How To Do It Using TASM32

After considering the program shown in Listing 2.2, you might ask a reasonable questionhow do I implement the same program in TASM? Only minor changes are required to achieve this: Instead of using the user32.lib and kernel32.lib libraries, it is necessary to link the import32.lib library, delete the @N suffix from all names of library procedures, and issue the following commands:

 tasm32 /ml prog.asm tlink32 -aa prog.obj 

Listing 2.3: An easy example of a Windows application (TASM32)

 :586P ; Flat memory model .MODEL FLAT, stdcall ; Constants ; Message arrives when the window is closed WM_DESTROY          equ 2 ; Message arrives when the window is created WM_CREATE           equ 1 ; Message when left-clicking the mouse in the window area WM_LBUTTONDOWN      equ 201h ; Message when right-clicking the mouse in the window area WM_RBUTTONDOWN      equ 204h ; Window properties CS_VREDRAW          equ 1h CS_HREDRAW          equ 2h CS_GLOBALCLASS      equ 4000h WS_OVERLAPPEDWINDOW equ 000CF0000H Style               equ CS_HREDRAW+CS_VREDRAW+CS_GLOBALCLASS ; Identifier of the standard icon IDI_APPLICATION     equ 32512 ; Cursor identifier IDC_CROSS           equ 32515 ; Normal mode of displaying the window SW_SHOWNORMAL       equ 1 ; Prototypes of external procedures EXTERN MessageBoxA:NEAR EXTERN CreateWindowExA:NEAR EXTERN DefWindowProcA:NEAR EXTERN DispatchMessageA:NEAR EXTERN ExitProcess:NEAR EXTERN GetMessageA:NEAR EXTERN GetModuleHandleA:NEAR EXTERN LoadCursorA:NEAR EXTERN LoadIconA:NEAR EXTERN PostQuitMessage:NEAR EXTERN RegisterClassA:NEAR EXTERN ShowWindow:NEAR EXTERN TranslateMessage:NEAR EXTERN UpdateWindow:NEAR ; Directives for the linker to link libraries includelib c:\tasm32\lib\import32.lib ;------------------------------------------ ; Structures ; Message structure MSGSTRUCT STRUC      MSHWND      DD ? ; Identifier of the window that received the message      MSMESSAGE   DD ? ; Message identifier      MSWPARAM    DD ? ; Auxiliary information about the message      MSLPARAM    DD ? ; Auxiliary information about the message      MSTIME      DD ? ; Time when the message was sent      MSPT        DD ? ; Cursor position at the time of sending the message MSGSTRUCT ENDS ;------------ WNDCLASS STRUC     CLSSTYLE           DD ? ; Window style     CLWNDPROC          DD ? ; Pointer to the window structure     CLSCEXTRA          DD ? ; Information on the auxiliary bytes                             ; for this structure     CLWNDEXTRA         DD ? ; Information on the auxiliary bytes                             ; for the window     CLSHINSTANCE       DD ? ; Application descriptor     CLSHICON           DD ? ; Window icon identifier     CLSHCURSOR         DD ? ; Window cursor identifier     CLBKGROUND         DD ? ; Window brush identifier     CLMENUNAME         DD ? ; Menu identifier     CLNAME             DD ? ; Specifies the window class name WNDCLASS ENDS ; Data segment _DATA SEGMENT     NEWHWND      DD 0     MSG          MSGSTRUCT <?>     WC           WNDCLASS <?>     HINST ;      DD 0 ; Here, the application descriptor is stored     TITLENAME    DB 'A simple example of a 32-bit application', 0     CLASSNAME    DB 'CLASS32', 0     CAP          DB 'Message', 0     MES1         DB 'You have clicked the left mouse button', 0     MES2         DB 'Exit. Bye!', 0 _DATA ENDS ; Code segment _TEXT SEGMENT START: ; Get the application descriptor     PUSH         0     CALL         GetModuleHandleA     MOV          [HINST], EAX REG_CLASS: ; Fill the window structure ; Style     MOV   [WC.CLSSTYLE], style ; Message-handling procedure     MOV   [WC.CLWNDPROC], OFFSET WNDPROC     MOV   [WC.CLSCSEXTRA], 0     MOV   [WC.CLNDEXTRA], 0     MOV   EAX, [HINST]     MOV   [WC.CLSHINSTANCE], EAX ;----------Window icon     PUSH  IDI_APPLICATION     PUSH  0     CALL  LoadIconA     MOV   [WC.CLSHICON], EAX ;---------- Window cursor     PUSH  IDC_CROSS     PUSH  0     CALL  LoadCursorA     MOV   [WC.CLSHCURSOR], EAX ;----------     MOV   [WC.CLBCKGROUND], 17 ; Window color     MOV   DWORD PTR [WC.CLMENUNAME], 0     MOV   DWORD PTR [WC.CLNAME], OFFSET CLASSNAME     PUSH  OFFSET WC     CALL  RegisterClassA ; Create the window of the registered class     PUSH  0     PUSH  [HINST]     PUSH  0     PUSH  0     PUSH  400 ; DY - Window height     PUSH  400 ; DX - Window width     PUSH  100 ; Y - Coordinate of the window's top left corner     PUSH  100 ; X - Coordinate of the window's top left corner     PUSH  WS_OVERLAPPEDWINDOW     PUSH  OFFSET TITLENAME ; Window name     PUSH  OFFSET CLASSNAME ; Window class     PUSH  0     CALL  CreateWindowExA ; Checking for errors     CMP   EAX, 0     JZ    _ERR     MOV   [NEWHWND], EAX     PUSH  SW_SHOWNORMAL     PUSH  [NEWHWND]     CALL  ShowWindow ; Show the newly-created window     PUSH  [NEWHWND]     CALL  UpdateWindow ; Redraw the visible part                        ; of the window, the WM_PAINT message ; Message-handling loop MSG_LOOP:     PUSH  0     PUSH  0     PUSH  0     PUSH  OFFSET MSG     CALL  GetMessageA     CMP   EAX, 0     JE    END_LOOP     PUSH  OFFSET MSG     CALL  TranslateMessage     PUSH  OFFSET MSG     CALL  DispatchMessageA     JMP   MSG_LOOP END_LOOP: ; Exit the program (close the process)     PUSH  [MSG.MSWPARAM]     CALL  ExitProcess _ERR:     JMP   END_LOOP ;--------------------- Window procedure ; Position of the parameters in the stack ; [EBP+014H]   LPARAM ; [EBP+10H]    WAPARAM ; [EBP+0CH]    MES ; [EBP+8]      HWND WNDPROC PROC     PUSH  EBP     MOV   EBP, ESP     PUSH: EBX     PUSH  ESI     PUSH  EDI     CMP   DWORD PTR [EBP+0CH], WM_DESTROY     JE    WMDESTROY     CMP   DWORD PTR [EBP+0CH], WM_CREATE     JE    WMCREATE     CMP   DWORD PTR [EBP+0CH], WM_LBUTTONDOWN ; Left button     JE    LBUTTON     CMP   DWORD PTR [EBP+0CH], WM_RBUTTONDOWN ; Right button     JE    RBUTTON     JMP   DEFWNDPROC ; Right-clicking the mouse closes the window RBUTTON:     JMP   WMDESTROY ; Left-clicking the mouse LBUTTON: ; Displaying the message     PUSH  0 ; MB_OK     PUSH  OFFSET CAP     PUSH  OFFSET MES1     PUSH  DWORD PTR [EBP+08H]     CALL  MessageBoxA     MOV   EAX, 0     JMP   FINISH WMCREATE:     MOV   EAX, 0     JMP   FINISH DEFWNDPROC:     PUSH  DWORD PTR [EBP+14H]     PUSH  DWORD PTR [EBP+10H]     PUSH  DWORD PTR [EBP+0CH]     PUSH  DWORD PTR [EBP+08H]     CALL  DefWindowProcA     JMP   FINISH WMDESTROY:     PUSH  0  ; MB_OK     PUSH  OFFSET CAP     PUSH  OFFSET MES2     PUSH  DWORD PTR [EBP+08H] ; Window descriptor     CALL  MessageBoxA     PUSH  0     CALL  PostQuitMessage ; WM_QUIT message     MOV   EAX, 0 FINISH:     POP   EDI     POP   ESI     POP   EBX     POP   EBP     RET 16 WNDPROC ENDP _TEXT ENDS END START 

 

By the way, note that the executable module translated using TASM32 is always longer than the similar module translated using MASM32.

Note how window properties are specified. Descriptions of these properties can be found in the help system for the CreateWindow function. Principally, the selection of the required window properties and their combinations is a tedious task. This is one of the reasons why the resources became an integral part of the executable module. The concept of resources will be covered in detail in Chapters 9 and 10.

The examples provided here show that the window procedure must correctly react to the received messages. Later, you'll discover that the window procedure itself can send messages to the application, other windows, and to its own window. ^[i]

Some API functions have the A suffix. API functions have two prototypes: the ones with the A suffix support ANSI, and the ones with the W suffix support Unicode.

^[i] PostQuit is an example illustrating a message sent to the procedure's own window.