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FNOP

The instruction performs no operation. It is used to provide a padding or to ensure the FPU is in a known state.

The following table covers what the source and destinations can be.

DO NOT support LOCK

The instruction is available in both 64-bit and compatibility mode. It does not affect any architectural registers or flags.

The instruction is primarily used for alignment purposes or to provide a target for breakpoints without altering the program state. Since it has no operands, it cannot trigger any floating-point exceptions.