///MBusSpecs.tiogaWrittenby:Sindhu,September1,19841:51:14pmPDTLastEditedby:Sindhu,September10,19846:47:15pmPDTLastEditedby:Barth,December13,19842:08:47pmPSTTheDragonMBusDescriptionandSpecificationsReleaseas[Indigo]Documentation>MBus>MBusSpecs.tioga,.presscCopyright1984XeroxCorporation.Allrightsreserved.Abstract:ThismemodescribestheDragonMbus.ItisintendedtobeusedbothasaconvenientsourceforinformationabouttheMbusandasareferencemanualforbusspecifications.ThememobeginswithabriefoverviewoftheMbus.Itthenlistsallthebussignalsanddefinesthemeaningofeachsignalgroup.Next,itusesthesesignalstodescribeindetailhowthebusoperatesatboththecycleandtransactionlevels,andhowcertaintransactionsareusedtomaintaincacheconsistency.Finally,itgivesthedetailedtimingofthebustransactionscurrentlydefined.XEROXXeroxCorporationPaloAltoResearchCenter3333CoyoteHillRoadPaloAlto,California94304ForInternalXeroxUseOnlypО_:НБО]⌠НБНХН<Н@Н!щН#jН&╟Н+≤Н-ЦО[КНБНЧНEН≤Н°Н$9Н&vН)╪Н.╔Н0ПОZDНБНЧНEН≤НиН#Н%TН( Н-┐Н/нqОQЪНБН НБН" rОM НБ НDНІ sОHНБНeОHН╒tНОHОHНgП1Н─О>'НБН"НВН Н┬Н!JН#k Н+Н/Н1zН3Н5ЁН8zН:NН;rО<─НБНН`Н8О91НБНъНRННFН■Н"ЪН)+Н*СН-─Н/2Н2ЫН4SН7╡Н:╧Н<╦Н?FО7┼НБН ННqН#Н%RН'=Н+Н/└Н5 Н9Н:xН>О5ЦНБН(Н3Н│НwН"ЎН&6Н)Н,&Н2┼Н4┼Н88Н; Н?0О4;НБ Н╣НWНcН!╠Н&бН/EН1ВН5ЁН7∙Н=╞О2■НБНёННґН#чН&цН,ЇН1│Н3═Н6├Н9╧О0МНБНwОэНБtОэН.╪Н2Ъ О5Н.╪Н2Н5&Н;гО▌Н.╪Н2YН7cН9МОФН.╪Н2Н5┼ Н<6rО IНБНЫН▒Н"=Н&оЪ┌TVm$∙DRAGONMBUSSPECIFICATIONS2Contents1.Introduction2.BusSignals3.BusOperation4.BusTimingA.IOAddressSpaceDefinitionDRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН yН!$ОgОgН!ЬxН%ХОgОgН'бyН(╙ОgОgН)▐xН+ОgyОgН+иtОgНEиzО^УНБ{О[їНєН0ОXXНєН0НРОU НєН0НРОQ╩НєН0НРОNlНєНsН°Н╪Нх yОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡Ъ⌠TVm$qDRAGONMBUSSPECIFICATIONS31.IntroductionTheMbusisahighbandwidthsynchronousbusthatconnectsthecomponentsofaDragoncluster.ADragoncluster(Figure1)consistsofoneormoreDragonprocessorsattatchedtothebusthroughcaches,somemainmemory,amapprocessor,adisplaycontroller,andoneormoreI/Oprocessors.Thereareapproximately75wiresontheMbus.Themultiplexeddata/addresspath,whichischeckedbyasingleparitybit,is32bitswide.Fouradditionalwiresdefinethebuscommand,whichencodestheactionduringthecurrentbuscycle(abuscycleisdefinedinthesamewayasaprocessorcycle:namely,onecompleteperiodofthesystem-widetwo-phaseclock;thesetwophasesarelabeledAandB,byconvention).Apairofrequest/grantlinesforeachbusrequestoralongwithmiscellaneouscontrollinesmakeuptheremainingsignalsonthebus.AddressesontheMbusarerealasopposedtovirtual,andtheunitofaddressingisthe32bitword.However,forefficientbusutilizationthetransfertoandfrommemoryisin4-wordchunkscalledquads.Thereisasingle,centralarbiterthatpermitstheMbustobetimemultiplexedbetweentwoormorecontendingdevices.Thesedevicesmakerequeststothearbiterusingthededicatedrequestlines,andthearbitergrantsthebususingthededicatedgrantlines.Thearbiterusesaround-robinalgorithmtoguaranteefair(bounded-time)servicetoeachrequestor.Adevicethathasbeengrantedthebusiscalledbusmaster.Thesequenceofcyclesinitiatedbyamasterwilltypicallyinvolveatleastoneotherdeviceonthebus;suchadeviceiscalledaslave.Currently,theonlydevicesthatcanbecomemasterarethecaches.Cachescanalsoactasslaves,ascanalloftheotherdevices.SomeMbuscommandsstartafixedsequenceofcyclesthatarereferredtoastransactions.Transactionsprovidethemechanismforusingthe32-bitwidedatapathfortransferringmulti-worditemssuchasquads,andalsopermitthetransferofdataonthebustobeflowcontrolled.Fivetransactionsarecurrentlydefined:ReadQuad,WriteQuad,WriteSingle,IORead,andIOWrite.ReadQuadpermitsacachetoreadaquadfromanothercacheorfrommainmemory.WriteQuadisthelogicalinverseofReadQuad.WriteSingleistheoperationusedbyacachetowriteasinglewordtoanothercache.IOReadandIOWritearegeneralizedIOoperationsthatareusedtodomapoperationsaswellastotransferdatatoandfromIOdevices.Theremainderofthedocumentgoesintogreaterdetailaboutthestructure,operation,andtimingoftheMbus.Thenextsectionliststhebussignalsindetailandgivesthemeaningofeachsignal.Section3nextusesthesesignaldefinitionstoexplainhowthebusoperates:itdiscussesarbitration,liststhesetofbuscommandscurrentlydefined,showshowthesecommandsareusedineachofthepossibletransactions,andhowtransactionsareusedtomaintaincacheconsistency.Finally,Section4discussesthetimingofarbitrationandofeachtransactionindetail.Theappendicesprovidedetailsthatdonoteasilyfitintothemaindocument.2.BusSignalsTheMbushas73signallinesthatarelistedbelow,togetherwiththemeaningofeachgroupoflines.Thedescriptionusesthefollowingnamingconventions:S[a..b)denotesagroupofb-alinesthatencodethebitsrepresentingthesignalS;DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН yН!