Loads data from port to the destination ES:(E)DI (even if a destination operand is supplied). (E)DI is adjusted by the size of the operand and increased if the Direction Flag is cleared and decreased if the Direction Flag is set.
For INSB, INSW, INSD no operands are allowed and the size is determined by the mnemonic.
see also OUTS
INS dest,port INSB INSW INSD ; (386+ only)
386+ protected mode timings depend on privilege levels.
first number is the timing if: CPL ó IOPL
second number is the timing if: CPL > IOPL
third number is the timing if: virtual mode on 486 processor