1. Win32 windows programming
Chapter 11
Win32 windows programming

2. The chapter introduces a subset of the Win 32 API functions
You can find out more by visiting Help in VC++
Or MSDN website
There are predefined constants
Two sets of chars available: old 8-bit ASCII or 16 bit Unicode via writeConsoleA or writeConsoleW functions.

3. High/low level access available
High level access read or write to screen buffer
Low level functions can access mouse and kbd events

4. smallWin.inc
A file created by Irvine includes many constant definitions, text equates and function prototypes for win32 API programming
Included automatically in 32 bit asm

5. Some things in smallwin
The structures COORD and SYSTIME we looked at in chapter 10
Definition for HANDLE (file handle) as a DWORD
Console handles are predefined
GetSTDHandle returns a handle to an input, output or error output

6. Win32 console functions Text pg 424-425
Functions like readConsoleInput, GetConsoleMode, GetSTDHandle, etc

7. readconsole Example pg 431-432
A convenient way to read text input and store in a buffer

8. ReadConsole : run Assembling: ReadConsole.asm
Volume in drive C has no label.
Volume Serial Number is 07D2-0208
Directory of C:\masm615\examples\CH11
01/20/ :23 PM ReadConsole.asm
11/26/ :19 PM ,177 ReadConsole.obj
11/26/ :19 PM ,364 ReadConsole.lst
11/26/ :19 PM ,352 ReadConsole.ilk
11/26/ :19 PM ,729 ReadConsole.exe
11/26/ :19 PM ,136 ReadConsole.pdb
11/26/ :19 PM ,948 ReadConsole.map
7 File(s) ,320 bytes
0 Dir(s) 4,048,109,568 bytes free
Press any key to continue . . .
C:\MASM615\EXAMPLES\CH11>readconsole
123abc
Dump of offset
D 0A

9. ReadConsole : code INCLUDE Irvine32.inc BufSize = 80 .data
buffer BYTE BufSize DUP(?),0,0
stdInHandle DWORD ?
bytesRead DWORD ?
.code
main PROC
; Get handle to standard input
INVOKE GetStdHandle, STD_INPUT_HANDLE
mov stdInHandle,eax
; Wait for user input
INVOKE ReadConsole, stdInHandle, ADDR buffer,
BufSize - 2, ADDR bytesRead, 0
; Display the buffer
mov esi,OFFSET buffer
mov ecx,16 ; 16 bytes
mov ebx,TYPE buffer
call DumpMem
exit
main ENDP
END main

10. Running readconsole
Running Application with parameters: W:\assembly\irvinecd\content\Examples\ch11 ReadConsole.exe xyz Dump of offset A 0D 0A Press any key to continue . . .

11. Console1 pg 436
Writing a string to console

12. Console1: run Assembling: console1.asm Volume in drive C has no label.
Volume Serial Number is 07D2-0208
Directory of C:\masm615\examples\CH11
01/20/ :40 PM ,170 Console1.asm
11/26/ :26 PM ,255 console1.obj
11/26/ :26 PM ,927 console1.lst
11/26/ :26 PM ,536 console1.ilk
11/26/ :26 PM ,726 console1.exe
11/26/ :26 PM ,560 console1.pdb
11/26/ :26 PM ,610 console1.map
7 File(s) ,784 bytes
0 Dir(s) 4,043,505,664 bytes free
Press any key to continue . . .
C:\MASM615\EXAMPLES\CH11>console1
Console1.asm
This program is a simple demonstration of console
mode output, using the GetStdHandle and WriteConsole
functions.
C:\MASM615\EXAMPLES\CH11>

13. Console1: code INCLUDE Irvine32.inc .data
endl EQU <0dh,0ah> ; end of line sequence
message \
BYTE " Console1.asm "
BYTE endl,endl
BYTE "This program is a simple demonstration of console ",endl
BYTE "mode output, using the GetStdHandle and WriteConsole ",endl
BYTE "functions.",endl
BYTE " "
BYTE endl,endl,endl
messageSize = ($-message)
consoleHandle DWORD ; handle to standard output device
bytesWritten DWORD ? ; number of bytes written
.code
main PROC
; Get the console output handle:
INVOKE GetStdHandle, STD_OUTPUT_HANDLE
mov consoleHandle,eax
; Write a string to the console:
INVOKE WriteConsole,
consoleHandle, ; console output handle
ADDR message, ; string pointer
messageSize, ; string length
ADDR bytesWritten, ; returns num bytes written
0 ; not used
INVOKE ExitProcess,0
main ENDP
END main

