The Simplest Example of Using the Timer

The first example to consider is the simplest example of a timer. The timer counts 10 ticks , then closes the window and displays the message box informing the user about the program termination. This program illustrates timer organization on the basis of the window function.

Listing 14.1: The simplest timer

 // The TIMER.RC file // Constants #define WS_SYSMENU         0x00080000L #define WS_MINIMIZEBOX     0x00020000L #define WS_MAXIMIZEBOX     0x00010000L // Style - Button #define BS_PUSHBUTTON      0x00000000L // The button must be visible #define WS_VISIBLE         0x10000000L // Center the button label #define BS_CENTER          0x00000300L // Button style #define WS_CHILD           0x40000000L // The possibility of focusing the element // using the <TAB> key #define WS_TABSTOP         0x00010000L #define DS_3DLOOK          0x0004L // Dialog box definition DIAL1 DIALOG 0, 0,  240,  120 STYLE WS_SYSMENU   WS_MINIMIZEBOX   WS_MAXIMIZEBOX  DS_3DLOOK CAPTION "An example of dialog with timer" FONT 8, "Arial" { // Button, identifier 5 CONTROL "Exit", 5, "button", BS_PUSHBUTTON I BS_CENTER   WS_CHILD  WS_VISIBLE   WS_TABSTOP, 180, 76, 50, 14 } ;  The TIMER.INC file ;  Constants ;  This message arrives when the window is  closed WM_CLOSE            equ 10h WM_INITDIALOG       equ 110h WM_COMMAND          equ 111n WM_TIMER            equ 113h ;  Prototypes of external procedures IFDEF MASM    EXTERN         ReleaseDC@8:NEAR    EXTERN         GetDC@4:NEAR    EXTERN         TextOutA@20:NEAR    EXTERN         MessageBoxA@16:NEAR    EXTERN         ExitProcess@4:NEAR    EXTERN         GetModuleHandleA@4:NEAR    EXTERN         DialogBoxParamA@20:NEAR    EXTERN         EndDialog@8:NEAR    EXTERN         SendMessageA@16:NEAR    EXTERN         SetTimer@16:NEAR    EXTERN         KillTimer@8:NEAR ELSE    EXTERN         ReleaseDC:NEAR    EXTERN         GetDC:NEAR    EXTERN         TextOutA:NEAR    EXTERN         MessageBoxA:NEAR    EXTERN         ExitProcess:NEAR    EXTERN         GetModuleHandleA:NEAR    EXTERN         DialogBoxParamA:NEAR    EXTERN         EndDialog:NEAR    EXTERN         SendMessageA:NEAR    EXTERN         SetTimer:NEAR    EXTERN         KillTimer:NEAR    ReleaseDC@8 = ReleaseDC    GetDC@4 = GetDC    TextOutA@20 = TextOutA    MessageBoxA@16  = MessageBoxA    ExitProcess@4 = ExitProcess    GetModuleHandleA@4 = GetModuleHandleA    DialogBoxParamA@20 = DialogBoxParamA    EndDialog@8 = EndDialog    SendMessageA@16 = SendMessageA    SetTimer@16 = SetTimer    KillTimer@8 = KillTimer ENDIF ;  Structures ; Message structure MSGSTRUCT STRUC       MSHWND        DD ?       MSMESSAGE     DD ?       MSWPARAM      DD ?       MSLPARAM      DD ?       MSTIME        DD ?       MSPT          DD ? MSGSTRUCT ENDS ; The TIMER.ASM file .586P ; Flat memory model .MODEL FLAT, stdcall include timer.inc ; INCLUDELIB directives for the linker IFDEF MASM ; For the LINK.EXE linker    includelib c:\masm32\lib\user32.lib    includelib c:\masm32\lib\kernel32.lib    includelib c:\masm32\lib\gdi32.lib ELSE ; For the TLINK32.EXE linker    includelib c:\tasm32\lib\import32.lib ENDIF ;------------------------------------------------ ; Data segment _DATA SEGMENT    MSG     MSGSTRUCT <?