1. xerox 560 computer system - The UK Mirror Service
1. xerox 560 computer system - The UK Mirror Service
1. xerox 560 computer system - The UK Mirror Service
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o 2 3 4 5 6 78 9 10 11 12 13 '4'5 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31MnemonicSIOTIOTDVHIORIOPOlP111* I Operation Code R X t&o~~ I/o Address I ~~~~~~;:~~:!;;-~. ~--------------~--------~------~-~~-----~~----------------------------~-ing and/orOperation Code(Hexadecimal)444444CDEFFFRRRRRRXxxxxxoo 0)15 (2) 17 18 20 21 23 24 27 28 31o 000 DCACA UA 1 DCA DAo 000 DCACA UA1 DCA DAo 000 DCACA UA1 DCA DAo 000 DCA000 CA UA1 DCA DA001 CA010 CAindexingPOlRAlO46FERRXxo 1 1CA00 000o Portions of a word format that are shaded represent bits that are reserved (after the I/o address is generated) andmust be coded with zeros to ensure program compatibility with possible enhancements to software and/or hardware.o OCE = operation code field extension; CA = cluster address; UA = unit address; DCA = device controller address;DA = device address.o To address a single-unit device controller, bit 24 must be a 0; to address a multiunit device controller, bit 24must be a <strong>1.</strong>Figure 13. Formats of I/O InstructionsTable 13.Description of I/o InstructionsBit Applicable InstructionsPosition (Mnemonics) Function and/or Description0 A!! I/O instructions If this bit is a 1; bits 15-31 of the initla! Vo instruction are modified by indirectaddressing.1-7 SIO, no, TDY, and AIO For these four instructions, the operation code uniquely defines the I/O operationthat is to be performed.HIO, RIO, POLP, and Within bit positions 1-7, these four instructions all have the same operationPOLR code (X I 4F'). <strong>The</strong> instructions are differentiated by using bits 15, 16, and 17as an extension of the operation code field.8-11 SIO, no, TDY, and HIO <strong>The</strong> value of the R field specifies how much status information is requestedfrom the addressed I/O sub<strong>system</strong> (lOP, device controller, and device) andinto which general register{s) the status information is to be loaded. If thevalue of the R field is even and not 0, two words of status infol'rTIution OlE: IE:-quested to be loaded into registers Rand Rul. If the value of the R field is odd,one word of status information is requested to be loaded into register R.RIOAlthough the R field is not used by the RIO instruction, the R field may becoded with any value as required by the program.128 Input/Output Instructions