14. Run of console1.asm

15. Console2.asm positions cursor
TITLE Console Demo #2 (Console2.asm) ; Demonstration of SetConsoleCursorPosition, ; GetConsoleCursorInfo, SetConsoleCursorInfo, ; SetConsoleScreenBufferSize, SetConsoleCursorPosition, ; SetConsoleTitle, and GetConsoleScreenBufferInfo. ; Last update: 9/28/01 INCLUDE SmallWin.inc .data outHandle DWORD ? scrSize COORD <120,50> xyPos COORD <20,5> consoleInfo CONSOLE_SCREEN_BUFFER_INFO <> cursorInfo CONSOLE_CURSOR_INFO <> titleStr BYTE "Console2 Demo Program",0

16. Console2 continued
.code main PROC ; Get Console output handle. INVOKE GetStdHandle,STD_OUTPUT_HANDLE mov outHandle,eax ; Get console cursor information. INVOKE GetConsoleCursorInfo, outHandle, ADDR cursorInfo ; Set console cursor size to 75% mov cursorInfo.dwSize,75 INVOKE SetConsoleCursorInfo, outHandle, ; Set the screen buffer size. INVOKE SetConsoleScreenBufferSize, outHandle,scrSize

17. And a bit more
; Set the cursor position to (20,5). INVOKE SetConsoleCursorPosition, outHandle, xyPos ; Set the console window's title. INVOKE SetConsoleTitle, ADDR titleStr ; Get screen buffer & window size information. INVOKE GetConsoleScreenBufferInfo, outHandle, ADDR consoleInfo INVOKE ExitProcess,0 main ENDP END main

19. Wrapping api functions
Irvine32.Inc file contains wrappers for file i/o (also covered in chpt 5)
On pg 442 text provides source code for these wrapper functions:
createOutputFile
OpenFile
WriteToFile
ReadFromFile
CloseFile

20. ReadFile
Code on pg 445
Just opens file created by writefile example and displays contents

21. Readfile: run…displays contents of file from writefile.asm

22. Readfile: code INCLUDE Irvine32.inc .data buffer BYTE 500 DUP(?)
bufSize = ($-buffer)
errMsg BYTE "Cannot open file",0dh,0ah,0
filename BYTE "output.txt",0
fileHandle DWORD ? ; handle to output file
byteCount DWORD ? ; number of bytes written
.code
main PROC
INVOKE CreateFile,
ADDR filename, GENERIC_READ, DO_NOT_SHARE, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0
mov fileHandle,eax ; save file handle
.IF eax == INVALID_HANDLE_VALUE
mov edx,OFFSET errMsg ; Display error message
call WriteString
jmp QuitNow
.ENDIF

23. Readfile: code INVOKE ReadFile, ; write text to file
fileHandle, ; file handle
ADDR buffer, ; buffer pointer
bufSize, ; number of bytes to write
ADDR byteCount, ; number of bytes written
0 ; overlapped execution flag
INVOKE CloseHandle, fileHandle
mov esi,byteCount ; insert null terminator
mov buffer[esi],0 ; into buffer
mov edx,OFFSET buffer ; display the buffer
call WriteString
QuitNow:
exit
main ENDP
END main

24. Writefile: run (no output) & file contents
C:\MASM615\EXAMPLES\CH11>writefile
C:\MASM615\EXAMPLES\CH11>type output.txt
This text is written to an output file.
Each run will create file and put text in the file.

