.586
.model flat, stdcall
option casemap:none

include /masm32/include/windows.inc
include /masm32/include/kernel32.inc
include /masm32/include/user32.inc

includelib /masm32/lib/kernel32.lib
includelib /masm32/lib/user32.lib

WinMain proto :dword,:dword,:dword,:dword

.data
   ClassName db "WndClass",0
   AppName   db "Window!",0
.data?
   hInstance   dd ?
   CommandLine dd ?

.code
start:
   invoke GetModuleHandle, NULL
   mov hInstance, eax
   invoke GetCommandLine
   mov CommandLine, eax
   invoke WinMain, hInstance, NULL, CommandLine, SW_SHOWDEFAULT

   WinMain proc hInst:dword, hPervInst:dword, CmdLine:dword, CmdShow:dword
   LOCAL wc:WNDCLASSEX
   LOCAL msg:MSG
   LOCAL hwnd:HWND

   wc.cbSize, sizeof WNDCLASSEX
   wc.style, CS_HREDRAW or CS_VREDRAW
   wc.lpfnWndPRoc, offset WndProc
   wc.cbClsExtra,NULL
   wc.cbWndExtra, NULL
   push hInstance
   pop wc.hInstance
   mov wc.hbrBackground, COLOR_BTNFACE+1
   mov wc.lpszMenuName NULL
   mov wc.lpszClassName, offset ClassName
   invoke LoadIcon, NULL, IDI_APPLICATION
   mov wc.hIcon, eax
   mov wc.hIconSm, eax
   invoke LoadCursor, NULL, IDC_ARROW
   mov wc.hCursor, eax
   invoke RegisterClassEx, addr wc
   invoke CreateWindowEx, NULL, addr ClassName, addr AppName, WS_OVERLAPPEDWINDOW, CS_USEDEFAULT, CW_USEDEFAUT,\
   CW_USEDEFAUT, CW_USEDEFAUT, NULL, NULL, hInst, NULL
   mov hwnd, eax
   invoke ShowWindow, hwnd, SW_SHOWNORMAL
   invoke UpdateWindow, hwnd
   .while TRUE
      invoke GetMessage, addr msg, NULL, 0,0
      .break .if (!eax)
      invoke TranslateMessage, addr msg
      invoke DispatchMessage, addr msg
   .endw
   mov eax, msg.wParam
   ret
   WinMain endp

   WndProc proc hWnd:dword, uMsg:dword, wParam:dword, lParam:dword
   mov eax, uMsg
   .if eax==WM_DESTROY
      invoke PostQuitMessage, NULL
   .else
      invoke DefWindowProc, hWnd, uMsg, wParam, lParam
   .endif
   xor eax, eax
   ret
   WndProc endp
end start