Is it possible this on "stdcall" macro?

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alorent

Joined: 05 Dec 2005
Posts: 221

alorent 22 Oct 2009, 13:29

Hi guys,

Is it possible in the "stdcall" macro to call it as:

Code:

stdcall  ebx, addr [ebp + 11223344]

I have tried under FASM but it produces error (due to the "addr [ebp + 11223344]")

Under MASM, we can call it as:

Code:

invoke ebx, ADDR [ebp + 11223344]

and it generates:

Code:

lea     eax, [ebp + 11223344]
push   eax
call    ebx

Thanks in advance!

22 Oct 2009, 13:29

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 22 Oct 2009, 13:58

Yes, and it is very simple:

Code:

stdcall  ebx, addr ebp + 11223344

22 Oct 2009, 13:58

alorent

Joined: 05 Dec 2005
Posts: 221

alorent 22 Oct 2009, 14:26

Woww, LocoDelAssembly, thanks!!! Very Happy

By the way, I see that the generated code is:

Code:

lea  edx, [ebp + 11223344]
push edx
call   ebx

Is it possible to control that code generation and use EAX instead of EDX? That is, like:

Code:

lea  eax, [ebp + 11223344]
push eax
call   ebx

I have been looking at the PROC32.INC file, but don't see that code being generate at all.

Thanks!!!

22 Oct 2009, 14:26

r22

Joined: 27 Dec 2004
Posts: 805

r22 22 Oct 2009, 15:02

@alorent
Try the WIN32AX.INC and WIN32AXP.INC files.

The ADDR is part of the PUSHD macro. So replace

Code:

lea edx,[..address]

with

Code:

lea eax,[..address]

But if you start editing the includes you'll need to take note when you use a newer/upgraded version of FASM to re-implement your changes.

22 Oct 2009, 15:02

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 22 Oct 2009, 15:04

You have to look in WIN32?X*.inc instead:

Code:

  match pushd =addr var,pushd value \{ \local ..opcode,..address
   virtual at 0
    label ..address at var
    mov eax,dword [..address]
    load ..opcode from 0
   end virtual
   if ..opcode = 0A1h
    push var
   else
    lea edx,[..address]
    push edx
   end if
   pushd equ \}

You can't change the register unfortunately (I mean, without changing the includes). However, if you need such control, besides doing LEA and then using EAX as argument (which only works you need a single argument with the ADDR loaded into EAX), I suggest you not using stdcall at all and doing plain PUSH/CALL yourself. IMHO, macros should only be used when (1) you perform the same task several times, and (2) when you would perform the task in the very same way each time without macros.

PS: Well, r22 replied first but I think it is still somewhat important what I've said above Razz

22 Oct 2009, 15:04

alorent

Joined: 05 Dec 2005
Posts: 221

alorent 22 Oct 2009, 18:28

Thanks a lot guys!!! Very Happy

22 Oct 2009, 18:28

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