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INS - Output String from Port (80186+)

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.

see also INS


	OUTS	dest,port
	OUTSD			; (386+ only)

Modifies flags:


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 != IOPL
second number is the timing when: CPL > IOPL
third number is the timing when: virtual mode on 486 processor
back2root/ibm-pc-ms-dos/instr/outs.txt · Dernière modification : 2023/02/24 14:16 de frater