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INS

Reads a word from the specified port and stores it into the accumulator register.

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

DO NOT support LOCK

The instruction is available in 64-bit mode, 32-bit mode, and 16-bit mode. In 64-bit mode, the destination register is always AX (the lower 16 bits of RAX).

The port address MUST be between 0 and 65535. If a register is used to specify the port, only the lower 16 bits of the register are used. In 64-bit mode, the INS instruction is typically used in compatibility mode; however, direct I/O access depends on the I/O privilege level (IOPL) and the I/O permission bitmap in the TSS. Failure to have sufficient privilege SHALL result in a General Protection Exception (#GP).