$ОgОgН!ЬxН%ХОgОgН'бyН(╙ОgОgН)▐xН+ОgyОgН+иtОgНEиzО^УНБНЎxО[іНєНtНFНуН8НZНxН%L Н-2Н/аН2┤Н8Н:r ОYЪНБН╘НАНННLНГН"УН'iН,`Н.Н3*Н4ЯН7╚Н9}Н=ОXXНБ Н^Н+НЎНН!|Н&≤Н+$Н.⌡Н1ЩН7іН8ЄН;╡ ОV╟НБННЎ НVН Н ╧Н"}Н&Н(щ ОT5НєН²НХН БН"ЎН&IН(GН*·Н,pН/яН2║ pН:/ОT5ОT5Н:ъxН<╟ОT5pОT5Н=axОR▌НБНWН[НҐННСН Н#ТН'АН*MН+ўН-┼Н0!Н4╣Н8 Н>▀ОPГНБН'Н▓pН4ОPГОPГНоxНйОPГОPГН╡Н"лН(Н*zН.·Н3Н5┘Н:ZН<ЭН@{ОO?НБН≥Н-Н╨НшН╙Н +Н#иН&бН(▒Н)шН0Н4Н9iН<6ОM≤НБНKНН НOН%ЮН)ШН-⌠Н0MН4аН7#Н;ЗН=■Н@ZОKЯНБННдН{Н~pН bОKЯОKЯН ФxН$}ОKЯpОKЯН%.xОKЯН(ПН,VН.ЎН2Н4зН;Н?ОJIНБpН┬ОJIОJIН#xОJIНН=Н"ДН$ХН':Н-ґН2Н4Н6XН9╞Н@ОH╒НБНYНKНЫНeН3НЫН"┼Н$PН)Н+ЙН.aН1]Н3- Н: Н;█Н>Н@ОFШНБНPН┴НкН!(Н#ц Н*?Н,ёН1ЁН3fН6"Н9█Н>ЪН@pОESНБН■НHpН?ОESОESНОxН▒ОESОESОBьНєН═НН,НjН ЛН%XН(!Н-Н/kН1AН3рН5{Н7gН:┤ ОA1НБН;НяН─НЩ Н#Н(~Н,jН1pН4╪ОA1ОA1Н5@xОA1Н9кН;cН=ґО?┼НБН├НАННАН#oН&!Н({pН,ФО?┼О?┼Н-≈xО?┼Н0ЩН3XН5ИН9█Н;ХО=БНБН'Н║Н*Н!LН$ВН&р Н/FН67Н8≈Н?⌠О<;НБ НдНWНН"Q Н)[Н*ТН/FН2!Н4єН8 Н=Н?┤О:■НБНzН·pНaО:■О:■НwxО:■НТНЫН&Н'СН,Н1їН3оН5%Н9бН<≥О8ЛНБН▓ННН■НН"2Н$Н&SН)@Н,OН-VН1xН2аН6√pН7²О8ЛО8ЛН8"xН:kО8ЛО8ЛН;├ О7EНБНiН╙Н Н░НBН$─Н)Н+⌠Н.Н3■Н8oН;!Н>Н@pО5·НБН%НтН_НOННgН!О3"НєН~Н\НВН АН#ЖН%$Н(іН.⌠Н0PН4LН7Н9wН>ҐН@ppО1{НБxНшО1{О1{Н▄Н╛Н$ъН'gН.аН1'Н4ЬН7─Н;÷Н?О/тНБННqНП Н#-Н&МН*4Н+ВН0hН35Н6Н:·Н=О.,НБН╞НхНЦНWННдНиН!В Н)~Н,ЇН4KН6ЁН<єО,┘НБН< НьН%вН+┌Н.UН4АН;ЦН@ТО*чНБН╛НXНpН≈ННxН$│Н(JН*Н-qН0КН70Н>UН?ЎО)6НБН9НИН÷Н!\ Н(ДН*MН,╙Н2яН6Н8Н9+Н<ТН>═О'▐НБННЦНaННН" Н'фН*tН/БН2+ Н9^Н;p О%ХНБН≈НяНСН┬НvНw Н$Н%═Н(tН* Н+²Н0▐Н3zН5Н7ґН:ШН<ЩО#mНєНіНiНLНжН&nН)╡Н,╣Н1|Н5rН9Н< О!еНБ НfНН{Н6Н ≈Н"sН%ИН(цН+уН0tН37Н5≥Н81Н<ёН>SО НБН╛Н1НёНPНН"_Н'LН,?Н-├Н0╗Н3╣Н7QН;O ОwНБНoН!ННBНЇН"}Н#╡Н)WН0RН2СН51Н7,Н8цН;9ОоНБНЗН▄НтН"Н%жН,ЖН/└Н2ЗН4ЦН8OН:BН<эО(НБНаНН┼Н$Н&kН)ўН+cН1%Н4ЬН=О│НБНхННяН8Н!≥Н#X Н*$Н,БН.╒Н1з Н8эН:▒Н?FОыНБ НТНЪНOН"Н$$Н&≥Н*cН,2Н/ Н1jН4ГzО<НБНЎН xО МНєН|НWНННdНJН!5Н$qН'@Н)■Н-?Н1єН7 Н:$Н<└ОFНБНиН(НXН?Н╡Н!╦ Н(ЬН,Н.╛Н4МН:О ·НБО ·Н7НTН░НєНoН!ЙН%7Н(Н,эН/NН2Н9КН<\Н@YyОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡ETVm$tDRAGONMBUSSPECIFICATIONS4mostsignificantbitsofthesignalarewrittenleftmost.Asignalrepresentedbyasinglewireiswrittenunencumberedwiththe[)notation.Allsignalsareassumedtofollowpositivelogicunlesstheyhavean"n"atthebeginningofthesignalname.Finally,theletters"AB"areappendedtosignalSifitiscomputedduringphaseAandbecomesvalidduringthefollowingphaseB.SlavesshouldnotassumethatthebusbecomesvalidduringA.TheactualsetuptimeatwhichthebusbecomesvalidattheslavespriortothefallingedgeofBhasnotyetbeendetermined.Itisapproximately20ns.MCmdAB[0..4)ThesefourlinesencodetheMbuscommand.TheMbuscommandspecifiestheactioninprogressduringthecurrentbuscycle;itmaybeassertedeitherbythemasterorbyaslave.ThecommandscurrentlydefinedarediscussedlaterinSection3.2.MDataAB[0..32)Theinterpretationofthese32linesdependsonMCmdAB[0..4).FormostcommandstheMDataABlinessimplyrepresentthe32-bitaddressordatacorrespondingtoareadorwrite;forothercommandstheinterpretationismorecomplicated.ThedetailedinterpretationappearsinSection3.2.AswithMCmdAB,theselinesalsomaybeassertedeitherbymasterorslave.MParityABThislinecarriestheparitybitforMDataAB[0..32).Theparitycomputedisoddandisvalidonlyduringdatatransportcycles.nMSharedThislineisusedbythecachestomaintainconsistencyformultiplecopiesofread/writedata.Whenacacheputsoutareadorwriterequestonthebus,othercachesmatchtheaddressonthebuswithaddressesforwhichtheyhavevaluesstored.WheneveracachefindsamatchitpullsnMSharedlow,signalingthatthedatumisshared.Notethatthissignalisassertedwhenlow.nMAbortThislineisusedtopreventmemoryfromrespondingtoaReadQuadandhaveacacherespondinstead.LogicallyspeakingnMAbortisnotnecessary,sincenMSharedcanalsobeusedtogetthememorytoabort.However,thiswouldrequiretheimplementationtokeepanadditionalstatebitforeachcacheentry,whichisexpensive.ItwouldalsorequiremorebandwidthfromtheRAMinthecache.Notethatthissignalalsoisassertedwhenlow.nMErrorThislineisusedtosignalabuserror.Theonlybuserrorcurrentlydefinedisbusparityerror.Notethatthissignalisassertedwhenlow.Normally,apullupresistorensuresitisnotasserted.DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН yН!$ОgОgН!ЬxН%ХОgОgН'бyН(╙ОgОgН)▐xН+ОgyОgН+иtОgНEиxО_,НБН\ ННпНїН $Н$,Н&²pН+nО_,О_,Н+яxН0О_,О_,Н1║Н3JН7S Н>шН@ТО]┘НБНЮНН─НEН%ЎН(ЛН+^Н,яН3AН5іН:(Н<▌О[щНБН┘НЁНҐНН!Н$ Н'\Н)AН+БН-oН/дН6$Н7рН:'Н>ОZ6НБНЙНHН_Н2Н └Н&ыН(├Н,pН-╧Н/Н0mН1вН8CН<╡Н@▒ОX▐НБН╟НaНъНfН!щН(Н+ЧН/ Н3RН7ЕН:pН?PОVГНБНKНЙН▌НЧН!xН#СН&тН*ЮН.■Н1бН3dН7{Н9ДН<┐ОU@НБНLНГНHН6Н╚Н\Н!ҐН&Н)LН+Н,vН.МН1dН3╟Н7 Н?8Н@╡ОS≥НБНД{ОPIНБxОLЫНєН╛НЇНЬН ╡Н#Н$ЫН'√Н.ЮН1©Н3═Н6=Н<╔ОKRНБН=НRНЭНeН рН#-Н'РН*┘Н.mН/©Н2©Н4╚Н9ъН=гН?ЎОI╚НБН?НПНыНОННяН%ёН+mН0ZН2⌡Н8▒Н;ёН=>ОHНБ{ОDЄНБ xОAdНєН╧ Н√Н▄Н#SН%uН(НН. Н0чН;ыН>аО?