Comment on Windows Defender Anti-vitus Bypassed Using Direct Syscalls & XOR Encryption
Malfeasant@lemm.ee 4 weeks agoan x86 assembly programmer
Ftft. not all CPUs have an xor register with itself instruction.
Comment on Windows Defender Anti-vitus Bypassed Using Direct Syscalls & XOR Encryption
Malfeasant@lemm.ee 4 weeks agoan x86 assembly programmer
Ftft. not all CPUs have an xor register with itself instruction.
QBertReynolds@sh.itjust.works 4 weeks ago
There are a lot more architectures than just x86 that are capable of XORing a register with itself (ie. ARM and RISC-V), and if you took OP to mean the accumulation register specifically, pretty much all CPUs going back as far as I can think have had that functionality.
Malfeasant@lemm.ee 4 weeks ago
Yes, but it’s not universal that xoring a register with itself is more performant than simply loading it with 0.
QBertReynolds@sh.itjust.works 4 weeks ago
I never made that claim, nor did the person you corrected.
Malfeasant@lemm.ee 4 weeks ago
Yes, but that’s why x86 assembly programmers do it…