www.德州仪器.com
TMS320DM642
video/imagingfixed-pointdigitalsignalprocessor
SPRS200J–JULY2002–REVISEDAUGUST2005
thetwo.mfunctionalunitsperformallmultiplicationoperations.eachofthec64x.munitscanperform
two16×16-bitmultipliesorfour8×8-bitmultipliesperclockcycle.这.munitcanalsoperform16×
32-bitmultiplyoperations,dual16×16-bitmultiplieswithadd/subtractoperations,andquad8×8-位
multiplieswithaddoperations.inadditiontostandardmultiplies,thec64x.munitsincludebit-计数,
rotate,galoisfieldmultiplies,andbidirectionalvariableshifthardware.
thetwo.sand.lfunctionalunitsperformageneralsetofarithmetic,logical,andbranchfunctionswith
resultsavailableeveryclockcycle.thearithmeticandlogicalfunctionsonthec64xcpuincludesingle
32-位,dual16-位,andquad8-bitoperations.
theprocessingflowbeginswhena256-位-wideinstructionfetchpacketisfetchedfromaprogram
记忆.the32-bitinstructionsdestinedfortheindividualfunctionalunitsare"linked"togetherby"1"位
intheleastsignificantbit(lsb)positionoftheinstructions.theinstructionsthatare"chained"togetherfor
simultaneousexecution(uptoeightintotal)composeanexecutepacket.一个"0"inthelsbofan
instructionbreaksthechain,effectivelyplacingtheinstructionsthatfollowitinthenextexecutepacket.一个
c64x™dspdeviceenhancementnowallowsexecutepacketstocrossfetch-packetboundaries.inthe
tms320c62x™/tms320c67x™dspdevices,ifanexecutepacketcrossesthefetch-packetboundary
(256bitswide),theassemblerplacesitinthenextfetchpacket,whiletheremainderofthecurrentfetch
packetispaddedwithnopinstructions.inthec64x™dspdevice,theexecuteboundaryrestrictions
havebeenremoved,因此,eliminatingallofthenopsaddedtopadthefetchpacket,andthus,
decreasingtheoverallcodesize.thenumberofexecutepacketswithinafetchpacketcanvaryfromone
toeight.executepacketsaredispatchedtotheirrespectivefunctionalunitsattherateofoneperclock
cycleandthenext256-bitfetchpacketisnotfetcheduntilalltheexecutepacketsfromthecurrentfetch
packethavebeendispatched.afterdecoding,theinstructionssimultaneouslydriveallactivefunctional
unitsforamaximumexecutionrateofeightinstructionseveryclockcycle.whilemostresultsarestoredin
32-bitregisters,theycanbesubsequentlymovedtomemoryasbytes,half-words,ordoublewords.所有
loadandstoreinstructionsarebyte-,half-文字-,文字-,ordoubleword-addressable.
formoredetailsonthec64xcpufunctionalunitsenhancements,seethefollowingdocuments:
•
TMS320C6000CPUandInstructionSetReferenceGuide
(literaturenumberspru189)
•
TMS320C64xTechnicalOverview
(literaturenumberspru395)
8
DeviceOverview
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