ҐНБНXНGН zН$EН)EН/сН2цН7KН<еН?О>НБННжН'НiН TН$rН&вН*²Н1╙Н41 Н<ЬН>▀ОН6▒НО(▓НБНdН╧НJНfН!·Н$/Н&ВН*CН0┬Н2ВН76Н:xН=ПО&ЙНБНУН≈НйН═Н#Н$QН(Н)ъН-EН4Н7Н<ФН?ЎО%CНБН2Н·НъНVН $Н"фН&╠Н(Н-TН1 {О!СНБxОєНєНЇНgНкНН╗Н"║Н(Н+h Н2}Н4%Н5HН<'Н>вОЭНБНhН░Н/Н vН&цН,пН3JН5Н7Ц Н>╚ОUНБНчН═НёНкН!>Н##Н%ёН(9Н-щН/цН4╚Н;Н=ПОўНБНщНo Н Н"`Н%ЦН( Н.╞Н2Н4aН6яН:4Н>2ОНБНН┤ НыНgН!╚Н$█Н)lН-Н4Н7└Н9ЫН=ЗН?ЎО_НБН┼ННнНpН [Н#(Н$⌠Н)кН-─{ОНБxОюНєН©НwНДН"НяН!ЎН"ИН%│Н)рН,╚Н/гН2_Н5рН;╟Н@╡ОНБН∙Н╗Н.НаН ╚Н#iН'pН(ЬН.KН2Н5яН∙ОKRНБНbНєНўН╔НBН ЖН&kН( Н*├Н0Н4*Н7 Н<┴Н?йОI╚НБНїН÷НШН>Н!NН"ЬН&ЖН)hН-rН3┌Н4ЙН:цН=V{ОF\НБxОCНєНЙНлНdНЩН'"Н)оН+fН0[Н26Н7оН:▓ ОAeНБНН└НСНPН!7Н#╞Н(▓Н-Н.÷Н3>Н5 Н;∙Н>Н@ҐО?ЎНБНmНцНd НWН ЯН#∙Н' Н.Н0─Н5KН9ҐННБНQНiН■Н╪Н+Н вН"эН(TН/рН4эН:НН,Н Н#лН(╨Н+ЫН0,Н1їН7FН9©Н=шО!ЫНБН╦ Н╪НFН Н"0Н'7Н(Н-rН/?Н1ҐН7GН:ЦН?┤О QНБННoН∙НУНҐН$▄Н&A Н-Н2╒Н4≥ Н;▒ ОжНєН█ Н╟НнН"ЇН&FН(jН0,Н1╣Н4ЛН:ЕН=VО.НБНеНeНSННН ╧Н#!Н%GН' Н.▓Н3°Н7OН:АО┤НБН░НHН═НpН$9Н'@Н+⌠Н1QН3Ё Н:ИН<єОЮНБННйН1 НЖН#вН&╟Н+ХН0CН1Щ Н8бН;zН=3Н@eО8НБНAНбН-Н╒Н bН"uН%▐Н(Н)|Н+ЯН-÷Н2~{ОИНБН xО НєН╒Н7НВН к Н'╣Н*/Н,ЄН4ЁН85Н=▓Н?gОСНБННФНвН }Н#jН&Н*ЧН-КН/KН3lН6XН<ЧН@oО KНБН@Ня НвН ^Н$²Н)ПН,JН.шН0яН6qН8FН=Н@°ОєНБНzН+Н╙НAНiН╘Н%%Н'иН*Н,≤Н-ПН1Н3NН7╚Н=tН>┼yОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡Ъ QTVm$,DRAGONMBUSSPECIFICATIONS6cycleinwhichitissuesthebusbyassertingtheMGntlineforthehighestprioritydevicethathasMRqasserted.Priorityisround-robin,withthedevicelastgrantedthebusreceivinglowestpriority.ThebusrecipientkeepsMRqassertedforaslongasitwantsthebus,andthearbiterinturnkeepsMGntasserted.Ifthemasterisexecutingalongsequenceofcyclesthatisnotrequiredtobeatomicwithrespecttootherdevices,itassertsMNewRqtoindicateitswillingnesstogiveupthebusifthereareotherrequestspending(forcorrectoperation,MNewRqmustbeassertedonlybythecurrentmaster).MNewRqcausesthearbitertodoagrantcycleeventhoughthemasterstillhasMRqasserted.Sincethemasterbecamethelowestprioritydeviceuponreceivingthebus,itwilllosethebusifanyrequestsarepending.Thisstrategypreventsamasterfromhoggingthebus.Atthesametime,itavoidswastingcyclesinthecasethatnodevicesarewaitingtogetthebus.Asolutioninwhichthemasterreleasesandreacquiresthebus,forexample,doeswastecyclesinthiscase.3.2MBusCommandsThereareamaximumofsixteenMbuscommands.Nineofthesearecurrentlydefined,andtherestarereservedforfutureuse.Inthedescriptionbelow,thedecimalnumberinbracketsafterthecommandnameindicatestheencodingforthecommand.DataTransport{0}Thiscommandisusedduringcyclesinwhichdataisbeingtransportedbetweentwocachesorbetweenacacheandmainmemory.MDataAB[0..32)carriesthedata.TheMParitybussignalisvalidonlyduringDataTransportcycles.ReadQuad{1}ThiscommandisissuedbythemasterduringthefirstcycleofaReadQuadtransaction,whichreadsaquadfrommemoryorfromanothercache.Aquadisfourcontiguous32-bitwordsalignedinrealaddressspacesuchthattheaddressofthefirstwordis0MOD4.DuringthiscommandMDataAB[0..32)istheaddressofoneofthewordsinthequad,anditisthiswordthatwillbereturnedfirstduringsubsequentDataTransportcycles.WriteQuad{2}ThiscommandisissuedbythemasterduringthefirstcycleofaWriteQuadtransaction,whichwritesaquadtomemoryortoanothercache.MDataAB[0..32)holdstheaddressofthequadwhich,unliketheaddressforaReadQuadtransaction,mustbe0MOD4.WriteSingle{3}ThiscommandisusedbythemasterduringthefirstcycleofaWriteSingletransaction,whichwritesasinglewordintotherealaddressspace.WriteSingleneverwritesthewordtomemory,butonlytocachesthathavethequadcontainingthewordbeingwritten.MDataAB[0..32)carriestheaddressoftheword.DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН yН!$ОgОgН!ЬxН%ХОgОgН'бyН(╙ОgОgН)▐xН+ОgyОgН+иtОgНEиxО_/НБН`НН1Н▓Н}НГН"┴Н$▐Н*?Н,╘Н0МН3ўН5ЖН8`Н=)О]┬НБН*НЩНvН#Н">Н'AН(╠Н0оН3НН6QН: Н=О[ЮНБНAНьНЄНМОYdНєН│ННтН ╞Н$_Н)°Н+ъН-▓Н0╡Н2eН3аН7╗Н: Н=Н?ЎОWҐНБНUНННФН #Н&;Н'юН*"Н.∙Н0Н61Н7]Н:zН@eОVНБННН╪НiН 2Н"Н$AН(УН,HН1)Н3Н6ГН<@Н=оОTnНБНiН.НrНd Н%uН':Н*?Н,hН.ъН1▄Н3Н6єН9Н<еОRгНБН}НvНJ Н#Н)аН-kН/·Н5Н8tН:╡Н=TОQ НБНвН_Н╟Н"(Н&╟Н(vН*∙Н+жН/┌Н3 Н6kН;6Н=ўОOxНБН═Н3НЗНHН"Н$≈Н)%Н.CН0©Н5Н:(Н>┼ОMяНБНДНjН~НШНлН!©Н$DН'Н(┬Н+OН0нН3GН9хН=ОL*НБНcН┴НУНXН"√Н$РН(]Н*TН,╟Н0)Н3ёН4ЖН96Н>'ОJ┌НБН╨НCН\НTН└Н wН"ТН'РН)йН,=Н.фН2▄Н4CН9╞Н;┤Н?ЎОHшНБНRН\Н Н!║Н$Н&ОН)-pН.ЧОHшОHшН/ўxОHшН2Н5бН9╧Н;gН> {ОE▀НБНННфxОB;НєН■НжННН^Н!Н%░Н'XН)щН1{Н4ЮН6┤Н9ЪНМНБНЫННюН Н#LН%╒Н+ЗН/╟Н5WН7ґН=▀Н?ЎО=EНБpО9УНБНЪxО6╔НєНўНЪНZН├Н#ГН'нН)lН-jН0_Н1╩Н5v Н<╞О4ЧНБН─НаНwНвНРН!╟Н$YН'хН-Т Н8%НаО3WНБН╨НН╗Н■НЪpН"gО3WО3WН#xО3WН%cН)сН3pО0НБН▒xО,ЇНєНЮНdНРН!8Н#VН%ьН*kН.ЧН1─Н4{Н8Н9ЛН;8О+НБНPНxН0НtН#Н&█Н,Н-РН1sН6≤Н;sН=Н@╡О)hНБНН НГНГН ЭН%вН'█Н*LН/>Н2ШН65Н9Н;sН@eО'аНБНAНН║НyНAО'аО'аНRxО'аН≤Н╗Н$pН'Н-r Н7╠Н9Н;{Н@eО&НБН√НXНюНжН█НУН!уН$∙Н%ТН'hН*Н-єН0{Н3/Н5(Н:лН=ґО$rНБ НН:pО!"НБНКxОрНєНшНZНЦН!