OUT - Output Data to Port Usage: OUT port,accum Modifies flags: None Transfers byte in AL,word in AX or dword in EAX to the specified hardware port address. If the port number is in the range of 0-255 it can be specified as an immediate. If greater than 255 then the port number must be specified in DX. Since the PC only decodes 10 bits of the port address, values over 1023 can only be decoded by third party vendor equipment and also map to the port range 0-1023. Clocks Size Operands 808x 286 386 486 Bytes immed8,accum 10/14 3 10 16 2 immed8,accum (PM) - - 4/24 11/31/29 2 DX,accum 8/12 3 11 16 1 DX,accum (PM) - - 5/25 10/30/29 1 - 386+ protected mode timings depend on privilege levels. first number is the timing when: CPL ó IOPL second number is the timing when: CPL > IOPL third number is the timing when: virtual mode on 486 processor
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