Using Fasm with Visual C++

Hi friends,

Here is an example on how to use Fasm with VC++ , a simple hello world application using the StdOut function coded in Fasm

Hello world code:

Code:

extern int __stdcall StdOut(char *msg);

void main(int argc,char *argv[])
{
StdOut("Hello world");
}

Code:

format MS COFF

include 'win32.inc'
include 'StdOut.imp'

public StdOut as "_StdOut@4"

section '.text' code readable executable

proc StdOut,lpszText
  
    hOutPut  dd ?
        bWritten dd ?
        sl       dd ?
     enter
       invoke GetStdHandle,STD_OUTPUT_HANDLE
       mov [hOutPut],eax
        invoke lstrlen,[lpszText]
      mov [sl],eax
        lea eax,[bWritten]
        invoke WriteFile,[hOutPut],[lpszText],[sl],eax,NULL
        mov eax,[bWritten]
     return

The original StdOut function can be found in Hutch's masm32.lib
This function needs to be exported with the decorated form, _StdOut@4
You will find the revised stdcall macro supporting indirect function fall for MS Link

Here is my simplified C start-up code for console applications:

Code:

.386
.model flat,stdcall
option casemap:none

include \masm32\include\kernel32.inc

__getmainargs PROTO C :DWORD,:DWORD,:DWORD,:DWORD
main PROTO C :DWORD,:DWORD

.data?
argc dd ?
argv dd ?
env dd ?
.code
start:
        invoke  __getmainargs,ADDR argc,ADDR argv,ADDR env,0
        invoke main,argc,argv
        invoke ExitProcess,0
END start

Finally,building the executable Sample.exe:

Code:

set fasminc=c:\fasmw\include
scan StdOut.asm -ic
\fasm\fasm StdOut.asm StdOut.obj

\progra~1\micros~2\vc98\bin\cl /c /Zl /Ogtyb2 /Gs /G6 /Gz /Zp1 /FAs /FaSample.asm /FoSample.OBJ Sample.c
\masm32\bin\link /NODEFAULTLIB /ENTRY:start /SUBSYSTEM:CONSOLE /LIBPATH:c:\masm32\lib /out:Sample.exe startc.obj Sample.obj StdOut.obj kernel32.lib user32.lib msvcrt.lib

Here is also my GUI version of C start-up code:

Code:

.386
.model flat,stdcall
option casemap:none

WinMain PROTO :DWORD,:DWORD,:DWORD,:DWORD

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc

.data?
hInstance HINSTANCE ?

.code
start:
        invoke GetModuleHandle, NULL
        mov    hInstance,eax
        invoke GetCommandLine
        invoke WinMain, hInstance,NULL,eax,SW_SHOWDEFAULT
        invoke ExitProcess,eax
END start