$Н#=Н%╨Н*GН.жН1RН4HН7ыН9╞Н:ЖО+НБНEНaНrН╙Н#7Н$ТН*pН,CН.Н3Н7ъ О└НБН┘НсН╛НTН╒Н!Н%cН)▀Н+ыН0╠Н2щН3УН:йОэНБНJН;yНoОэОэН│xОэНгpО▄НБ НfxО<НєНЕНnНН eН"┬Н%Н)їН.@Н0гН3гН7aН9BН:⌠ О∙НБНgН╔НвН 2Н$NН(Н+Н-÷Н0┤Н5║Н:⌠ ОННБН╘НїНН┬Н3Н#УН&rН)┬Н+3Н/─Н2KН5▌Н7ЙН;e О FНБНAНйН∙Н$ Н(cН,ҐН/Н4Н5©Н8yОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡еTVm$<DRAGONMBUSSPECIFICATIONS7ChangeFlags{4}ChangeFlagsisusedbytheMapprocessortogetaspecifiedsetofcachestomanipulatetheirmapentries.ThiscommandistypicallyissuedinsideanIOReadorIOWritetransaction.ThesetofcachesaddressedisencodedinMDataAB[0..4].ThevalueallonesindicatesallcachesontheMbus,andanyothervalueindicatesjustthecachesconnectedtotheprocessorwiththisvalueasitsnumber.MDataAB[5..7]isafunctioncodethatspecifiesthemanipulation,andMDataAB[8..31]containsarealpagenumber,whichisvalidonlyforsomeofthefunctioncodes.Theinterpretationofthefunctioncodesisasfollows(inthetablebelowrpstandsforrealpagenumber;vpstandsforvirtualpagenumber;wtEnabledisabitpercacheentrythatmeanswritesarepermittedtotheentry):MDataAB[5..7]MdataAB[8..31]Meaning0rpclearvpValidandwtEnabledforallvp'sthatpointtothisrp1rpsetwtEnabledforthisrp(TheundirectedversionofthiscommandisunsafebecauseitcouldcausewtEnabledtogetsetevenwhenwritesarenotpermitted:eg.twospaces,onewithwritespermitted,theothernot)2undefinedclearvpValidandwtEnabledforallvp's3undefinedclearwtEnabledforallvp'sIORead{5}IOReadisusedbyamasterduringthefirstcycleofanIOReadtransaction.MDataAB[0..31]containstheIOaddress.TheIOaddressspaceiscarvedupintodisjoint,contiguouspieces,withatmostonedevicerespondingtoeachpiece.SeeAppendixAforafulldefinition.IOWrite{6}IOWriteisusedbyamasterduringthefirstcycleofanIOWritetransaction.MDataAB[0..31]containstheIOaddress.IODone{7}IODoneisusedbyaslavedevicetoterminateanIOReadorIOWritetransactioninwhichitisparticipating.MDataAB[0..31]containstheresponseiftheinitiatingcommandwasIORead;MData[28:31]containstheM-Busfaultbits,whichareencodedasspecifiedinDragon.mesa.Reserved{8..14}DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН yН!$ОgОgН!ЬxН%ХОgОgН'бyН(╙ОgОgН)▐xН+ОgyОgН+иtОgНEиpО_,НБ НxО[эНє НЙНlН©Н яН#GН&єН,нН.⌠Н0СН23Н8Н:9Н< Н@oОZ5НБ ННnН≈Н"Н%)Н+≤Н-Н2іН6ьН:ХН<ГОX█НБН╞Н1НН ЩН##Н$ЕН)>Н/·Н1Н6√Н8N ОVФНБНҐНiН\Н▐Н BН"5Н&┬Н(▒Н*СН,пН/аН2{Н5Н8юНІОN║НБНвН▌Н╔НйНiН ≈Н&%Н( Н,Н.EН2┤Н5╣Н;CОLЗНБНNНwН∙Н НжНiН 8Н${Н(}Н*яН1Н2кН5+ОHжНБН} ОHжН-ДОFZН─ОFZН#▌ОFZН-ЦН15Н6aН9ОD╡ОD╡Н-ДН0!Н2Н4ИН7ЇН;VН=Н?іОB6Н─ОB6Н#▌ОB6Н-ЦН0Н6шН9Н;╨Н=┴О@▌О@▌Н-Д Н4©Н9┤Н;@О>ГО>ГН-ДН4EН5╟Н:О=?О=?Н-ДН/:Н3Н6╩Н=∙О;≈О;≈Н-ДН0,Н2IН5▐Н9DН=FН? О9ОО9ОН-Д Н4ЪН7┤Н:┼Н?rО8HНБО6═О6═Н-ДН1Е Н8┴Н:ИН>┬О4$Н─О4$Н#▌О4$Н-ДН15Н6aН9О2|О2|Н-ДН0!Н2О0Н─О0Н#▌О0Н-ДН15Н8Н:MН<=pО,╟НБНxО)`НєНЭН┼НГННPН#ЦН(uН*ЖН-ПН1┘Н3`Н5rН:йО'╧НБ Н!Н⌡Н!Н#BН)4Н,"Н.TН3TН7 Н8╒Н=Н?FО&НБН/ Н,Н╗Н"оН$sН'шН*▓Н.Б Н6 Н7дН;Н?┬О$jНБНCНпН Н7На pО!НБНhxОкНєН4НЇННН`Н#ХН(pН*ГН-вН1bН32Н5:Н:йО#НБ ННnН нН"ЙpОсНБН2xО┐НєНГН3НPН,Н6Н!~Н%ёН'2Н-<Н/ Н4$Н5иН;" ОэНБН═Н©Н%Н╒ Н ≥ Н*рН0FН2ІН8kН9эННБН┬yОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡▀TVm$#DRAGONMBUSSPECIFICATIONS8Commandcodes8through14arereservedforfutureuse.NoOp{15}Thiscommandisusedtoindicateidlebuscycles.3.3MBusTransactionsTherearecurrentlyfiveMbustransactions:ReadQuad,WriteQuad,WriteSingle,IORead,andIOWrite.ReadQuadReadQuadreadsaquadfrommainmemoryorfromacache,dependingonwherethecurrentvaluelies.Recallthataquadisfourcontiguous32-bitwordsalignedinrealaddressspacesuchthattheaddressofthefirstwordis0MOD4.ThenumberofcyclesinaReadQuadisvariablesincethetransactionisflowcontrolledtoallowthememorymoretimetorespondwhennecessary.InthefirstcyclethemastercacheissuesaReadQuadcommand,withMDataABequaltotheaddress.Thenfollowoneormorewaitcycles,andfinallyfourDataTransportcycles,eachcontainingoneofthefourwordsofthequad.Duringthesecycles,MCmdABandMDataABareassertedbytheslave.Notethatthefirstworddeliveredisnotnecessarilythefirstwordinthequad,butthewordactuallyrequestedbytheaddressinthefirstcycle;theotherthreewordsaredeliveredinorderofincreasingaddress(MOD4).WriteQuadWriteQuadwritesaquadtomainmemoryortoawillingcache.ThetransactionstartsoutwithaWriteQuadcommandfromthemaster,withMDataABequaltotheaddressofthequad(notethatthisaddressmustbe0MOD4,unliketheaddressforaReadQuad).ThenfollowzeroormoreNoOpcycles,withMCmdABbeingassertedbythememoryandMDataABdriventothefirstdatawordbythemaster.Whenthememoryisreadytoacceptdata,itsetsMCmdABtoDataTransport.ThisstartsasequenceoffourDataTransportcyclesinwhichthewordsaretransported.WriteSingleWriteSinglewritesasinglewordouttotherealaddressspace.UnlikeWriteQuad,aWriteSingleneversendsthewordouttomemorybutisdirectedexclusivelytocaches.WriteSinglesarenotflowcontrolled,andalwaystaketwocycles.InthefirstcyclethemasterputsoutMCmdAB_WriteSingle;MDataAB_address.InthesecondcycleitputsoutMCmdAB_DataTransport;MDataAB_datatobewritten.IOReadTheIOReadandIOWritetransactionsareusedbycachesasageneralwayofcommunicatingwiththeMapprocessorandwithIOdevices.The32bitaddressofanIOReadorIOWritedefinesalarge,unmappedIOaddressspacethatiscommontoallprocessors.Thisspaceiscarvedupintodisjoint,contiguouspieces,withatDRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН yН!