This is pretty much all x86 chips as far as I'm aware: opcode 0x90 which is equivalent to XCHG AX,AX. The 8080 and Z80's NOP was at opcode 0. Which was neat be

This is pretty much all x86 chips as far as I'm aware: opcode 0x90 which is equivalent to XCHG AX,AX. The 8080 and Z80's NOP was at opcode 0. Which was neat because you could make a "NOP slide" simply by zeroing out memory.