I'm reading through a disassembled win32 c++ program and I see quite a few:
AND AL,0xFF
Is this completely pointless or why would the compiler generate these?
Here is a longer example:
movsx eax, byte ptr [ebx]
shl eax, 18h
movsx edx, byte ptr [ebx+1]
shl edx, 10h
add eax, edx
movsx ecx, byte ptr [ebx+2]
shl ecx, 8
add eax, ecx
movsx edx, byte ptr [ebx+3]
add eax, edx
xor edx, edx
call sub_43B55C
mov ecx, eax
mov edx, eax
sar ecx, 10h
and al, 0FFh # <----
sar edx, 8
and cl, 0FFh # <----
mov [esi], cl
and dl, 0FFh # <----
mov [esi+1], dl
mov [esi+2], al
add ebx, 4
add esi, 3
inc ebp
cmp ebp, 6
jl short loc_43B5E4
The flags aren't being checked after these operations so that can't be the purpose. After the AND, the values in AL, CL, and DL are being moved to [ESI + n].