Function at 0x10021580
Capabilities:
Check if file exists
Encode data using xor
Get system information on windows
Read file via mapping

Disassembly:
push ebp
mov ebp, esp
sub esp, 0x60
mov eax, dword [0x1015050c]
xor eax, ebp
mov dword [ebp - 4], eax
mov eax, dword [ebp + 0xc]
push edi
mov edi, dword [ebp + 8]
mov dword [ebp - 0x2c], eax
mov eax, dword [ebp + 0x10]
mov dword [ebp - 0x38], eax
mov eax, dword [edi + 0x20]
cmp dword [eax - 0xc], 0
je 0x100217b6
push eax
call dword [sym.imp.SHLWAPI.dll_PathFileExistsW]
test eax, eax
je 0x100217b6
push ebx
push esi
push 0
push 1
push 3
push 0
push 7
push SysReAllocString
push dword [edi + 0x20]
mov ebx, 0xffffd8f0
call dword [sym.imp.KERNEL32.dll_CreateFileW]
mov esi, eax
mov dword [ebp - 0x3c], esi
test esi, esi
je 0x10021797
cmp esi, 0xffffffff
je 0x10021790
push 0
push 0
push 0
push 2
push 0
push esi
call dword [sym.imp.KERNEL32.dll_CreateFileMappingW]
mov dword [ebp - 0x24], eax
test eax, eax
je 0x10021790
mov esi, dword [edi + 8]
lea eax, [ebp - 0x60]
push eax
call dword [sym.imp.KERNEL32.dll_GetSystemInfo]
mov eax, esi
xor edx, edx
div dword [ebp - 0x44]
mov eax, dword [edi + 8]
push 0
sub esi, edx
push esi
push 0
sub eax, esi
mov esi, dword [ebp - 0x24]
push 4
push esi
mov dword [ebp - 0x1c], eax
call dword [sym.imp.KERNEL32.dll_MapViewOfFile]
mov dword [ebp - 0x30], eax
test eax, eax
je 0x10021786
mov ebx, dword [ebp - 0x1c]
add ebx, eax
mov dword [ebp - 0x20], ebx
je 0x10021778
lea eax, [ebp - 0x14]
push eax
push dword [edi + 0xc]
push ebx
call fcn.10029ed0
add esp, 0xc
lea edx, [edi + 0x10]
lea ecx, [ebp - 0x14]
mov esi, 0xc
mov eax, dword [ecx]
cmp eax, dword [edx]
jne 0x100217ac
add ecx, 4
add edx, 4
sub esi, 4
jae 0x10021670
mov eax, dword [edi + 0xc]
push 0x10155584
push eax
mov dword [ebp - 0x28], eax
call fcn.10073e04
mov esi, eax
add esp, 8
mov dword [ebp - 0x1c], esi
test esi, esi
je 0x10021775
push dword [ebp - 0x28]
push 0
push esi
call fcn.1008e9b0
mov dl, byte [ebx]
add esp, 0xc
movzx eax, dl
mov ecx, eax
mov byte [esi], dl
mov ebx, dword [edi + 0xc]
mov esi, ebx
shl ecx, 8
or ecx, eax
mov byte [ebp - 0x15], dl
shl ecx, 8
or ecx, eax
shl ecx, 8
or ecx, eax
lea eax, [ebx - 4]
mov dword [ebp - 0x34], ecx
mov ecx, 1
cmp eax, ecx
jbe 0x10021711
mov eax, dword [ebp - 0x1c]
mov ebx, dword [ebp - 0x20]
sub ebx, eax
mov dword [ebp - 0x28], ebx
lea edx, [eax + 1]
jmp 0x100216f6
mov ebx, dword [ebp - 0x28]
mov eax, dword [ebx + edx]
lea edx, [edx + 4]
xor eax, dword [ebp - 0x34]
add ecx, 4
mov dword [edx - 4], eax
mov ebx, dword [edi + 0xc]
mov esi, ebx
lea eax, [ebx - 4]
cmp ecx, eax
jb 0x100216f3
cmp ecx, ebx
mov ebx, dword [ebp - 0x1c]
jae 0x1002173f
mov eax, dword [ebp - 0x20]
lea edx, [ecx + ebx]
sub eax, ebx
mov bl, byte [ebp - 0x15]
mov dword [ebp - 0x20], eax
mov al, byte [edx + eax]
lea edx, [edx + 1]
xor al, bl
inc ecx
mov byte [edx - 1], al
mov esi, dword [edi + 0xc]
mov eax, dword [ebp - 0x20]
cmp ecx, esi
jb 0x10021726
mov ebx, dword [ebp - 0x1c]
push dword [ebp - 0x38]
mov eax, esi
push dword [ebp - 0x2c]
cdq
push edx
push eax
push ebx
push dword [edi + 0x20]
call fcn.1007b630
test eax, eax
mov ecx, 1
mov esi, 0xffffd8f0
cmovns esi, ecx
push ebx
mov dword [ebp - 0x2c], esi
call fcn.10073af0
mov ebx, esi
add esp, 4
mov esi, dword [ebp - 0x24]
jmp 0x1002177d
mov esi, dword [ebp - 0x24]
mov ebx, 0xffffd8f0
push dword [ebp - 0x30]
call dword [sym.imp.KERNEL32.dll_UnmapViewOfFile]
push esi
call dword [sym.imp.KERNEL32.dll_CloseHandle]
mov esi, dword [ebp - 0x3c]
push esi
call dword [sym.imp.KERNEL32.dll_CloseHandle]
pop esi
mov eax, ebx
pop ebx
pop edi
mov ecx, dword [ebp - 4]
xor ecx, ebp
call fcn.10073638
mov esp, ebp
pop ebp
ret 0xc
mov esi, dword [ebp - 0x24]
mov ebx, 0xffffd8ee
jmp 0x1002177d
mov ecx, dword [ebp - 4]
mov eax, 0xffffd8ee
xor ecx, ebp
pop edi
call fcn.10073638
mov esp, ebp
pop ebp
ret 0xc