ASM Community

I have a super simple .ASM file:

.486
.model flat, stdcall
option casemap:none

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

.code
main:
invoke ExitProcess, NULL
end main

Now when i compile and link it, i get the following (shown with dumppe -disasm):

00401000 start:
00401000 6A00 push 0
00401002 E801000000 call fn_00401008
00401007 CC int 3
00401008 fn_00401008:
00401008 FF2500204000 jmp dword ptr

My questions are:

1. Why at 00401007 is there CC INT 3 Interrupt 3 trap to debugger ?

2. Why is there a call to 00401008 fn_00401008 just to do a JuMP to the ExitProcess routine ?

I guess I am wondering why the code is not like this:

00401000 start:
00401000 6A00 push 0
00401008 FF2500204000 jmp dword ptr


My only guess is that I compiled/linked with debug and the extra call to jmp is there so that the debugger can trap the call, before the jump.

So how do I turn off DEBUG in ML/LINK ?
Regs,

1) 0CCh is there to trap errors - rather weird the masm emites this. Yet a sign that is is
a highlevel assemvler.

2) to do with your typedefs and such (yeah, masm is highlevel). You "CALL" "directly" the API,
which means you go through linker proxies... with some other typedefs and such you can go
directly.

Gotta love FASM even more now:

00401000                    start:

00401000 6A00                   push    0

00401002 FF1535204000           call    dword ptr [ExitProcess]

Source:

Format PE GUI 4.0



include 'stdcall.inc'

include 'import.inc'



stdcall [ExitProcess], 0



section '.idata' import data readable writeable



 library kernel, 'KERNEL32.DLL'

 kernel:

 import ExitProcess, 'ExitProcess'

18.07.2002  09:00                1.536 test_fasm.exe

18.07.2002  08:42                2.560 test_masm.exe

Is there a way to avoid that CALL / JMP to the API?
(didn't bitRAKE post a macro for that?)

Just interested about that.....
/me is future FASM user :grin:

Thanks, never looked in that folder :)

Ain't it good to know that MASM always did it right.

Disassembly



00401000                        start:

00401000 6A00                   push    0

00401002 FF1500204000           call    dword ptr [ExitProcess]

Just used the headers generated by L2EXTIA.EXE

Regards,

hutch@movsd.com :tongue:

Sven,

Do you want to answer the flood of email about why the examples don't work or where are they or how do you write THIS code ?

After being mail bombed for a few versions, splitting it up so that the installation was not automatic and complete would be a formula for a bandwidth crisis that I don't need. :tongue:

Regards,

hutch@movsd.com

Ok, can someone tell me what this tool does and how to run it ?

Regs,

James,

It is a utility that reads the linker data from the standard Microsoft libraries and writes a set of INCLUDE files that are in EXTERNDEF format instead of the format that the default masm prototypes are written in.

It produces a shorter API call but duplicates that call every time so that commonly used APIs like SendMessage() end up generating more code. MASM by default builds the standard PROTOYPE format that produces a lookup table at the end of the binary file and this has some to do with MASM's primary purpose of writing VXD and later format drivers.

The form created by L2EXTIA.EXE produces calls in much the same way as VC. It is there so that people who are interested have the choice in how their binary code is generated.

Regards,

hutch@movsd.com

Old... ermm... Experienced hutch and JAVA? Dont.think.he.likes.the.syntax :)

Better ask at www.RentACoder.com ;)