Графичен ускорител

Synonymousgraphicsacceleratorcardgenerallyreferstographicsaccelerator

Състояние на развитие

TheearlyversionofthevideodisplayadapterreliedontheCPUtoprocessimageinformation,andtheCPUcontinuouslycalculatedthechangesofeachpixel.Informationisrequired,andthedataissenttotheframebufferofthevideocardthroughtheI/Obus.Theso-calledframebufferisamemorythatsavesscreenimagesallthetime.

Windows’graphicaluserinterfacedrasticallyincreasestheworkloadoftheCPUandI/Obus.InordertoreducetheburdenontheCPU,aconsiderableamountofgraphicsaccelerationmustbeobtained.ThesolutioncanonlybeinthevideoaccelerationcardAprocessingchipisadded,buttheCPUexecutesthegraphicsdeviceinterfacefunctioncall,andtheacceleratorcannotexecutethecall.ThegraphicsacceleratorreducestheI/ObusoftheCPU—itistousehard-wiredsomekeyGIDfunctionsofWindowsMethod.(GDIisanintegralpartofWindowstorealizethenecessarygraphicsfunctions).

Let’slookatacompleteworkprocess.TheWindowsapplicationprogramsendsagraphicsdeviceinterface(GDI),agraphicsfunctioncallrequest,andGDIrequiresthevideodrivertoperformthisfunction.Thedriversendstherequesttotheacceleratorforprocessing,andtheprocessorchiphandlesitthroughtheframebuffercontroller.Afterthescreendataiswrittentotheframebuffer,theframebuffercontrollersendsthedatatothememorydigital-to-analogconverter,wherethedataisconvertedintoananalogsignalforcontrollingtheCRT(cathoderaytube),ifthevideodrivercannotrecognizeitUponrequest,thegraphicsdeviceinterfaceusestheCPUandsystemRAMtoperformthisfunction.ThisiswhytheacceleratorcardcomeswithvariousdriverstosupportthemostpopularWindowsgraphicsapplications.

Inordertoobtainthebestdisplayconfiguration,thedrivershouldbeupdatedcontinuously.Whenaddingnewgraphicssoftwareormultimediasoftwaretothesystem,checkifthereisthelatestversionofthedriverfortheacceleratorcard.Itmaybeincludedinthesoftware.Ifnot,theycanbedownloadedfromthemanufacturer’sbulletinboardundernormalcircumstances,orcanbedownloadedfromapublicforumofanonlineservice.IfyouplantousetheacceleratorcardfromthecurrentdisplayconfigurationForreplacementandupgrade,youmustensurethatyoupurchaseacardthatcomplieswiththesystembusstandard.

Структура

Основните компоненти на графичния ускорител са технологията за графичен ускорител и произволна памет. Памет за достъп (RAM), памет с произволен достъп цифрово-аналогов преобразувател (RAMDAC), часовников синтезатор (ClockSynchesizer) и основна входно-изходна система (BIOS).

TherandomaccessmemoryRAMofthegraphicsacceleratorcanbecomposedofdynamicrandomaccessmemorychipDRAM,oritcanbecomposedofimagerandomaccessmemorychipwithbidirectionalaccessfunction,theformerischeap,Thelatterisexpensive,buttheimageaccessisfast.Thisisbecausethismemoryhasdualports,asintroducedintheimagememoryVRAM,ithastwoports,andimagedataflowsinfromoneport.VRAMcanflowoutfromtheotherendimmediately.Duringimageacceleration,thecolordataoftheimagepixelsthatflowedoutisimmediatelyconvertedintored,green,andblueintensityvoltagesthroughthedigital-to-analogconverter(RAMDAC)oftherandomaccessmemory.Thevalueissenttothemonitortoshowthecolor.

RAMDACissimilartothedigital-to-analogconverterintheattributecontrolleroftheVGAadapter.Italsocontainsacolorlook-uptable.ThroughtheimagecolordataoftheVRAM,thecorrespondingred,green,andbluedataissearchedfor.Outputthecolorvoltageofthethree-colorintensitytothedigital-to-analogconverter.

Theclocksynthesizerisusedtogeneratethesynchronizationsignalofthedisplayandtheclocksignalrelatedtothecontrol.

Thebasicinputandoutputsystem(BI0S)isthebasicinputandoutputsystemoftheimage,itsolidifiestheDOScallofmanyimagefunctions,justliketheBIOSinVGA.

функция

Withtheimprovementofpixelresolutionandcolorresolution,itisrelativelyeasytoconstructavideosystem,andthecostisnothigh.Youonlyneedtoincreasetherefreshrate.Thestoragecapacityofthebufferissufficient.However,withtheincreaseinresolution,itmeansthatthecomputationalworkloadwillincreaseexponentiallyorevendozensoftimes,andtheworkloadofgraphicscontrolisalsoincreasingrapidly.InthePCvideosubsystem,bothcalculationandcontrolarecompletedbytheCPU.Astheamountofcalculationandcontrolincreases,itmeansthattheamountofinformationdisplayedonthescreenincreases,whichcanbeinferredthattheamountofinputandoutputinformationoftheentiresystemincreases,Resultinginoftenexceedingtherangeallowedbysystemresources.

