format PE64 GUI 6.0
entry start

include 'win64a.inc'

section '.code' code readable executable

proc start

        invoke GetModuleHandleW,0
        mov [wc.hInstance],rax

        mov [wc.cbSize],sizeof.WNDCLASSEX

        mov [wc.style],CS_HREDRAW or CS_VREDRAW
        mov [wc.lpfnWndProc],WindowProc
        mov [wc.cbClsExtra],0

        invoke LoadIcon,0,IDI_APPLICATION
        mov [wc.hIcon],rax
        mov [wc.hIconSm],rax

        invoke LoadCursor,0,IDC_ARROW
        mov [wc.hCursor],rax

        mov [wc.hbrBackground],COLOR_WINDOW+1
        mov [wc.lpszMenuName],NULL
        mov [wc.lpszClassName],szClass

        invoke RegisterClass,wc

        invoke CreateWindowEx,0,szClass,szTitle,WS_VISIBLE + WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,500,100,NULL,NULL,[wc.hInstance],NULL
        mov [hWnd],rax

  msg_loop:
        invoke  GetMessage,msg,NULL,0,0
        or      eax,eax
        je      exit
        jne     msg_loop

        invoke  TranslateMessage,msg
        invoke  DispatchMessage,msg
        jmp     msg_loop

  exit:

        invoke ExitProcess,[msg.wParam]

endp

proc WindowProc hwnd,wmsg,wparam,lparam

        mov [hwnd],rcx
        mov [wmsg],rdx
        mov [wparam],r8
        mov [lparam],r9

        cmp [wmsg],WM_DESTROY
        jne .defwndproc

        invoke PostQuitMessage,0

        ret

    .defwndproc:

        invoke DefWindowProc,[hwnd],[wmsg],[wparam],[lparam]
        ret
endp


section '.data' data readable writeable

        hWnd dq ?
        hInstance dq ?

        szTitle db 'CLOCK',0
        szClass db 'CLOCK',0

wc WNDCLASSEX
msg MSG

section '.idata' import data readable writeable

  library kernel,'KERNEL32.DLL',\
          user,'USER32.DLL'

  import kernel,\
         ExitProcess,'ExitProcess',\
         GetModuleHandleW,'GetModuleHandleW',\
         Sleep,'Sleep'

  import user,\
  PostQuitMessage,'PostQuitMessage',\
         LoadIcon,'LoadIconA',\
         LoadCursor,'LoadCursorA',\
         ShowWindow,'ShowWindow',\
         RegisterClass,'RegisterClassA',\
         CreateWindowEx,'CreateWindowExA',\
         DefWindowProc,'DefWindowProcA',\
         GetMessage,'GetMessageA',\
         TranslateMessage,'TranslateMessage',\
         DispatchMessage,'DispatchMessageA'