$ОgОgН!ЬxН%ХОgОgН'бyН(╙ОgОgН)▐xН+ОgyОgН+иtОgНEиxО_/НєНgН3НgН"÷Н$└Н&ьН,QН.▌Н2╡pО[ЮНБННxОX░НєНЎНН┼НфН!uН&║Н)XН+О{ОUAНБНННфxОQРНєН{Н╔НXНЕН!∙Н$Н+яН2Е Н:;ОPKНБНqН(pОLШНБxОI╛НєНўНrНюН!cН$ОН(▒Н.#Н0Н3≈Н4ЕН9.Н@ОHНБНН═Н█НYН!ПН&LН)>Н*┼Н.,Н/╩Н2Б Н9ВН>ОF]НБН╣НcННН ╧Н#КН&╧Н)Н.Н/╪Н2Н4СН8|Н9ГyН;ОF]ОF]Н<.xОF]Н>tОCБНєН▒НрН═НґН!pН"╞Н)╙Н+*Н0vН3ЧН6r Н=┐Н?ОB;НБ НiННйН.Н"═Н&7Н)bН+Н0[Н4 Н;Н<БН?FО@⌠НБНjНчНcНCН!9Н"wН)rН0@Н3oН:&Н=ШН?ЎО>ЛНБНzНН#Н╦Н eН#АН&дН*ЭН-²Н1иН4ЇН=нО=EНБН НаНgННtН"rН&yН(-Н*├Н.уН3≤Н7Н;fО;²НБН╗НXН╨Н Н" Н$wН(вН,\Н/8Н1іН4▄Н8#Н>/Н?╘О9ЖНБ НєНЛНґНН╣Н!ЩН%╪Н(&Н*nН-ъН2чН9Н:ЛН=4О8OНБН▒НЯНиНІННІН#@Н'MН)║Н/÷Н1NН5Н6Ґ Н=4yО6їНБxО6їН⌡yНKО6їxО6їН╛pО3XНБxО0 НєН╞Н■Н╒Н!Н"√Н%ВН+GН,ОН.│Н/▌Н3ВН8fН;" О.aНБНhНпНэНЬН Н&eН)ЎН,Н0йН3вН:lН>Н?ЎО,╨НБНфНxНрНJНвН!÷Н$;Н)Н,─Н.jyН/≥О,╨О,╨Н0╙xО,╨Н2ЙН4qН8єН:ЩН?АО+НБНЙ НЮН]НsН"TН#ЖН'gН+┌Н/╞Н2╗Н9>Н<ГО)kНБНХНQНиН┼Н"7Н&░Н(IН*╡Н-■Н0ёН46Н6<Н8╔Н>О'дНБН?Н╙ННшН┤Н!©Н%Н&mН)Н/аН1m Н;rН>┼О&НБННТНґН╠Н#ЮН'вН)┘Н-⌠Н/СН3ЪН6SpО"нНБ xО~Нє Н НН°Н#СН'ГН*хН,БН/ґН2оН8%Н=█ОвНБ Н²Н НхН#нН'йН*eН.)Н0ыН2цН8lН;(Н<пО0НБ НЗНяНNН%┘Н(Н*·Н-Ю Н4ЦН7цНОWЎНБН=НcНJНЪН Н!ЙН&Н(²Н,&Н/NН1ФН7╧Н:]ОVНБНEНYНoН nН"qН%}Н)├Н.пН0чН3PН6иН8┼Н;┼Н>ЬОToНБНєНQН)НшНФН"гН%:Н(╣Н,╘Н.kН3tН55Н:Н<▐ОRхНБНЛНKН╡Н╦Н-Н&НН,йН4uОPMНєНy ННлН ╧Н%НН'WН,SН.cН0Н2k Н9┘Н>═ОN╔НБН8Н<НSНmНтНЧН"ЄН&ЫН(ҐН+аН/vН3 Н5АН:Н;иpОKVНБxОHНєН НЪННЖН#oН%Н'^Н)kН.FН2╦Н4 Н5}Н8:Н;D ОF`НБН╞ННАНRН╞Н Н"╩Н*yН0iН8 Н@OОD╧НБН:НдН0Н┬НГН"ЛН'ґН)TН-┴Н/FН4║Н7PН9╗Н>ОCНБНUНяН+Н▄Н Н"wН'тН*. Н1$Н2┼Н9BН?ЎОAjНБНVНоН╘НeНЗН пН#■Н*DН,▐Н.ШН2qН55 ННБНЩНМНўН!┼Н)5 {О:лНБННЬН& Н╨xО7~НєН╠Н╡ Н Н%сН'sН)WН.▄Н4;Н8·Н:▄Н;КН@pО5жНБНоН7НІН IН&Н+@Н.rН4Н7ЕН=О4/НБН2ННwН|Н"JН%NН'?Н+РО1ЄНєНnН╒НКН!=Н#єН%OН'║Н.XН1Н7Н9⌡Н<хН?rО0НБ НpНFО0О0НйxО0Н╠pН▌О0О0Н ?xО0Н#ўН'ВН+7Н.▌Н23Н4Н5VН:IН=Н>jО.eНБНЎН%Н░НН7Н bН"nН&Н)ДН/MН1╡Н6НHОHНБНwНЙН|НШНлН?Н$Ь Н,√Н/TН3ШН5ЧН9╟Н=РН?ЎО║НБНXНН╣НСН Н"╡Н$XН&AН+йН/@Н0пН3hН6├Н8Н;jН>Н?ЎОЫНБН0НьННGН ;Н$ЎН'юН*2Н, Н.:Н/пН2Н3лН8rН9пН<-Н?╘О RНБНWНЄНgН?Н╡Н!Н#ЁН&нН*5О вНєН▌НзНАН!╞Н&іН*:Н,╞Н3Н7aН8╛Н< Н?юyОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡Ъ кTVm$@DRAGONMBUSSPECIFICATIONS10onethathasn'tbeenwrittenouttomemoryyet)existsinothercachesoritdoesn't.Inthefirstcasetheowner(andpossiblyothercaches)assertnMShared.TheowneralsoassertsnMAbort,preventingthememoryfromresponding,andthenproceedstosupplythequadtothemaster.Thesecondcasebreaksdownintotwosubcases.Inthefirstsubcasenoothercachehasthequad,nMShareddoesnotgetasserted,andthequadcomesfrommemory.Inthesecondsubcaseatleastoneothercachehasthedata,thenMSharedlinedoesgetasserted,butthequadstillcomesfrommemorybecausenocacheassertednMAbort.4.BusTimingThissectiongivesthedetailedtimingofbusarbitrationandofeachofthetransactionsjustdescribed.Inthetimingdiagramsusedbelow,eachrowcorrespondstoonebuscycle.ActionsduringthecycleareindicatedusingMesalikestatements.Idlebuscyclesareindicatedbyshadingasinglerowofthetimingdiagram,witheachshadedrowrepresentingzeroormorecycles.Thevariablewwillbeusedtorepresentthenumberofwaitcycles.Foreachofthedescriptionsbelow,cycle0willbethecycleinwhichtherequestorassertsMRq.Forsimplicity,thetimingsforeachofthetransactionswillassumetheminimumarbitrationdelayofzerocycles.4.1ArbitrationThetimingforarbitrationappearsinFigure2.ArequestorassertsMRqduringphaseBofcycle0.ThearbiterlatchestherequestduringtheAofcycle1,andifthebusisfreeMGntgetsassertedintheAofcycle2.ThenewmastercandrivethebusduringtheAofcycle3.Thustheminimumarbitrationdelayisthreecycles.Ifthebusisnotfree,zeroormorewaitcyclesgetinsertedimmediatelyaftercycle1.MNewRqbehavessomewhatdifferentlythanalltheotherbuslinesasfarasmastershipisconcerned.ArequesterbecomesbusmasterwithrespecttoMNewRqduringtheBofcycle2+wwhileitacquirestherestofthebusduringtheAofcycle3+w.Conversely,itrelinquishesMNewRqduringtheBimmediatelyaftertheAduringwhichMGntfalls.TheearliestMRqcanbedeassertedisduringcycle2+w.TheearliestMGntisdeassertedinresponseisduringcycle4+w,andtheearliestanewdevicecanbecomemasterisduringcycle5+w.4.2ReadQuadFigure3showsthetimingforReadQuad.Cycles0through2aretakenupbyarbitration(recallthatweareassumingtheminimumarbitrationdelay).Thefirstcycleofthetransactioniscycle3,duringwhoseAthemastersetsMCmdAB_ReadQuad;MDataAB_RQAddress;nMShared_true;nMAbort_true.Cycle4isalwaysadeadcycle:thememorysetsMCmdAB_NoOp;slavecachessetnMSharedtofalseifthereisamatch;andaslavecachethatisowner,ifthereisanowner,setsnMAbort_false.Nexttherearew(zeroormore)waitcycles,withDRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНExО_'НБН▀НWНWН╠Н bН"уН$│Н)КН,╚Н0]Н2 Н5іН9СН;╣Н=О]НБНіНЗНгН╙НЧН!