Thewaytosolvethisproblemistoconstructaself-excitedmechanismintheformofagraphicsacceleratorinthevideosystem.Here,themainpurposeofthestandardvideosystemistorefreshthebasicmanagementmechanismofthebufferProvidedtothehardware,thebasicmanagementoftherefreshbufferismainlytomanageeachpixel,somespecialpixelsorpixelgroupsusedtocontrolthegraphicsunitgraphicscomponentssuchasgraphicsacceleratorsthatdisplaygraphicsblocks,andtodrawlinesegments,arcsandManagementoffunctionssuchashigh-levelgraphicsprimitivessuchasdisplaymodules.

Throughthededicatedgraphicsco-processor,theextendedfunctionscanbedirectlyrealizedonthehardware,andtheextendedfunctionscanalsoberealizedthroughthegraphicprogramminginterfacesupportedbythehardware.Generallyspeaking,theso-calledhardwaresupportreferstothestandardmicroprocessorsupport,anditprovidessupporttogetherwiththegraphicscontrolprogramresidingintheROM.Forsuchasystem,thehigh-levelprogramminginterfaceisaveryimportantinterface,veryusefulintheconstructionofgraphicsaccelerators.

ThegraphicsacceleratormainlyreceivestheCPU’sdescriptionofprimitives(usuallycommands,functions,andparametersdescribingattributes),andperformscoordinatesystemtransformation(transformstheworldcoordinatesystemintothedevicecoordinatesystem,mainlyfloatingPointcalculation),cropping,transformationratio,colorshading,windowopening,andhiddensurfaceremovaloperations,theoutputofwhichispixeloperation,photoelementoperation,andhigh-endgraphicsacceleratorsdirectlyoutputred,greenandbluecolorsignals.

Asagraphicssystemonaworkstation,inadditiontothegraphicsaccelerator,theremustalsobeagraphicslibrarysupportedbythegraphicsaccelerator,suchas:SUN'sGX,TurboGXplus,andSPARCstationZXgraphicsacceleratorssupportthecompany'sXGLgraphicslibrary,SGI’sIndygraphicsboard,RealityEnginZ,etc.allsupportthecompany’sIRISgraphicslibraryandOPENGL.

Принципът на ускорението

Thekeydeviceofthegraphicsacceleratoristhegraphicsaccelerationchip,whichsolidifiessomecommonlyusedsoftwareforbasicdrawingfunctionsandimageprocessingfunctions.Inthischip,whenthesedrawingfunctionsaretobeused,theCPUdoesnotneedtocalculateandcallsomedrawingfunctions,butisdirectlyexecutedbytheaccelerationchip,whichcangreatlyincreasethedrawingspeed.ForVGAorSVGA,theaboveprocessItisalsonecessarytotransferimagedatabackandforthbetweentheCPUandtheadapterthroughthebus,whichdelaysthetimeevenmore.Forthegraphicsaccelerator,theaboveprocessesareallperformedintheaccelerator,andnobusoperationisperformed.Thusspeedingupgraphicsgeneration.

Thegraphicsandimagefunctionssolidifiedinthegraphicsaccelerationchipvaryfrommanufacturertomanufacturer.Forexample,thegraphicsacceleratordesignedforWindowsissuitableforprocessinggraphicscomposedofregulargraphicssuchasmoldlinesandrectangles.BecauseintheWindowswindow,thegraphicsthatyouseearemostlycomposedoftheseregulargraphics,whenusedtoaccelerateirregulargraphics,suchasthree-dimensionalpaintingisnotapplicable.

GraphicsacceleratorsarefullycompatiblewithVGAandSVGA,andtheygenerallyuseVESAbusorPCIbus.

SincetheVRAMinthegraphicsacceleratorstorestheimagedatatobedisplayed,itrepresentsthelengthofapixeldataandthenumberofcolorsthatcanbedisplayed.Therefore,dependingontheVRAMcapacityandthedisplayresolution,theThenumberofcolorsdisplayedisalsodifferent.Table3.6showstheimageresolutionsupportedbythegraphicsaccelerator,thenumberofcolorsdisplayed,andtherequiredVRAMcapacity.

Предимства

Thegraphicsacceleratorcanquicklycalculategraphicscalculations,suchasdrawingtriangles,andalsohavecalculationsforcommongraphicsandimageformats,suchasjpgdecompression,videostreamdecompression,etc.,withThecalculationofadvancedtextures,materials,andlightinggreatlyreducesthecomputationalburdenofthemainCPU,thereby"speedingup"thegraphicsandimages.

Theadvantagesofgraphicsacceleratorsareveryobvious:inadditiontotheobviousimprovementintheperformanceoftheentiregraphicssystem,italsosignificantlyreducesthepressureontheCPUduetothemanagementofmanygraphics,andsomehardwarehasreachedindependentoperationsituation.Withtheadvancedgraphicsinterface,itispossibletopreventprogrammersfromdirectlyoperatingonthevideohardware.Thiseffectivelyavoidscompatibilityissues.Inasense,thegraphicsacceleratoronlyeffectivelymeetstheneedsofthegraphicsprogramminginterface,andthegraphicsprogramminginterfaceshouldbeinstalledinthebiosfromthebeginning.

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