25. Writefile: code INCLUDE Irvine32.inc .data
buffer BYTE "This text is written to an output file.",0dh,0ah;;;;here is text to write
bufSize = ($-buffer)
errMsg BYTE "Cannot create file",0dh,0ah,0
filename BYTE "output.txt",0 ;;;;name of output file
fileHandle DWORD ? ; handle to output file
bytesWritten DWORD ? ; number of bytes written
.code
main PROC
INVOKE CreateFile,
ADDR filename, GENERIC_WRITE, DO_NOT_SHARE, NULL,
CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0
mov fileHandle,eax ; save file handle
.IF eax == INVALID_HANDLE_VALUE
mov edx,OFFSET errMsg ; Display error message
call WriteString
jmp QuitNow
.ENDIF
INVOKE WriteFile, ; write text to file
fileHandle, ; file handle
ADDR buffer, ; buffer pointer
bufSize, ; number of bytes to write
ADDR bytesWritten, ; number of bytes written
0 ; overlapped execution flag
INVOKE CloseHandle, fileHandle
QuitNow:
exit
main ENDP
END main

26. Appendfile.asm is similar, but appends text to an existing file
TITLE Appending to a File (AppendFile.asm) ; This program appends text to an existing file. ; Last update: 1/30/02 INCLUDE Irvine32.inc .data buffer BYTE "This text is appended to an output file.",0dh,0ah bufSize = ($-buffer) errMsg BYTE "Cannot open file",0dh,0ah,0 filename BYTE "output.txt",0 fileHandle DWORD ? ; handle to output file bytesWritten DWORD ? ; number of bytes written

27. Appendfile.asm code
.code main PROC INVOKE CreateFile, ADDR filename, GENERIC_WRITE, DO_NOT_SHARE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0 mov fileHandle,eax ; save file handle .IF eax == INVALID_HANDLE_VALUE mov edx,OFFSET errMsg ; Display error message call WriteString jmp QuitNow .ENDIF ; Move the file pointer to the end of the file INVOKE SetFilePointer, fileHandle,0,0,FILE_END ; Append text to the file INVOKE WriteFile, fileHandle, ADDR buffer, bufSize, ADDR bytesWritten, 0 INVOKE CloseHandle, fileHandle QuitNow: exit main ENDP END main

28. Scroll: writes 50 lines (and console window scrolls)
C:\MASM615\EXAMPLES\CH11>scroll
0: This line of text was written to the screen buffer
1: This line of text was written to the screen buffer
2: This line of text was written to the screen buffer
3: This line of text was written to the screen buffer
4: This line of text was written to the screen buffer
5: This line of text was written to the screen buffer
6: This line of text was written to the screen buffer
7: This line of text was written to the screen buffer
8: This line of text was written to the screen buffer
9: This line of text was written to the screen buffer
10: This line of text was written to the screen buffer
11: This line of text was written to the screen buffer
12: This line of text was written to the screen buffer
13: This line of text was written to the screen buffer
14: This line of text was written to the screen buffer
15: This line of text was written to the screen buffer
16: This line of text was written to the screen buffer
17: This line of text was written to the screen buffer
18: This line of text was written to the screen buffer
19: This line of text was written to the screen buffer
20: This line of text was written to the screen buffer
21: This line of text was written to the screen buffer
22: This line of text was written to the screen buffer
23: This line of text was written to the screen buffer
24: This line of text was written to the screen buffer
25: This line of text was written to the screen buffer
26: This line of text was written to the screen buffer
27: This line of text was written to the screen buffer
28: This line of text was written to the screen buffer
29: This line of text was written to the screen buffer

29. Scroll: example from text pg 449: write 50 lines of text to screen buffer
INCLUDE Irvine32.inc
.data
message BYTE ": This line of text was written "
BYTE "to the screen buffer",0dh,0ah
messageSize = ($-message)
outHandle DWORD ; standard output handle
bytesWritten DWORD ? ; number of bytes written
lineNum DWORD 0
windowRect SMALL_RECT <0,0,60,11> ; left,top,right,bottom
.code
main PROC
INVOKE GetStdHandle, STD_OUTPUT_HANDLE
mov outHandle,eax
.REPEAT
mov eax,lineNum
call WriteDec ; display each line number
INVOKE WriteConsole,
outHandle, ; console output handle
ADDR message, ; string pointer
messageSize, ; string length
ADDR bytesWritten, ; returns num bytes written
0 ; not used
inc lineNum ; next line number
.UNTIL lineNum > 50

