Category "parity"

Google CTF 2021 Raiders of Corruption Writeup

Am kinda looking for explanation for the CTF's second portion of the code where there is the parity_in_slice variable that is used in the official writeup. From

One instruction to clear PF (Parity Flag) -- get odd number of bits in result register

In x86 assembly, is it possible to clear the Parity Flag in one and only one instruction, working under any initial register configuration? This is equivalent