OUTS - Output String to Port (80188+) Usage: OUTS port,src OUTSB OUTSW OUTSD (386+) Modifies flags: None Transfers a byte, word or doubleword from src to the hardware port specified in DX. For instructions with no operands the src is located at DS:SI and SI is incremented or decremented by the size of the operand or the size dictated by the instruction format. When the Direction Flag is set SI is decremented, when clear, SI is incremented. 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 port,src - 5 14 17 1 port,src (PM) - - 8/28 10/32/30 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
Back to Intel Instruction Set page.