FASM + C/C++

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b0b

Joined: 22 Jan 2005
Posts: 4

b0b 22 Jan 2005, 04:37

I have looked at some of the tutorials on the net and I have a large C/C++ background. I find it easier to program most of my OS in C/C++.

I read this tutorial and I wanted to use FASM. How would I impliment it though?

22 Jan 2005, 04:37

crc

Joined: 21 Jun 2003
Posts: 637
Location: Penndel, PA [USA]

crc 22 Jan 2005, 12:45

Under which C compiler and host OS?

22 Jan 2005, 12:45

gunblade

Joined: 19 Feb 2004
Posts: 209

gunblade 22 Jan 2005, 13:07

If your looking just for that kernel_start.asm translated.. it should be:

Code:

format ELF
use32
public start
extrn _k_main

start:
call _k_main

cli
hlt

(i know the use32 aint required, i still put it in though, try and stop me Very Happy

)
as you see, very little differences.. check the manual for more info on syntax of fasm, etc..

oh, and there is a difference, this will create an ELF file, but if your on any modern linux distro, you'll be fine, the kernel can execute both aout and ELF fine (aout is becoming antiguated though (i cant spell... its getting old, and being used less, put it that way Smile

))

so assemble that code with fasm kernel_start.asm ks.o

then the rest of the tutorial is the same

edit:
you might have problems with mixing aout and ELF.. but fasm doesnt have a format for aout, and i cant find the header reference, so i cant really code that up. But technically, you should use aout header (anyone else have it handy, feel free to paste it Smile

)

oh, and you dont need the _ before the two k_main's when using ELF, but you do when using aout

Last edited by gunblade on 22 Jan 2005, 13:42; edited 1 time in total

22 Jan 2005, 13:07

mike.dld

Joined: 03 Oct 2003
Posts: 235
Location: Belarus, Minsk

mike.dld 22 Jan 2005, 13:20

I was doing it like this with MSVC++. In FASM:

Code:

format MS COFF

include '%fasminc%\win32a.inc'

; if you want to use come WinAPI funcs, declare them like:
;extrn '__imp__MessageBoxA@16' as MessageBox:dword

macro p_cproc name,[arg] {
 common
  public name as '_'#`name
  cproc name,arg
}

section '.text' code readable executable

p_cproc m_strncpy,p_str1,p_str2,dw_num
    push    edi esi
     mov     edi,[p_str1]
        mov     esi,[p_str2]
        mov     ecx,[dw_num]
        cld
 rep     movsd
       pop     esi edi
     return
endp

After that, C-code:

Code:

extern "C" dword m_strncpy(char*,char*,dword);

_________________
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22 Jan 2005, 13:20

b0b

Joined: 22 Jan 2005
Posts: 4

b0b 22 Jan 2005, 15:06

Im on Windows XP, so I use the DJGPP tools (even if it's DOS).

22 Jan 2005, 15:06

f0dder

Joined: 19 Feb 2004
Posts: 3175
Location: Denmark

f0dder 23 Jan 2005, 12:27

b0b, get the free vc2003 kit from microsoft - it's one of the best performing x86 compilers around, it's very standards compliant, and it's free and with a very liberal license (you can use it to develop your own OS if you want): http://msdn.microsoft.com/visualc/vctoolkit2003/

23 Jan 2005, 12:27

Juras

Joined: 18 Jun 2003
Posts: 23
Location: Belarus

Juras 22 Feb 2005, 21:16

what linker should then be used??? :-O

22 Feb 2005, 21:16

SadKo

Joined: 22 Jun 2004
Posts: 5
Location: Russia

SadKo 19 Nov 2005, 21:43

I use Watcom C/C++ compiler (you can download it on http://www.openwatcom.org/).

19 Nov 2005, 21:43

jdawg

Joined: 26 Jun 2005
Posts: 39

jdawg 03 Dec 2005, 09:35

One question. How did you get away from being forced to produce code for another executable image type than the standard ones for your O.S. using C/C++?

03 Dec 2005, 09:35

DataHunter2009

Joined: 10 Jun 2005
Posts: 144

DataHunter2009 11 Dec 2005, 21:27

When I compile that code kernel_start.asm code, I get a "PE operations on Non-PE file" error in the linker. Any ideas?

11 Dec 2005, 21:27

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