This was done for speed. XOR is a very fast operation on some processor types (e.g., 8086). Along similar lines, we were taught to use XOR to zero a register, because XORing it with itself was much faster than assigning a constant value to the register. Whether it's actually any faster in Perl than the equivalent swap, I don't know, but it would be faster in some assembly languages. So, three XORs would accomplish the swap faster than the usual three assignments, too. How many times a second does this need to run? You might want to leave it alone, if it's a flight control system, or at least do a benchmark before you change it.

In reply to Re: Flying Obfu by jonadab
in thread Flying Obfu by awkmonk

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