
> >; end of _asm_func
> >
> >Does this seem okay to you?  I can´t see anything wrong with it myself...
>
>It works fine for me with these command lines:
>
>nasmw -f win32 asm_func.asm -o asm_func.o
>gcc call_asm.c asm_func.o -o call_asm.exe
>$ ./call_asm.exe
>0x003f2bf0
>
>Please note that the "win32" format is a slight variation of COFF (see the 
>nasm manual), so you DO need to use it, but in such a simple example it 
>_might_ not matter. The file names you gave here are different to your 
>original example, so did you confirm that this example actually crashes for 
>you? I tried nasm 0.98.22 with both GCC 3.2 and 3.2.2. If it does crash for 
>you then maybe you should try debugging it using GDB or at least a bunch of 
>printf statements.
>
>Luke
>
>
> >
> >>From: "Luke Dunstan" <cod...@ho...>
> >>To: Tor Husabø 
><thu...@ho...>,<min...@li...>
> >>Subject: Re: [Mingw-users] problem calling C functions from nasm
> >>Date: Mon, 10 Feb 2003 09:32:33 +0800
> >>
> >>
> >>----- Original Message -----
> >>From: "Tor Husabø" <thu...@ho...>
> >>To: <min...@li...>
> >>Sent: Monday, February 10, 2003 5:55 AM
> >>Subject: [Mingw-users] problem calling C functions from nasm
> >>
> >>
> >> > Has anyone succeeded in calling C functions from nasm routines? I use 
>nasm
> >> > version 0.98.34 and mingw-gcc-3.2,.  I assemble like this: nasm 
>caller.asm
> >> > -f coff -ocaller.o,
> >> > and then I say: gcc caller.o called_func.c -otestprog.exe.
> >> >
> >> > the asm routine is called from main(), and does nothing else than 
>calling
> >>a
> >> > c function, no arguments or anything.  sorry I dont have the code 
>with ´me
> >> > to show you, but it´s as simple as possible, both in C and asm.  but 
>it
> >> > crashes with no messages from winXP every time.  the equvialent 
>routine
> >> > written in GNU assembly works fine.  What am I doing wrong?
> >> >
> >> > The guys at nasm.sourceforge.net wasn´t interested in this problem, 
>so
> >> > please help!
> >>
> >>First try using "-f win32" instead of "-f coff", but otherwise I think
> >>you'll have to show the nasm and C source code before anyone can 
>diagnose
> >>your problem. You may also use GDB (5.2.1 preferably) to debug the 
>program.
> >>
> >>Luke
>

Ok, nasm with ´-f  win´ did the trick.  Guess I just haven´t noticed before 
that the files then get the extension '.obj' instead of just '.o', and used 
the same object  files over again when I thought I used the ones assembled 
with '-f'.  What a ridiculous mistake :)

But thanks anyway, guys...

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