[[seoane]]

Creo que no me explique bien, el código no debe escribirse directamente en la unit, se debe encerrar dentro de algún evento como por ejemplo hacer click sobre un botón:

Código Delphi [-]
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

type
  TBuffer = array[$0000..$FFFF] of Byte;

function Insertar(Str: String; var Buffer: TBuffer): String;
var
  i,j,k: Integer;
begin
  Result:= EmptyStr;
  Str:= Trim(Str);
  if Copy(Str,1,1) = ':' then
    if TryStrToInt('$' + Copy(Str,2,2),i) then
      if Length(Str) = ((2*i) + 11) then
        if TryStrToInt('$' + Copy(Str,4,4),j) then
          if TryStrToInt('$' + Copy(Str,8,2),k) then
            if k = 0 then
            begin
              Str:= Copy(Str,10,2*i);
              for k:= j to (j + i - 1) do
              begin
                Buffer[k]:= StrToInt('$' + Copy(Str,1,2));
                Delete(Str,1,2);
              end;
            end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  i,j: Integer;
  Str: String;
  Buffer: TBuffer;
begin
  Memo1.Clear;
  with TStringList.Create do
  try
    LoadFromFile('d:\test.hex');
    FillChar(Buffer,Sizeof(Buffer),#0);
    for i:= 0 to Count - 1 do
      Insertar(Strings[i],Buffer);
    Str:= EmptyStr;
    j:= Sizeof(Buffer) - 1;
    while (Buffer[j] = 0) and (j > 0) do
      dec(j);
    for i:= 0 to j do
    begin
      Str:= Str + #32 + IntToHex(Buffer[i],2);
      if ((i+1) mod 16 = 0) then
      begin
        Memo1.Lines.Add(Str);
        Str:= EmptyStr;
      end;
    end;
  finally
    Free;
  end;
end;

end.