Н"FН'┬Н+Н/зН3≥Н;#Н=ПО[ьНБНҐНН÷ Н#┤Н%УН+pН.Е Н6hН9.НRОU;НБНtНПНjНФН гН#⌡Н&ХН)MН.ЗН1≈Н4Н7╞Н:lН>ЇОS⌠НБНOНqНwНCН$zzОLЖНБНЎН xОIїНєНПНюНdНЖН%aН)МН+ыН.╒ Н5≥Н8┐Н:oН=сН?ЎОGЪНБНBНц Н┬Н!7Н#vН'╟Н-kН0┤Н4кН7эН:} ОFXНБН┘Н&Н╠НИНчН#CН%≈Н(ЪН+GН10Н4нН8lН; ОD╠НБНиНoНvНьН шН"ФН(Н)EН-сН0єН2lН4шН9DН?ОC НБННмН≈Н!xН$┘Н&QН)МН.рН1ЁН6РН8}Н;1Н=+Н@oОAbНБНЮН?НlН%Н!О>ГНєН▄НЗНПН█Н$aН)Н,ЁН.%Н1 Н3;Н5ьН9┬Н;sН?ЎО=@НБНЫНJНуН ┌ Н'Н)Н.`Н0÷Н3сН5▌Н7ПН?rО;≤НБН╙Н Н_ Н#$Н&нН(├Н+┼{О6╒НБН xО4'НєНhН╞Нь Н!┴Н&│Н(Н,xН.aН/зН5шН:Н=ґО2НБНкН=НЧНxН√НvН"НН'|Н)ЦН.ЎН36Н5²Н70Н8ПН∙О/1НБН6НюН%НxНЫНіН! Н"█Н%ЪН(RН.° Н5TН8РН:RН=оО-┴НБНkНрНpНЦН_Н▀Н√Н!aН$ШН'ЭН+ЗН.KН3┴ Н;hН>╚О+БНБО)gНєН.Н│Н$ Н*эН.Н0(Н2ёН6]Н9Н-Н@pО'юНБ Н╩Н НuНУН%ГН+uН-ЪН2bН5pН:Н;ўО&НБНrНПН{НRНДН √Н$jН%ъН+aН-ЮН0═Н2xН4ЖН7╛Н<;Н>╧Н@eО$qНБНqН НіН Н'уН.`Н2ЛН5hН6О Н>БО"йНБНAНнН?НMН├О NНєН┬НGНЧН√Н!⌠ Н(CН)╪Н.9Н1╧Н6AН9&Н=ЕОїНБНq Н8Н НрН aН$УН(▀Н,≥Н/tН1ВН6лН8Н;+Н?⌠ОНБНЬНhНтНEН!╦{О НБНxО▌НН├Н╠Н╣НН"]Н$▒Н,@Н0▓Н1ҐН6ЛН8Н:bН>Н@"ОГНБ НіНтНёНйН!Н'Н)zН/п Н6■ОlНєНєН╔НAН#Н╚ Н&пН(dН,Н-ІН2OН6іН8[Н:ДН?}ОдНБН~Н╧Н%@ Н,ЧН4їН7ЮН>ЦОНБНрН НіН%НiНЮН"ФН%_Н*ГН-╒Н5}Н:MН=нОvНБННвН▌НхН2Н!еН#:Н$mН)Н+уН-Н0yН4NН7&Н8⌡Н=*Н>∙О нНБН>НН√Н(Н ?Н$-Н'┴Н+Н-GН.╨Н2'Н3эН7ыН:цН?yОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡Ъ BTVm$jDRAGONMBUSSPECIFICATIONS11theslavesettingMCmd_NoOp.Cycles5+wthrough8+waredatatransfercyclesinwhichtheslavesetsMCmdAB_DataTransport;MDataAB_data;MParity_parity.DuringtheBofcycle6+wthemastermaydropMRq,andifitdoes,thearbiterdropsMGntduringtheAof8+w.NotethattheminimumnumberofcyclesforReadQuadis6,assumingzeromemorywait.4.3WriteQuadFigure4showsthetimingforWriteQuad.Cycles0through2aredevotedtoarbitrationasusual.DuringtheAofcycle3themastersetsMCmdAB_WriteQuad;MDataAB_WQAddress;nMShared_true.Nexttherearew(zeroormore)waitcycleswherethemasterassertsMDataABandMParityandthememoryassertsMCmdAB.Cycle4+wisadatatransportcycle,withthememoryassertingMCmdABandthemasterassertingMDataAB.Duringcycle4,nMSharedissettofalseifthereisamatch,regardlessofthevaluecurrentlyassertedforMCmdAB.Cycles5+w,6+wand7+wareagaindatatransportcycleswiththememoryassertingMCmdandthemastersupplyingthedata.DuringtheBofcycle5+wthemastermaydropMRq,andifitdoes,thearbiterdropsMGntduringtheAof7+w.NotethattheminumumnumberofcyclesforWriteQuadis5.4.4WriteSingleFigure5showsthetimingforWriteSingle.Cycles0through2aredevotedtoarbitration.DuringtheBofcycle2themastermaysetMRq_false,andifitdoes,thearbiterdropsMGntduringtheAofcycle4.Cycle3isthefirsttransactioncycle.DuringphaseAthemastersetsMCmdAB_WriteSingle;MDataAB_WSAddress;andnMShared_true.DuringtheAofcycle4themastersetsMCmdAB_DataTransport;MDataAB_WSData;MParity_parity.AlsoatthistimeifthereisamatchoneormoreslavessetnMShared_false.4.5IOReadFigure6showsthetimingforIORead.Arbitrationtakesplaceduringcycles0through2.DuringtheAofcycle3themastersetsMCmdAB_IORead;MDataAB_IOAddress.ThenfollowwcyclesduringwhichtheslaveusesthebusforcommandsotherthanIODone(thesecyclesmaybeidle).Asusual,wiszeroormore.DuringtheAofcycle4+wtheslavesetsMCmdAB_IODone;andMDataAB_IOData.Cycles5+wthrough7+wmaybeidlecycles,withthemastersettingMCmdAB_NoOp.DuringtheBofcycle5+wthemastermaysetMRq_falseandifitdoes,thearbitersetsMGnt_falseduringtheAof7+w.4.6IOWriteFigure7showsthetimingforIOWrite.LikeIORead,IOWritealsoisflowcontrolledanditstimingissimilar.Cycles0through2areforarbitrationasusual.DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНExО_/НБН/Н└НьН√Н#▀Н'рН+SН0yН3ЗН6;Н9.Н>'О]┬НБНмНН╣НYН7Н&5 Н0Н8Н;ЎО[ЮНБНгН≥ННvН8Н!ЄН%PН'╦Н,1Н/>Н2≥Н6єН9dН:нН<-Н?ЎОZ9НБНSН)НbНсН"2Н#©Н%xОWЎНєН;Н*Н╙Н! Н&mН(FН,^Н.╪Н5цН7OН8ЩН?ОVНБНOОTo{ОQТНБНxОOyНєНН^НvНЮН"EН$▌ Н,їН1Н2LН7▐Н8нН;-Н@oОMяНБ НіНUОKVНєН│НЖН≈НeНМН!7Н#╛Н(1Н*ГН2Ґ Н:sОI╞НБ Н#НВН"цН&5Н)еН,Н-їН1+Н2УН7Н:Н>ОHНБН0Н▐НмН ^Н#Н(JН*ПН->Н2≥Н6вН>HОF`НБНmНяНСНПНеН!┴Н$°Н&СН,YН1ЖН8іН;VН=ўОD╧НБН⌡НAН!Н$єН&EН-Н.²Н0мН2▐Н5сН7HН:ЕНО>НБН≥НЗНPНыН8Н╘Н"Н&╦Н+)Н-┬Н/Н0нО;═НєННХНHН!Н&-Н'ФН+чН.Н5CН6ў{О6╙НБН xО4/НєННPНaНдН""Н$cН,яН1/Н2hН7єН8эН;4Н@oО2┤НБНtН5Н▌НРН єН$Н%=Н'∙Н+ЧН.ШН1Н5╪Н9=Н;МН=FН>∙О0ЮНБНAН╡Н┬НбН"2Н$▓Н&Н'вН+JО.eНєНWНiН╠НННє Н#}Н'├Н,,Н/КН1TН3▒Н7ъН:]О,ҐНБН>Нс Н&╙Н)KН1Н4√Н9HН;▓Н=Н>╚О+НБНaННфН╡Н"Ґ Н,╟Н4іН:ОН@▒О)oНБН▓Н╟Н7НгНшН*Н"╒Н#ЭН%Н)'Н+аН-tН0УН4оН6зН>√{О$xНБНxО!ЩНєННEНPНўН"Н$BН*Q Н1vН4РН8┘Н<ТН@ИО VНБНОшНєН╞НPННН оН"FН$ХН) Н,}Н4─Н:sО3НБ НxНН$Н░Н#rН'мН+фН.