30. scroll ; Resize and reposition the console window relative to the
; screen buffer.
INVOKE SetConsoleWindowInfo,
outHandle,
TRUE,
ADDR windowRect
call Readchar ; wait for a key
call Clrscr ; clear the screen buffer
call Readchar ; wait for a second key
INVOKE ExitProcess,0
main ENDP
END main

31. Write colors
Text pg 452
Create an array of chars and an array of attributes (one for each char)
It calls writeconsoleattribute to put attributes on screenbuffer
It calls writeconsolecharacter to copy the characters to the same screen buffer cells

32. Writecolors INCLUDE Irvine32.inc .data outHandle DWORD ?
cellsWritten DWORD ?
xyPos COORD <10,2>
; Array of character codes:
buffer BYTE 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
BYTE 16,17,18,19.20
BufSize = ($ - buffer)
; Array of attributes:
attributes WORD 0Fh,0Eh,0Dh,0Ch,0Bh,0Ah,9,8,7,6
WORD 5,4,3,2,1,0F0h,0E0h,0D0h,0C0h,0B0h
.code
main PROC
; Get the Console standard output handle:
INVOKE GetStdHandle,STD_OUTPUT_HANDLE
mov outHandle,eax
; Set the colors from (10,2) to (30,2):
INVOKE WriteConsoleOutputAttribute,
outHandle, ADDR attributes,
BufSize, xyPos,
ADDR cellsWritten
; Write character codes 1 to 20:
INVOKE WriteConsoleOutputCharacter,
outHandle, ADDR buffer, BufSize,
xyPos, ADDR cellsWritten
call ReadChar
exit
main ENDP
END main

33. writecolors

34. TimingLoop just prints dots (slowly)
INCLUDE Irvine32.inc
TIME_LIMIT = 5000
.data
startTime DWORD ?
dot BYTE ".",0
.code
main PROC
INVOKE GetTickCount
mov startTime,eax
L1:
mov edx,OFFSET dot ; display a dot
call WriteString
INVOKE Sleep,100 ; sleep for 100ms
sub eax,startTime ; check the elapsed time
cmp eax,TIME_LIMIT
jb L1
L2: exit
main ENDP
END main

35. Timingloop counts elapsed time before keypress
C:\MASM615\EXAMPLES\CH11>timer
5000 milliseconds have elapsed

36. Timer.asm
Text pg
A stopwatch program gets elapsed time between two calls to tickcount

37. timer INCLUDE Irvine32.inc TimerStart PROTO, pSavedTime: PTR DWORD
TimerStop PROTO,
.data
msg BYTE " milliseconds have elapsed",0dh,0ah,0
timer1 DWORD ?
.code
main PROC
INVOKE TimerStart, ; start the timer
ADDR timer1
INVOKE Sleep, 5000 ; sleep for a while
INVOKE TimerStop, ; EAX = elapsed milliseconds
call WriteDec ; display elapsed time
mov edx,OFFSET msg
call WriteString
exit
main ENDP

38. timer ;--------------------------------------------------
TimerStart PROC uses eax esi,
pSavedTime: PTR DWORD
; Starts a stopwatch timer.
; Receives: pointer to a variable that will hold
; the current time.
; Returns: nothing
INVOKE GetTickCount
mov esi,pSavedTime
mov [esi],eax
ret
TimerStart ENDP
TimerStop PROC uses esi, ;
; Stops the current stopwatch timer.
; Receives: pointer to a variable holding the
; saved time
; Returns: EAX = number of elapsed milliseconds
; Remarks: Accurate to about 10ms
mov esi,pSavedTime
sub eax,[esi]
TimerStop ENDP
END main

39. Running timer

40. winApp.asm text pg 461 Display text in a pop up messagebox
About winMain
Every windows app needs a startup proc typically named WinMain which
Gets handle to current program
Loads program icon and mouse cursor
Creates main window
Show/update window
Loops to receive and dspatch messages

