proc Something par1,par2,par3
   ...
endp    

PUSH EBP
MOV EBP,ESP
...
    

FASM uses ESP relative addressing anyway.

Quote:

FASM uses ESP relative addressing anyway.

Not sure what you mean, but proc macro defines the arguments and locals as EBP-based, so that sequence you mention has to be there. The only way to avoid it is by not defining any argument nor locals.

FF75 14       PUSH DWORD PTR SS:[ARG.4]
FF75 10       PUSH DWORD PTR SS:[ARG.3]
FF75 0C       PUSH DWORD PTR SS:[ARG.2]
FF75 08       PUSH DWORD PTR SS:[ARG.1]
FF15 A2204000 CALL DWORD PTR DS:[<&USER32.DefWindowProcW>]    

mindcooler,

There is prologue@proc symbolic constant, it holds the name of macro prologue@proc procname,flag,parmbytes,localbytes,reglist to be expanded at the very beginning of proc.

If all else fails, read the source.

macro prologuedef procname,flag,parmbytes,localbytes,reglist    

 { local loc
   loc = (localbytes+3) and (not 3)
   parmbase@proc equ ebp+8
   localbase@proc equ ebp-loc
   if parmbytes | localbytes
    push ebp
    mov ebp,esp
    if localbytes
     sub esp,loc
    end if
   end if
   irps reg, reglist \{ push reg \} }    

Well, my FASM generates ESP relative code for my arguments:

include 'win32wxp.inc'    

FF75 08          PUSH DWORD PTR SS:[EBP+8]    

In light of this it seems the question is; how do you do ESP addressed arguments?

For those of you that may not be aware of why ESP basing is not normally used, here are some reasons why you might not use it:

1) Calls to other proc's with pushing of parameters requires special handling [...]
2) General purpose push/pop creates a nightmare with accessing local variables and caller parameters.

WindowProc:
 virtual at esp+8
 .wmsg  rd 1
 end virtual

        cmp     [.wmsg],WM_DESTROY
        jne     .exit
        invoke  PostQuitMessage,0
 .exit:
        jmp    [DefWindowProc]    

Is this the way to do subroutines if you do away with proc?

Code:

WindowProc:
 virtual at esp+8
 .wmsg  rd 1
 end virtual

        cmp     [.wmsg],WM_DESTROY
        jne     .exit
        invoke  PostQuitMessage,0
 .exit:
        jmp    [DefWindowProc]    

Extremely hacky way to do things.

Actually it's a nice interface forwarding you have here.

WindowProc:

 virtual at esp+8
 .wmsg  rd 1
 end virtual

        cmp     [.wmsg],WM_DESTROY
        jne     .default
        invoke  PostQuitMessage,0
 .exit:
        xor     eax,eax
        ret     $10
 .default:
        jmp    [DefWindowProc]
.end start    

Extremely hacky way to do things.