虚拟8086模式的内存管理

例子：

这个例子演示了API传送方式，使用了int 21h的440Dh功能（从代码66h）。这个中断调用得到媒体ID，你的第一个固定磁盘的卷标号。

;---------------------------------------------------------------
; VxDLabel.asm
;---------------------------------------------------------------
.386p
include \masm\include\vmm.inc
include \masm\include\vwin32.inc
include \masm\include\v86mmgr.inc
VxDName TEXTEQU
ControlName TEXTEQU
VxDMajorVersion TEXTEQU <1>
VxDMinorVersion TEXTEQU <0>

VxD_STATIC_DATA_SEG
VxD_STATIC_DATA_ENDS

VXD_LOCKED_CODE_SEG
;----------------------------------------------------------------------------
; Remember: The name of the vxd MUST be uppercase else it won't work/unload
;----------------------------------------------------------------------------
DECLARE_VIRTUAL_DEVICE %VxDName,%VxDMajorVersion,%VxDMinorVersion, %ControlName,UNDEFINED_DEVICE_ID,UNDEFINED_INIT_ORDER

Begin_control_dispatch %VxDName
Control_Dispatch W32_DEVICEIOCONTROL, OnDeviceIoControl
End_control_dispatch %VxDName

VXD_LOCKED_CODE_ENDS

VXD_PAGEABLE_CODE_SEG
BeginProc OnDeviceIoControl
assume esi:ptr DIOCParams
.if [esi].dwIoControlCode==1
VMMCall Get_Sys_VM_Handle
mov Handle,ebx
assume ebx:ptr cb_s
mov ebp,[ebx+CB_Client_Pointer]
mov ecx,sizeof MID
stc
push esi
mov esi,OFFSET32 MediaID
push ds
pop fs
VxDCall V86MMGR_Allocate_Buffer
pop esi
jc EndI
mov AllocSize,ecx
Push_Client_State
VMMCall Begin_Nest_V86_Exec
assume ebp:ptr Client_Byte_Reg_Struc
mov [ebp].Client_ch,8
mov [ebp].Client_cl,66h
assume ebp:ptr Client_word_reg_struc
mov edx,edi
mov [ebp].Client_bx,3 ; drive A
mov [ebp].Client_ax,440dh
mov [ebp].Client_dx,dx
shr edx,16
mov [ebp].Client_ds,dx
mov eax,21h
VMMCall Exec_Int
VMMCall End_Nest_Exec
Pop_Client_State
;-------------------------------
; retrieve the data
;-------------------------------
mov ecx,AllocSize
stc
mov ebx,Handle
push esi
mov esi,OFFSET32 MediaID
push ds
pop fs
VxDCall V86MMGR_Free_Buffer
pop esi
mov edx,esi
assume edx:ptr DIOCParams
mov edi,[edx].lpvOutBuffer
mov esi,OFFSET32 MediaID.midVolLabel
mov ecx,11
rep movsb
mov byte ptr [edi],0
mov ecx,[edx].lpcbBytesReturned
mov dword ptr [edx],11
EndI:
.endif
xor eax,eax
ret
EndProc OnDeviceIoControl
VXD_PAGEABLE_CODE_ENDS

VXD_PAGEABLE_DATA_SEG
MID struct
midInfoLevel dw 0
midSerialNum dd ?
midVolLabel db 11 dup(?)
midFileSysType db 8 dup(?)
MID ends
MediaID MID <>
Handle dd ?
AllocSize dd ?
VXD_PAGEABLE_DATA_ENDS

end

;------------------------------------------------------------
; Label.asm
; The win32 VxD loader.
;------------------------------------------------------------
.386
.model flat,stdcall
option casemap:none

include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib

DlgProc PROTO :DWORD,:DWORD,:DWORD,:DWORD
.data
Failure db "Cannot load VxDLabel.VXD",0
AppName db "Get Disk Label",0
VxDName db "\\.\vxdLabel.vxd",0
OutputTemplate db "Volume Label of Drive C",0

.data?
hInstance HINSTANCE ?
hVxD dd ?
DiskLabel db 12 dup(?)
BytesReturned dd ?

.const
IDD_VXDRUN equ 101
IDC_LOAD equ 1000

.code
start:
invoke GetModuleHandle, NULL
mov hInstance,eax
invoke DialogBoxParam, hInstance, IDD_VXDRUN ,NULL,addr DlgProc,NULL
invoke ExitProcess,eax

DlgProc proc hDlg:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM
.IF uMsg==WM_INITDIALOG
invoke CreateFile,addr VxDName,0,0,0,0,FILE_FLAG_DELETE_ON_CLOSE,0
.if eax==INVALID_HANDLE_VALUE
invoke MessageBox,hDlg,addr Failure,addr AppName,MB_OK+MB_ICONERROR
mov hVxD,0
invoke EndDialog,hDlg,NULL
.else
mov hVxD,eax
.endif
.elseif uMsg==WM_CLOSE
.if hVxD!=0
invoke CloseHandle,hVxD
.endif
invoke EndDialog,hDlg,0
.ELSEIF uMsg==WM_COMMAND
mov eax,wParam
mov edx,wParam
shr edx,16
.if dx==BN_CLICKED
.IF ax==IDC_LOAD
invoke DeviceIoControl,hVxD,1,NULL,0,addr DiskLabel,12,addr BytesReturned,NULL
invoke MessageBox,hDlg,addr DiskLabel,addr OutputTemplate,MB_OK+MB_ICONINFORMATION
.endif
.endif
.ELSE
mov eax,FALSE
ret
.ENDIF
mov eax,TRUE
ret
DlgProc endp
end start