1. xerox 560 computer system - The UK Mirror Service

Status information for an S10 instruction isalways returnedvia condition code bits. Additional information may berequested and returned via the general registers as specifiedby the R field of the S10 instruction. However, thereturn of the additional information is dependent uponconditions encountered within the addressed I/O subsystem(see meanings of condition code settings).If the R field is coded with a 0, no additional status informationis requested.If the R field is coded with an odd value, one word ofstatus information is requested to be loaded into register R.The format of this information is as follows:If the R field is coded with an even (nonzero) value, twowords of status information are requested. The format ofinformation within register Ru1 is as shown above. Theformat of information within register R is as follows:These responses provide the program with information necessaryto determine the current status of the addressed I/osubsystem. The byte count field indicates the number ofbytes that are to be transmitted to or from memory in theoperation called for by the current command doubleword.The other fields are described in Tables 14-17.Affected: (R), (Ru1), CCThe meaning of the condition code bits during an SIO instructionis:2 3 4 Meaningo 0 0 0 I/O address recognized, S10 accepted, andstatus information in general registers iso 0ooocorre~t.o For RMP, I/O address recognized and S10accepted; however, status i nformati on ingeneral registers may be incorrect. ForMIOP, not possible.0 0 I/O address recognized, SIO not acceptedbecause device controller or device is busy,and status information in general registers iscorrect.o For RMP, I/O address recognized, SIO notaccepted because device controller or deviceis busy, and status information in generalregisters may be incorrect. For MIOP, notpossible.o Processor Interface detected parity error onreturned status and/or condition code. Theresult of the SIO is indeterminate.2 3 4 Meaningo 0 I/o address not recognized, SIO not accepted,and status information returned togeneral registers is incorrect.o No I/O address recognized and SIO abortedbecause an error detected when the lOP attemptedto read and transfer the _S10 parameters(device/device controller address, Rfield information, and first command doublewordaddress) from the BP to the lOP via mainmemory. Status information returned to generalregisters is incorrect.If CC4 = 1, the MIOP is in test mode and the meaning ofthe condition code during an SIO is:TID2 3 4 Meaningo 0oSet test mode is successful.Set test mode is successful, but a Bus CheckFault was detected.TEST INPUT/OUTPUT(Word index alignment, privileged)TEST INPUT/OUTPUT is used to make an inquiry on thestatus of data transmission. The operation of the selectedlOP, device controller, and device is not affected, andno operations are initiated or terminated by this instruction.The responses to no provide the program with the informationnecessary to determine the current status of the device,device controller, and lOP, the number of bytes remainingto be transmitted into or from main memory in the operation,and the present point at which the lOP is operating in thecommand list.If the R field of the no instruction is 0, no generalregisters are affected, but the condition code is set.If the R field of no is an odd value, the condition codeis set and the I/o status and byte count are loaded intoregister R as follows:If the R field of the no instruction is an even value andnot 0, the condition code is set, register Ru1 is loaded asshown above, and register R is loaded as follows:Refer to Tables 14 -17 for functions of individual bits withinstatus words.Affected: (R), (Ru1), CC136 Input/Output Instructions