Re: Structures in Assembly Language

From: Betov (betov_at_free.fr)
Date: 08/18/04 

Date: 18 Aug 2004 16:04:18 GMT

"Randall Hyde" <randyhyde@earthlink.net> écrivait news:RwKUc.6023$3O3.5451
@newsread2.news.pas.earthlink.net:

> Hi All,
>
> [... Tons of insane bullshits, as usual...]

To beginners:

* Take care of such Posts: They are not at all designed
to help you in any manner, at understanding anything
about Assembly. Their only purpose is to misslead you,
and to sell you a pure horror, called HLA.

* There is no concept similar to C-Like Structures in
Assembler and there will never be any, for the very simple
reason, that, an Assembler offering C-Like Structures is
no longuer an Assembler, but, an Assembly Compiler.

* The implementation of C-like Structures in an Assembly
Compiler have only inconvenients and no advantage.

- What is a C-Like Structure:

A C-Like Structure is the Abstration of a Data Chunk, that
is nothing but a group of hidden Equates. The reason why
you cannot have hidden Equates, with an Assembler, is that
an Assembler is not a Tool that _hides_ anything, but a Tool
that _shows_ everything possible to show.

- How to implement Structures in an "Asm Compatible" way:

Though C-Like Structures are nothing but hidden Equates,
and though you can perfectely, of course, declare these
Equates, the Assembly Structures may come under 3 forms:

* Equates set (universal usage)
* Stack Displacements (For Structures on the Stack)
* Simple Data Sets.

Here is one example of the inaccurate things the wrong
choice of C-Like Structures would push you to do. This
one comes from a MASM32 Demo, called "RichEdit":
____________________________________________________

WinMain proc hInst :DWORD,
             hPrevInst :DWORD,
             CmdLine :DWORD,
             CmdShow :DWORD

      ;====================
      ; Put LOCALs on stack
      ;====================

      LOCAL Wwd :DWORD
      LOCAL Wht :DWORD
      LOCAL Wtx :DWORD
      LOCAL Wty :DWORD
      LOCAL lpArg:DWORD
      LOCAL sWid :DWORD
      LOCAL sHgt :DWORD
      LOCAL wc :WNDCLASSEX
      LOCAL msg :MSG

    ; --------------------------------------------------
    ; Fill WNDCLASSEX structure with required variables
    ; --------------------------------------------------
      invoke LoadIcon,hInst,500 ; icon ID
      mov hIcon, eax

      szText szClassName,"Rich_Edit_Class"

            mov wc.cbSize, sizeof WNDCLASSEX
            mov wc.style, CS_BYTEALIGNWINDOW
            mov wc.lpfnWndProc, offset WndProc
            mov wc.cbClsExtra, NULL
            mov wc.cbWndExtra, NULL
            m2m wc.hInstance, hInst
            mov wc.hbrBackground, NULL
            m2m wc.lpszMenuName, NULL
            mov wc.lpszClassName, offset szClassName
            m2m wc.hIcon, hIcon
            invoke LoadCursor,NULL,IDC_ARROW
            mov wc.hCursor, eax
            m2m wc.hIconSm, hIcon

            invoke RegisterClassEx, ADDR wc
________________________________________________________

Notice that all of the Initializations of the Structure
are done, on the Stack, AT RUN-TIME. Such Methods, and,
most of all, their _generalizations_ (in some cases, this
is accurate to do something similar to this...), would
completely defeate any reason for programming Assembly:
Such a Structure should, evidently, be declared in Data,
as simple Data, and it should be initialized, for all the
known Members, AT WRITE-TIME.

The fact that the "Assemblers" (...) pushed by Master Pdf
do not have any integrated feature to support the various
way of doing Structures the proper way, in Assembly, is
one another story.

Betov.

< http://betov.free.fr/RosAsm.html >