Н1bН4EН6░Н9Н;9О▄НБНtН█НЦНыН"цН%╨Н'·Н+░Н-■Н1~Н2ТН4RН7IН9Н=UОЕНБНTНСНЎНDНИН[Н!уН$┬Н,[Н2JН5Н<яО=НБНFНЦН%НбН"пН$кН'▄Н+ЕН/ Н1sН5МН:]О√НБНШНеН$Н░НJН!ҐН%QН'╟Н,!Н/%Н1CН5ЖН9&Н;чН=?Н>∙ООНБНAН╡НSН∙Н еН%6Н'∙Н)"Н*ш{ОЬНБНxО}НєН:Н∙НхНNН"оН%3Н+тН/*Н4ЮН:Н=rН?О жНБ НdННЖНPН╪Н%Н)wН*╛Н/ДН1Н3lН5╘ НyОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡ЪATVm$ DRAGONMBUSSPECIFICATIONS12DuringtheAofcycle3themastersetsMCmdAB_IOWrite;MDataAB_IOAddress.DuringtheAofcycle4themastersetsMDataAB_IOData.DuringthisphasetheslavesetsMCmdAB_IODoneortoNoOp.IfitsetsIODonethetransactionisover.IfIODoneisnotassertedduringcycle4thenthefollowingwcyclesareusedbytheslaveforcommandsotherthanIODone.DuringtheAofcycle5+wtheslavesetsMCmdAB_IODone.Cycles6+wthrough8+wmaybeidle,withthemastersettingMCmdAB_NoOp.DuringtheBof6+wthemastersetsMRq_false,andifitdoesthearbitersetsMGnt_falseduringtheAof8+w.AppendixA.IOAddressSpaceDefinitionTheIOaddressspaceiscarvedupintodisjoint,contiguouspieceswithatmostonedevicerespondingtoeachpiece.Currently,theonlypieceassignedbelongstotheMapprocessor.AddressrangeDevice0_2||vp||+1-1Mapprocessor(||vp||isthenumberofbitsneededtorepresentavirtualpage)DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНExО_/НєН╘НDН НН ╠Н""Н$ЎН)jН,HН4EН:sО]┬НБ Н╪Н▒НЩН√Н!\Н$шН&Н(┴Н-Н/ЁН7kН=UО[ЮНБН⌡Н∙НН▀НDН&Н+≤Н-tН/:Н4┐Н6Н7▀Н:DН?ЎОZ9НБ НчНJОW╞НєН4НєНН║Н!ФН&eН)ФН+)Н.]Н0кН6КН8{Н<─Н>БОVНБНВНpНЯНHН GН#ЪН'?Н-╠Н2⌠Н5Н6╡Н8┘Н<Н?ЎОT`НБН]ННФН#KН'╧Н+_Н0╚Н4RН7iН9mН<░Н?ЎОR╧НБНqНТНсН%(Н*Н,█Н.Н/НН3═Н6Н:╛Н=kОQНБНjН!Н┌НьН НhН!ыН$zН)╪Н,ЛН1]Н3╪Н5IН7zОJ`НБННJНАН!Н%Ц xОFЩНєНxН░НwН(Н ░Н$РН'Н)уН/ Н6Н:Н=-Н>аОEVНБН▌Нт НЯН═Н!яН&C Н,шН/;Н2VН5КН;dН@oОC╞НБНAН┬ {ОA$НБНОA$Н(╧xО>▄НБ|НО>▄xО>▄Н.yО?Нч}НkО?О?НГyНtО?О?Н╩xО>▄Н╘О>▄Н(╧Н+щН1нpН2ЬО>▄О>▄Н3▓xН4CО>▄О>▄Н4⌡Н5UН6÷Н8эН=ФН?|О<ЕНБН╚О;6Н(╧Н.ІН/ЮН4;yОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡ЪDTVm$БDRAGONMBUSSPECIFICATIONS13BusCouplerROMBootOthersInterfaceEthernetDiskInterfaceI/OprocessorVME BusCacheMap Processorwith Map CacheModuleMemoryDragon ModuleDragon ModuleIFUEUFlt. Mult.Flt. AddInstr.CacheDataCacheDragon ProcessorDragon ModuleMemoryModuleMemoryModuleControllerDisplayM BusFigure 1. A Dragon ClusterDRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНE~ЬЪЗЪН#О`ЧД$Н#О[бЧ$rН#О[·Ч $Н#О[бЧ$rН\О^fН\О\╩Н╠ОIЗЧksН#ОYeЧД$Н#ОUЧ$rН#ОUЧ$rН#ОTСЧ $НЙОVНЙОW╩Н#ОR╩ЧД$Н#ОNlЧ$rН#ОNlЧ$rН#ОNIЧ $Н\ОP┌Н ОQ·Н ОSIН[ОP┌Ч $Н?ОP╔Ч$rН[ОP╔Ч$rН[ОTСЧД$Н[ОW,Ч $Н?ОWPЧ$rН[ОWPЧ$rН[О[·ЧД$Н ОYТН ОXIН[О]вЧ $Н?О]ШЧ$rН[О]ШЧ$rН[ОbIЧД$Н О`÷Н О^ТН[ОJeН?О`Чr$Н?ОYeЧr$Н?ОR╩Чr$Н╠О]вЧr$Н╠ОW,Чr$Н╠ОP┌Чr$Н'xОbIЧД$Н'xОY┴Ч$ДН0\ОY┴Ч$ДН'xОYeЧ $Н)╠О]вН#О]вЧr$Н'xОTСЧ V$Н'xОIЗЧ$Н4нОIЗЧ$Н'xОIвЧ y$Н)╠ОOСН)╠ОNI НB$ОW,Ч$НB$ОIЗЧ$ VНMAОIЗЧ$ VНB$ОIвЧ@$НEyОOeНEyОQН;yОP┌Ч╚$Н4нОOeЧ╚$Н;yО©ЧkVґН#О уН?О°Ч!z$Н?О©Ч$rН?ОЧ!V$Н?О╧Ч!V$Н?ОjЧ$rН?ОGЧ!z$Н#О─Н?О5ЗЧ$9Н#ОNЧ$(НxОNЧ$(НЙО8Чн$Н■О83Ч$╚НЙО83Ч$╚НЙО>╨Ч╚$Н#О;dН■О;dЧ╚$Н■О0HЧ╚$Н мО эЧ$▐Н#О2│НЙО5жЧ╚$НЙО/OЧ$╚Н■О/OЧ$╚НЙО/+Чн$НxО)² НЙО,РЧ╚$НЙО&kЧ$╚Н■О&kЧ$╚НЙО&GЧн$НЙО$Ч╚$НЙО┤Ч$╚Н■О┤Ч$╚НЙОcЧн$НxО ╧НxОC,Ч▐$Н■О ╧Ч]$НxО+Ч╡$Н%?О>╨Ч╚$Н%?О83Ч$╚Н+ЙО83Ч$╚Н%?О8Чн$Н&ЙО;СН&ЙО:HН%?О3²Ч╚$Н%?О-Ч$╚Н+ЙО-Ч$╚Н%?О,РЧн$Н&ЙО0жН&ЙО/+Н■О)²Ч9$Н■ОA│Н?ОЧ$.╛Н[ОEСН?ОG·Ч!V$Н?ОРЧ!z$Н2∙ОЧ$.╛Н2∙ОjЧ$rН2∙О©Ч$rН+ЙО;dЧy$Н/@О0kЧ$Н+ЙО0HЧy$Н/@О5жЧ9$Н2∙О─ЧД$Н2∙О уЧД$Н0\О]вЧ$Н;yО<│Ч╚$НEyО=НEyО;dНB$О5жЧ@$НMAО5ЗЧ$ VНB$О5ЗЧ$ VНB$ОC,Ч$Н;yО(─Ч╚$НEyО)НEyО'dНB$О!уЧ@$НMAО!ЫЧ$ VНB$О!ЫЧ$ VНB$О/+Ч$НDКО НDКОуН=$ОН?КОcЧ▐$Н?КО1Ч$ VНOzО1Ч$ VН?КОЧ╡$Н;yО╧Чr$Н$#О*yЬЗОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡]TVm$CDRAGONMBUSSPECIFICATIONS14Figure 2. Timing for Bus Arbitrationconditionally retain bus => master: MNewRq _ TRUE; <>arbiter: MGnt _ TRUE;arbiter: latch request;requestor: Mrq _ TRUE;5+w4+w3+w2+w(w>=0)w cycles1ABABABABABAB0PhaseCycleBA<><><>DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНE~ЬЪЗЪН"xО$П$НЙО?lПWНЙОA╔НЙОJ┬НЙОLаНмО-Ч$&ЕН?О-Ч$&Е~Н [О3Н [О7│Н [О;СН [О@eНмОCчНмОE┬~Н [ОIHНО4+НО1РН ИО1dЧ:Е$НО8²НО6dН ИО5жЧ:Е$НО=НО:жН ИО:HЧ:Е$НОA│НО?HН ИО>╨Ч:Е$НОEСНОC╨Н ИОC,Ч:Е$НОJeНОH,Н ИОG·Ч:Е$Н ИОLЧ:Е$Н [ОM╨Н[ОQ·Н ■ОSвЧ>;$Н ■ОP┌Ч>;$Н?ОQ·НОL·НОNвНЙО=3НЙО8аП"НЙО4OyЬЗОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡Ъ┘TVm$ЗDRAGONMBUSSPECIFICATIONS15Figure 3. Timing for ReadQuadslave: {MCmdAB _ DataTransport; MDataAB _ RQData3; MParity _ parity} arbiter: MGnt _ FALSE;slave: {MCmdAB _ DataTransport; MDataAB _ RQData2; MParity _ parity}slave: {MCmdAB _ DataTransport; MDataAB _ RQData1; MParity _ parity}slave: {MCmdAB _ DataTransport; MDataAB _ RQData0; MParity _ parity}slave: MCmdAB _ NoOp;slave: {MCmdAB _ NoOp; match => nMShared _ FALSE; owner => nMAbort _ FALSE}master: {MCmdAB _ ReadQuad; MDataAB _ RQAddress; nMShared _ TRUE; nMAbort _ TRUE}8+w7+w6+w432w cycles(w>=0)BABABAarbiter: MGnt _ TRUE;requestor: Mrq _ TRUE;5+w1ABABABABABAB0PhaseCycleBAmaster: MRq _ FALSE;DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНE~ЬЪЗЪН!