41. A windows app

42. A windows app

43. A windows app

44. Winapp data area INCLUDE Irvine32.inc INCLUDE GraphWin.inc
AppLoadMsgTitle BYTE "Application Loaded",0
AppLoadMsgText BYTE "This window displays when the WM_CREATE "
BYTE "message is received",0
PopupTitle BYTE "Popup Window",0
PopupText BYTE "This window was activated by a "
BYTE "WM_LBUTTONDOWN message",0
GreetTitle BYTE "Main Window Active",0
GreetText BYTE "This window is shown immediately after "
BYTE "CreateWindow and UpdateWindow are called.",0
CloseMsg BYTE "WM_CLOSE message received",0
ErrorTitle BYTE "Error",0
WindowName BYTE "ASM Windows App",0
className BYTE "ASMWin",0
; Define the Application's Window class structure.
MainWin WNDCLASS <NULL,WinProc,NULL,NULL,NULL,NULL,NULL, \
COLOR_WINDOW,NULL,className>
msg MSGStruct <>
winRect RECT <>
hMainWnd DWORD ?
hInstance DWORD ?

45. Winapp code-4 slides
;=================== CODE =========================
.code
WinMain PROC
; Get a handle to the current process.
INVOKE GetModuleHandle, NULL
mov hInstance, eax
mov MainWin.hInstance, eax
; Load the program's icon and cursor.
INVOKE LoadIcon, NULL, IDI_APPLICATION
mov MainWin.hIcon, eax
INVOKE LoadCursor, NULL, IDC_ARROW
mov MainWin.hCursor, eax
; Register the window class.
INVOKE RegisterClass, ADDR MainWin
.IF eax == 0
call ErrorHandler
jmp Exit_Program
.ENDIF

46. Winapp code ; Create the application's main window.
; Returns a handle to the main window in EAX.
INVOKE CreateWindowEx, 0, ADDR className,
ADDR WindowName,MAIN_WINDOW_STYLE,
CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,
CW_USEDEFAULT,NULL,NULL,hInstance,NULL
mov hMainWnd,eax
; If CreateWindowEx failed, display a message & exit.
.IF eax == 0
call ErrorHandler
jmp Exit_Program
.ENDIF
; Show and draw the window.
INVOKE ShowWindow, hMainWnd, SW_SHOW
INVOKE UpdateWindow, hMainWnd
; Display a greeting message.
INVOKE MessageBox, hMainWnd, ADDR GreetText,
ADDR GreetTitle, MB_OK
; Begin the program's message-handling loop.
Message_Loop:
; Get next message from the queue.
INVOKE GetMessage, ADDR msg, NULL,NULL,NULL
; Quit if no more messages.
jmp Exit_Program
; Relay the message to the program's WinProc.
INVOKE DispatchMessage, ADDR msg
jmp Message_Loop
Exit_Program:
INVOKE ExitProcess,0
WinMain ENDP

47. Winapp code ;-----------------------------------------------------
WinProc PROC,
hWnd:DWORD, localMsg:DWORD, wParam:DWORD, lParam:DWORD
; The application's message handler, which handles
; application-specific messages. All other messages
; are forwarded to the default Windows message
; handler.
mov eax, localMsg
.IF eax == WM_LBUTTONDOWN ; mouse button?
INVOKE MessageBox, hWnd, ADDR PopupText,
ADDR PopupTitle, MB_OK
jmp WinProcExit
.ELSEIF eax == WM_CREATE ; create window?
INVOKE MessageBox, hWnd, ADDR AppLoadMsgText,
ADDR AppLoadMsgTitle, MB_OK
.ELSEIF eax == WM_CLOSE ; close window?
INVOKE MessageBox, hWnd, ADDR CloseMsg,
ADDR WindowName, MB_OK
INVOKE PostQuitMessage,0
.ELSE ; other message?
INVOKE DefWindowProc, hWnd, localMsg, wParam, lParam
.ENDIF
WinProcExit:
ret
WinProc ENDP

48. Winapp code ;---------------------------------------------------
ErrorHandler PROC
; Display the appropriate system error message.
.data
pErrorMsg DWORD ? ; ptr to error message
messageID DWORD ?
.code
INVOKE GetLastError ; Returns message ID in EAX
mov messageID,eax
; Get the corresponding message string.
INVOKE FormatMessage, FORMAT_MESSAGE_ALLOCATE_BUFFER + \
FORMAT_MESSAGE_FROM_SYSTEM,NULL,messageID,NULL,
ADDR pErrorMsg,NULL,NULL
; Display the error message.
INVOKE MessageBox,NULL, pErrorMsg, ADDR ErrorTitle,
MB_ICONERROR+MB_OK
; Free the error message string.
INVOKE LocalFree, pErrorMsg
ret
ErrorHandler ENDP
END WinMain

