参数的高字和低字

我有这个简单程序的示例代码,它检查鼠标位置,写下X和Y坐标,并检查鼠标左键是否按下。

.386
.model  flat, stdcall
option  casemap :none

include     bones.inc

.code
start:
invoke  GetModuleHandle, NULL
mov hInstance, eax
invoke  InitCommonControls
invoke  DialogBoxParam, hInstance, IDD_MAIN, 0, offset DlgProc, 0
invoke  ExitProcess, eax

DlgProc proc hWin:DWORD,uMsg:DWORD,wParam:DWORD,lParam:DWORD
mov eax,uMsg

.if eax == WM_INITDIALOG

.elseif eax == WM_LBUTTONDOWN ; when left button is down
    invoke SetDlgItemText, hWin, 1001, addr Msg1
.elseif eax == WM_LBUTTONUP ; when left button is up
    invoke SetDlgItemText, hWin, 1001, addr Msg2
.elseif eax == WM_MOUSEMOVE
    xor ecx, ecx ; clear ecx register
    mov cx, WORD PTR lParam ; copy low-word of lParam to cx  <---- this is line that is bothering me
    invoke SetDlgItemInt, hWin, 1002, ecx, FALSE ; set integer in control
    xor ecx, ecx ; zerujemy rejestr ecx
    mov cx, WORD PTR lParam+2 ; copy high-word of lParam to cx <--- this line is bothering me as well
    invoke SetDlgItemInt, hWin, 1003, ecx, FALSE ; set integer in control
.elseif eax == WM_CLOSE
    invoke  EndDialog, hWin, 0
.endif

xor eax,eax
ret
DlgProc endp

end start

1) 这行到底是什么:MOV-CX,WORD-PTR-SS:[EBP+14]?

2) 那么,在我的屏幕截图中,如果EBP值是(0001 1001 1111 1011 1011 0000)(19FBB0h)是低字(0000 0000 0001 1001)和高字(1111 1011 1011 0000)?如果不是,我该怎么学习?

4) 为什么选择mov cx,文字PTR LPRAM+2?这个+2困扰着我。如果lParam是DWORD(32位),为什么偏移量是+2?是否应该是+16才能获得高单词?

提前谢谢你

include     windows.inc
include     user32.inc
include     kernel32.inc
include     comctl32.inc    ;windows common controls

includelib  user32.lib
includelib  kernel32.lib
includelib  comctl32.lib    ;windows common controls

DlgProc     PROTO   :DWORD,:DWORD,:DWORD,:DWORD

.const
IDD_MAIN    equ 1000

.data
Msg1 db "Lewy przycisk myszy jest wciśnięty",0
Msg2 db "Lewy przycisk myszy jest zwolniony",0

.data?
hInstance   dd  ?