\О°Н╠О&ЫП_Н╠О+kПDН╠О/щПDН╠О4√ПDН╠О9Н╠О=3ПKН╠ОAЛПQ~Н"О%╧Н"О*+Н"О.²Н"О;СН"О@eН"ОDвН ■О8аН ■О7Н╟О,РЧ?W$~НмО-─НмО/╧Н╟О(─Ч?W$НмО)НмО+GН╟О$Ч?W$НмО$²НмО&жН╠ОFН╠ОLаН■О!ЫЧ$2НО!ЫЧ$2~Н"О3Н"ОIHНмО4+НмО1РН╟О1dЧ?W$НмО8²НмО6dН╟О5жЧ?W$НмО=НмО:жН╟О:HЧ?W$НмОA│НмО?HН╟О>╨Ч?W$НмОEСНмОC╨Н╟ОC,Ч?W$НмОJeНмОH,Н╟ОG·Ч?W$Н╟ОLЧ?W$Н"ОM╨Н"ОQ·Н[ОSвЧBґ$Н[ОP┌ЧBґ$Н ОQ·НмОL·НмОNвН╠О-КyЬЗОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡ЪЄTVm$7DRAGONMBUSSPECIFICATIONS16Figure 4. Timing for WriteQuadmaster: MDataAB _ WQData0; memory: MCmdAB _ DataTransport; slave: match => nMShared _ FALSE;master: MRq _ FALSE;master: MDataAB _ WQData1; memory: MCmdAB _ DataTransport;master: MDataAB _ WQData2; memory: MCmdAB _ DataTransport;master: MDataAB _ WQData0; memory: MCmdAB _ NoOp;master: {MCmdAB _ WriteQuad; MDataAb _ WQAddress; nMShared _ TRUE}4+ww cycles(w>=0)ABCyclePhase0BABABABABABA15+wrequestor: Mrq _ TRUE;arbiter: MGnt _ TRUE;ABAB236+w7+wmaster: MDataAB _ WQData3; memory: MCmdAB _ DataTransport; arbiter MGnt _ FALSE;DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНE~ЬЪЗЪН!\О°НxО8аПbНxО2НxО4OП=НxО/щП=НxО=zП4НxОAЛПB~НИО7│НмО=3НмО;┬~Н■ОNвН■ОL·НмОQ·Н"ОP┌ЧDФ$Н"ОSвЧDФ$Н ИОQ·НИОM╨Н wОLЧA░$Н wОG·ЧA░$Н■ОH,Н■ОJeН wОC,ЧA░$Н■ОC╨Н■ОEСН wО>╨ЧA░$Н■О?HН■ОA│Н wО:HЧA░$Н■О:жН■О=Н wО5жЧA░$Н■О6dН■О8²Н wО1dЧA░$Н■О1РН■О4+НИОIHНИО3НмО&kЧ$-░Н[О&kЧ$-░НxОLаНxОF~Н■О+GН■О)Н wО(─ЧA░$Н■О/╧Н■О-─Н wО,РЧA░$НИОDвНИО@eНИО.²НИО*+НxО+kПVyЬЗОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡~TVm$#DRAGONMBUSSPECIFICATIONS17ABCyclePhase0BABABABA1requestor: Mrq _ TRUE;arbiter: MGnt _ TRUE;23Figure 5. Timing for WriteSingle4master: MRq _ FALSE;master: {MCmdAB _ WriteSingle; MDataAB _ WSAddress; nMShared _ TRUE}master: {MCmdAB _ DataTransport; MDataAB _ WSData; MParity _ parity} slave: match => nMShared _ FALSE;DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНE~ЬЪЗЪН■ОNвН■ОL·НмОQ·Н"ОP┌ЧG$Н"ОSвЧG$Н ИОQ·НИОM╨Н wОLЧCи$Н wОG·ЧCи$Н■ОH,Н■ОJeН wОC,ЧCи$Н■ОC╨Н■ОEСН wО>╨ЧCи$Н■О?HН■ОA│Н wО:HЧCи$Н■О:жН■О=НИОIHНмО83Ч$хН[О83Ч$хНxОLаНxОF~НИОDвНИО@eН■О$²НИО<│НxОD%НxОAЛПDНxО=zПiyЬЗОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡ЪdTVm$нDRAGONMBUSSPECIFICATIONS187+w6+w32BABAarbiter: MGnt _ TRUE;requestor: Mrq _ TRUE;5+w1ABABABABABAB0PhaseCycleBA(w>=0)w cycles4+wmaster: MRq _ FALSE;master: {MCmdAB _ IORead; MDataAB _ IOAddress}slave: {MCmdAB _ anything but IODone; M bus lines other than MCmdAB _ anything}master: MCmdAB _ NoOp;master: MCmdAB _ NoOp; arbiter MGnt _ FALSE;master: MCmdAB _ NoOp;slave: {MCmdAB _ IODone; MDataAB _ IOData}Figure 6. Timing for IOReadDRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНE~ЬЪЗЪНИО*+НИО.²НИО@eНИОDвН wО,РЧA░$Н■О-─Н■О/╧Н wО(─ЧA░$Н■О)Н■О+GНxОFНxОLаН[О&kЧ$-░НмО&kЧ$-░~НИО3НИОIHН■О4+Н■О1РН wО1dЧA░$Н■О8²Н■О6dН wО5жЧA░$Н■О=Н■О:жН wО:HЧA░$Н■ОA│Н■О?HН wО>╨ЧA░$Н■ОEСН■ОC╨Н wОC,ЧA░$Н■ОJeН■ОH,Н wОG·ЧA░$Н wОLЧA░$НИОM╨Н ИОQ·Н"ОSвЧDФ$Н"ОP┌ЧDФ$НмОQ·Н■ОL·Н■ОNвНмО;┬НмО=3~НИО7│НxО2НxОAЛП.НxО=аПOНxО0$НxО+kП/НxО4OНxО9П*~Н!\О°yЬЗОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡ЪуTVm$"DRAGONMBUSSPECIFICATIONS197+w6+w32BABAarbiter: MGnt _ TRUE;requestor: Mrq _ TRUE;5+w1ABABABABABAB0PhaseCycleBAmaster: MCmdAB _ NoOp;Figure 7. Timing for IOWritemaster: MCmdAB _ NoOp; arbiter MGnt _ FALSE;AB8+ww cycles(w>=0)4master: {MCmdAB _ IOWrite; MDataAB _ IOAddress}slave: {MCmdAB _ anything but IODone; M bus lines other than MCmdAB _ anything}master: MDataAB _ IOData; slave: MCmdAB _ NoOp or IODone;master: MRq _ FALSE;slave: {MCmdAB _ IODone; MDataAB _ undefined}master: MCmdAB _ NoOp;DRAGONPROJECTFORINTERNALXEROXUSEONLYxОgН║yН аОgОgН!∙xН%┘ОgОgН'_yН(FОgОgН),xН*÷ОgyОgН+ftОgНE~ЬЪЗЪНИО*+НИО.²НИО@eНИОDвН wО,РЧA░$Н■О-─Н■О/╧Н wО(─ЧA░$Н■О)Н■О+GНxОFНxОLаН[О!ЫЧ$2НмО!ЫЧ$2~НИО3НИОIHН■О4+Н■О1РН wО1dЧA░$Н■О8²Н■О6dН wО5жЧA░$Н■О=Н■О:жН wО:HЧA░$Н■ОA│Н■О?HН wО>╨ЧA░$Н■ОEСН■ОC╨Н wОC,ЧA░$Н■ОJeН■ОH,Н wОG·ЧA░$Н wОLЧA░$НИОM╨Н ИОQ·Н"ОSвЧDФ$Н"ОP┌ЧDФ$НмОQ·Н■ОL·Н■ОNвНxО0$~Н!\О°НxО&ЫП/~Н■О&жН■О$²Н wО$ЧA░$НИО%╧НмО8аНмО7~НИО;СНxОAЛП/НxО8аПOНxО=zП<НxО-єНxО4OП-НxО+kyЬЗОН┘Н /Н%╙Н'.Н*Н0yН4ТН7⌡TVm$7Ъ TIMESROMANЪ TIMESROMAN Ъ TIMESROMANЧФЪMATHЧ÷Ъ TIMESROMANЧ÷ Ъ TIMESROMANЧY Ъ TIMESROMANЧФЪ TIMESROMANЧ÷ЪLOGOЭЄЪ HELVETICAЧ÷ЪMATHЧФЪ HELVETICAЧ÷Ъ HELVETICAЧФЪ HELVETICAЧЪ HELVETICAЩ┘Ъ TIMESROMANЧ÷╘DХ& *" `+√2:YE ТO уX{\ `Bbne²hjРm╩pj/tr·?ЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪЪ[]<>mbusspecs.tioga$Monday, January 21, 1985 3:34 pm PST