>    HINST   DD 0 ; Application descriptor    PA      DB "DIAL1", 0    COUNT   DD 0    TEXT    DB 0    CAP     DB 'Message,  0    MES     DB 'Exit by. timer',  0 _DATA ENDS ; Code segment _TEXT SEGMENT START: ; Get application descriptor    PUSH  0    CALL  GetModuleHandleA@4    MOV   [HINST], EAX ;--------------------------------    PUSH  0    PUSH  OFFSET WNDPROC    PUSH  0    PUSH  OFFSET PA    PUSH  [HINST]    CALL  DialogBoxParamA@20    CMP   EAX,  -1    JNE   KOL KOL: ;--------------------------------    PUSH  0    CALL  ExitProcess@4 ;------------------------------ ;  Window procedure ;  Position of  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_CLOSE    JNE   L1 ;  The  reaction to  the window closing L3: ; Delete  the timer    PUSH  1 ; Timer identifier    PUSH  DWORD PTR [EBP+08H]    CALL  KillTimer@8 ; Close the  dialog    PUSH  0    PUSH  DWORD PTR [EBP+08H]    CALL  EndDialog@8    JMP   FINISH L1:    CMP   DWORD PTR [EBP+0CH], WM_INITDIALOG    JNE   L5 ; The initialization takes place ; Set the timer       PUSH  0 ;  Parameter =  NULL       PUSH  1000 ;  Interval  of 1  second       PUSH  1 ;  Timer identifier       PUSH  DWORD PTR [EBP+08H]       CALL  SetTimer@16       JMP   FINISH L5:       CMP   DWORD PTR [EBP+0CH],  WM_COMMAND       JNE   L2 ; Exit button?       CMP   WORD PTR [EBP+10H],  5       JNE   FINISH       JMP   L3 L2:       CMP   DWORD PTR [EBP+0CH],  WM_TIMER        JNE   FINISH ; Time to exit?       CMP   COUNT,  9 ;  Exit without notification       JA    L3 ;  Exit through the message       JE    L4 ; The timer message has arrived ; Prepare the text       MOV   EAX, COUNT       ADD   EAX, 49       MOV   TEXT, AL ; Get the context       PUSH  DWORD PTR [EBP+08H]       CALL  GetDC@4 ; Save the context       PUSH  EAX ; Display the counter value       PUSH  1       PUSH  OFFSET TEXT       PUSH  10       PUSH  10       PUSH  EAX       CALL  TextOutA@20 ; Delete the context       POP  EAX       PUSH  EAX       PUSH  DWORD PTR [EBP+08H]       CALL  ReleaseDC@8 ; Increase the counter       INC   COUNT       JMP   FINISH L4:       INC COUNT ; The message about exiting from the  timer       PUSH  0       PUSH  OFFSET CAP       PUSH  OFFSET MES       PUSH  DWORD PTR [EBP+08H]  ;  window descriptor       CALL  MessageBoxA@16       JMP   L3 FINISH:       POP   EDI       POP   ESI       POP   EBX       POP   EBP       MOV   EAX,  0       RET   16 WNDPROC             ENDP ;------------------------------------------ _TEXT ENDS END START 

 

Now, let me comment on the program provided in Listing 14.1. Timer organization here is simple and obvious. The only thing that can cause some difficulties is leaving the MessageBox and simultaneously closing the dialog box. Nevertheless, here everything is simple: the message is displayed when COUNT=9 , and when the next message arrives, COUNT is greater than 9, and the branch that closes the dialog is executed.

To translate this program, issue the following commands using MASM32:

 ML /c /coff /DMASM timer.asm     RC timer.re     LINK  /SUBSYSTEM:WINDOWS timer.obj  timer.res 

Issue the following commands using TASM32:

 TASM32 /ml timer.asm     BRCC32 timer.re     TLINK32 -aa timer.obj,,,,,timer.res