depptiny.nas

Cracker终结者——提供最优秀的软件保护技术

                ret

shortmatch      call    getesi          ;Get a byte
                shr     ax,1            ;Distance = AL/2, Lenght in carry flag
                jz      donedepacking   ;If zero, end packing
                adc     cx,cx           ;Lenght = 1 or 0
                jmp     short domatch_with_2inc ; Decode with lenght 2 or 3

donedepacking   pop     esi             ;ESI=freemem32
                sub     edi,esi         ;And here finish DEPACK 16
                                        ;Now edi has the number of depacked
                                        ; bytes left to be written
                push    ds              ;Preserve data segment
                mov     ch,080h         ;Write using 32K chunks to enable
                                        ; the sign optimization
                mov     dx,freemem      ;Flush everything from here to end
more            cmp     edi,ecx
                ja      notlast         ;If EDI > 32K, write 32K bytes
                mov     cx,di           ;If EDI < 32K, write EDI bytes
notlast         call    writefile       ;Write chunk
                mov     ax,ds
                add     ah,8
                mov     ds,ax           ;Advance 32K

                sub     edi,ecx         ;Update number of bytes to be written
                ja      more            ;Above zero, continue writing
                pop     ds              ;Recover data segment
                push    ds
                pop     es              ;Set es=ds
                pop     dx              ;Get pointer to outfile name
                push    dx              ;store again
                call    close_del       ;Close temporal outfile and try to
                                        ; delete the file named with our
                                        ; outfile name, in case it exists
                jnc     renameit        ;If that file existed and was deleted,
                                        ; go ahead and rename the temporal one
                cmp     al,5            ;If it didn't exist, rename it too
                jz      finerr          ;But if error was for other reason,
                                        ; exit with NOT OK
renameit        mov     ah,56h
                pop     di              ;Outfile name
tmpname         mov     dx,notok
                call    int_n_check     ;Rename temporal outfile to outfile
                mov     dl,noerr-512    ;Final message: OK
final_dxok      mov     ah,9
                int     33              ;Show final message
                int     20h             ;Exit program

writefile       mov     bx,[ss:handletmp] ;Get temporal outfile handle
                mov     ah,40h
                call    int_n_check     ;Write
                dec     ax
                jns     not_finerr      ;If disk isn't full there's no error
finerr          mov     dx,[tmpname+1]  ;Temporal outfile will be deleted
                push    word final_dxok
close_del       mov     ah,3eh
                int     33              ;Close temporal outfile
                mov     ah,41h
                int     33              ;Delete outfile (when called to
                                        ; close_del) or temporal outfile
                mov     dl,notok-512    ;Error message: NOT OK
not_finerr      ret                     ; return or go to final_dxok

getesi          cmp     esi,[freemem32] ; If esi is at freemem32, we must
                jnz     dontread        ;load 32k of compressed data
                mov     bh,128          ;BL was 0, EBX=32K
                pushad                  ;Keep all registers (32bit because
                mov     ah,3fh          ; DOS function may modify EAX!!!)
                mov     cx,bx           ;Number of bytes
                mov     bx,[handlein]   ;Take infile handle
                mov     dx,inbuff       ;Place to read
                call    int_n_check     ;Read and exit if error
                dec     ax              ;---Test for bad infile #2: 0 bytes
                popad                   ;\/  read (a good infile will finish
                js      finerr          ;/\  and won't ask for more data)
                                        ;  >Restore registers
                sub     esi,ebx         ;esi at beginning of buffer again
dontread        push    esi             ;----->Emulates mov al,[esi] in 16 bit
                pop     bx              ;    /   code (as mov al,[esi] gives
                pop     bx              ;   /    a nasty fault)
                ror     bx,4            ;  /
                mov     es,bx           ; /
                mov     al,[es:si]      ;/
                inc     esi             ;Update read pointer
                ret

int_n_check     int     33              ;Perform operation (depends on AH)
finerr01        jc      finerr          ;If it failed, exit with NOT OK
                ret

getbit          add     dl,dl           ;Get a tag bit
                jnz     stillbitsleft   ;If zero, that bit was the marker, so
                                        ; we must read a new tag byte from
                xchg    ax,dx           ;\ the infile buffer
                call    getesi          ; >Emulate mov dl,[esi], inc esi
                xchg    ax,dx           ;/
                stc                     ;Carry flag is end marker
                adc     dl,dl           ;Get first bit and set marker
stillbitsleft   ret                     ;Return with bit read in flag C

newtest         cmp     edi,[limit32]   ;Check if we've run out of memory
                jc      endtest         ;NO: end test
                pushad                  ;Keep registers
                mov     dx,freemem
                mov     ecx,32768+65536 ;CX=32K will be written first
                                        ;ECX=96K data will be moved then
                call    writefile       ;Write 32K of data
                sub     edi,ecx         ;Set pointer to origin32=limit32-96K
                mov     esi,[freemem32] ;Output data will be moved 32K back
                xchg    edi,esi         ;Swap source and destination pointers

otherrepmovsb   call    getesi          ;  \
                call    putedi          ;   >Emulates rep movsb
                loop    otherrepmovsb,ecx ;/
                popad                   ;Restore registers
                sub     esi,eax         ;Update read pointer (sub 32K if
                                        ;   we are in the repmovsb loop)
                mov     ah,128          ;EAX=32K
                sub     edi,eax         ;Update write pointer
endtest         ret

putedi          push    edi             ;----->Emulate mov [edi],al in 16 bit
                pop     bx              ;    /  code (as mov [edi],al gives
                pop     bx              ;   /   a nasty fault)
                ror     bx,4            ;  /
                mov     es,bx           ; /
                mov     [es:di],al      ;/
                inc     edi             ;Update write pointer
                xor     eax,eax         ;Clear EAX
                ret
unitoutfile     db      "c:"
notok           db      "NOT "
noerr           db      "OK$",0

testitnow       lodsb                   ;Parse one byte
                cmp     al,32           ;Is it space?
                jc      finerr01        ;Below space: bad arguments > exit
                ret

handlein        EQU     testitnow
handletmp       EQU     testitnow+2
freemem32       EQU     testitnow+4
limit32         EQU     testitnow+8
                                        ;Stack is between program and 2048
inbuff          EQU     2048            ;Place for 32K infile reading buffer
freemem         EQU     inbuff+32768