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i have this code, i understand alot of asm, but am still not getting a few things, in the following code:



; -------------------------------------------
      .486
      .model flat, stdcall
      option casemap :none
      include \masm32\include\windows.inc
      include \masm32\include\gdi32.inc
      include \masm32\include\user32.inc
      include \masm32\include\kernel32.inc
      includelib \masm32\lib\gdi32.lib
      includelib \masm32\lib\user32.lib
      includelib \masm32\lib\kernel32.lib
; -------------------------------------------

GetDrives    PROTO

; -------------------------------------------

.data

exts DB "txt"
Ram DB "Ram Drive",0
HDD DB "Hard Drive",0
CD DB "CDRom Drive",0
Net DB "Network Drive",0
Rem DB "Floppy/Removable Drive",0
Unk DB "Unknown Drive",0

DriveFmt db "%s = %s",0

.data?

buffer db 256 dup(?)

; -------------------------------------------

.code

START:

INVOKE GetDrives
INVOKE ExitProcess,0

GetDrives PROC
    LOCAL DRIVES[106]:BYTE
    INVOKE GetLogicalDriveStrings, sizeof DRIVES, ADDR DRIVES
    lea esi, DRIVES
    mov ecx,eax ; ECX = LENGTH OF THE STRING
    .WHILE ecx > 0 ; Scan (DRIVES)
        lea ebx,
        push ecx ; GetDriveType modifies ECX
        INVOKE GetDriveType, ebx ; drive type
        .IF eax  == DRIVE_FIXED
          INVOKE wsprintf,addr buffer,addr DriveFmt,esi,addr HDD
          invoke MessageBox,0,addr buffer,esi,0
        .ELSEIF eax  == DRIVE_CDROM
            INVOKE wsprintf,addr buffer,addr DriveFmt,esi,addr CD 
            invoke MessageBox,0,addr buffer,esi,0
        .ELSEIF eax  == DRIVE_RAMDISK
            INVOKE wsprintf,addr buffer,addr DriveFmt,esi,addr Ram
            invoke MessageBox,0,edi,addr buffer,0
        .ELSEIF eax  == DRIVE_REMOTE
            INVOKE wsprintf,addr buffer,addr DriveFmt,esi,addr  Net
            invoke MessageBox,0,addr buffer,esi,0
        .ELSEIF eax  == DRIVE_REMOVABLE
            INVOKE wsprintf,addr buffer,addr DriveFmt,esi,addr  Rem
            invoke MessageBox,0,addr buffer,esi,0
        .ELSE  ;its a unknown drive
            INVOKE wsprintf,addr buffer,addr DriveFmt,esi,addr  Unk
            invoke MessageBox,0,addr buffer,esi,0
        .ENDIF
        pop ecx ; revive ecx
        add esi, 4
        sub ecx, 4
    .ENDW
    ret
GetDrives endp
END START

-------------------------------------------


1.) buffer db 256 dup(?) - why a buffer variable, and why is it not initializaed?
2.) DriveFmt db "%s = %s",0 - this reminds me of python, but i still dont seem to get what this does? its not in my masm reference
3.) INVOKE wsprintf,addr buffer,addr DriveFmt,esi,addr  Rem - how does wsprintf work? why do i need a buffer once again, and what is addr?

thanks in advance. i've read a good manual and a couple tutorials but i still dont grasp a few things