49. ReadFile
Code on pg 445
Just opens file created by writefile example and displays contents

50. Readfile: run…displays contents of file from writefile.asm

51. Readfile: code INCLUDE Irvine32.inc .data buffer BYTE 500 DUP(?)
bufSize = ($-buffer)
errMsg BYTE "Cannot open file",0dh,0ah,0
filename BYTE "output.txt",0
fileHandle DWORD ? ; handle to output file
byteCount DWORD ? ; number of bytes written
.code
main PROC
INVOKE CreateFile,
ADDR filename, GENERIC_READ, DO_NOT_SHARE, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0
mov fileHandle,eax ; save file handle
.IF eax == INVALID_HANDLE_VALUE
mov edx,OFFSET errMsg ; Display error message
call WriteString
jmp QuitNow
.ENDIF

52. Readfile: code INVOKE ReadFile, ; write text to file
fileHandle, ; file handle
ADDR buffer, ; buffer pointer
bufSize, ; number of bytes to write
ADDR byteCount, ; number of bytes written
0 ; overlapped execution flag
INVOKE CloseHandle, fileHandle
mov esi,byteCount ; insert null terminator
mov buffer[esi],0 ; into buffer
mov edx,OFFSET buffer ; display the buffer
call WriteString
QuitNow:
exit
main ENDP
END main

53. The Heap
Objects are created off the heap (dynamic mem allocation) not the stack
Functions:
You can get the process heap – default heap owned by current program
Heap destroy
Heap alloc

54. Heaptest1
Creates and fills a 1000-byte array

55. Heap test… allocating heap space
Title Heap Test #1 (Heaptest1.asm) INCLUDE Irvine32.inc ; This program uses dynamic memory allocation to allocate and ; fill an array of bytes. .data ARRAY_SIZE = 1000 FILL_VAL EQU 0FFh hHeap DWORD ? ; handle to the process heap pArray DWORD ? ; pointer to block of memory newHeap DWORD ? ; handle to new heap str1 BYTE "Heap size is: ",0

56. Heap test… allocating heap space
.code
main PROC
INVOKE GetProcessHeap ; get handle to prog's heap
.IF eax == NULL ; failed?
;call WriteWindowsMsg
jmp quit
.ELSE
mov hHeap,eax ; success
.ENDIF
call allocate_array
jnc arrayOk ; failed (CF = 1)?
call Crlf
arrayOk: ; ok to fill the array
call fill_array
call display_array
; free the array
INVOKE HeapFree, hHeap, 0, pArray
quit:
exit
main ENDP ;
allocate_array PROC USES eax ;
; Dynamically allocates space for the array.
; Receives: nothing
; Returns: CF = 0 if allocation succeeds.
INVOKE HeapAlloc, hHeap, HEAP_ZERO_MEMORY, ARRAY_SIZE
.IF eax == NULL
stc ; return with CF = 1
mov pArray,eax ; save the pointer
clc ; return with CF = 0
ret
allocate_array ENDP
fill_array PROC USES ecx edx esi
; Fills all array positions with a single character.
; Returns: nothing
mov ecx,ARRAY_SIZE ; loop counter
mov esi,pArray ; point to the array
L1: mov BYTE PTR [esi],FILL_VAL ; fill each byte
inc esi ; next location
loop L1
fill_array ENDP

57. And more
; display_array PROC USES eax ebx ecx esi ; ; Displays the array ; Receives: nothing ; Returns: nothing mov ecx,ARRAY_SIZE ; loop counter mov esi,pArray ; point to the array L1: mov al,[esi] ; get a byte mov ebx,TYPE BYTE call WriteHexB ; display it inc esi ; next location loop L1 ret display_array ENDP END main

58. Had to Comment off call to writewindowmsg

59. Heaptest 2 code not show…request blocks until no more available