computer architecture ele 475 / cos 475 slide deck 1

ComputerArchitectureELE475/COS475

SlideDeck1:IntroductionandInstructionSetArchitectures

DavidWentzlaffDepartmentofElectricalEngineering

PrincetonUniversity

1

WhatisComputerArchitecture?Application

2

WhatisComputerArchitecture?

Physics

Application

3

WhatisComputerArchitecture?

Physics

Application

Gaptoolargetobridgeinonestep

4

WhatisComputerArchitecture?

Initsbroadestdefinition,computerarchitectureisthedesignoftheabstraction/implementationlayersthatallowustoexecuteinformationprocessingapplicationsefficientlyusingmanufacturingtechnologies

Physics

Application

Gaptoolargetobridgeinonestep

5

WhatisComputerArchitecture?

Initsbroadestdefinition,computerarchitectureisthedesignoftheabstraction/implementationlayersthatallowustoexecuteinformationprocessingapplicationsefficientlyusingmanufacturingtechnologies

Physics

Application

Gaptoolargetobridgeinonestep

6

AbstractionsinModernComputingSystems

Physics

Devices

CircuitsGates

Register-TransferLevelMicroarchitecture

InstructionSetArchitecture

OperatingSystem/VirtualMachines

ProgrammingLanguage

Algorithm

Application

7

AbstractionsinModernComputingSystems

Physics

Devices

CircuitsGates

Register-TransferLevelMicroarchitecture

InstructionSetArchitecture

OperatingSystem/VirtualMachines

ProgrammingLanguage

Algorithm

Application

ComputerArchitecture(ELE475)

8

ComputerArchitectureisConstantlyChanging

Physics

Devices

CircuitsGates

Register-TransferLevelMicroarchitecture

InstructionSetArchitecture

OperatingSystem/VirtualMachines

ProgrammingLanguage

Algorithm

Application ApplicationRequirements:•  Suggesthowtoimprovearchitecture•  Providerevenuetofunddevelopment

TechnologyConstraints:•  Restrictwhatcanbedoneefficiently•  Newtechnologiesmakenewarch

possible

9

ComputerArchitectureisConstantlyChanging

Physics

Devices

CircuitsGates

Register-TransferLevelMicroarchitecture

InstructionSetArchitecture

OperatingSystem/VirtualMachines

ProgrammingLanguage

Algorithm

Application ApplicationRequirements:•  Suggesthowtoimprovearchitecture•  Providerevenuetofunddevelopment

TechnologyConstraints:•  Restrictwhatcanbedoneefficiently•  Newtechnologiesmakenewarch

possible

Architectureprovidesfeedbacktoguideapplicationandtechnologyresearchdirections

10

ComputersThen…

IASMachine.DesigndirectedbyJohnvonNeumann.FirstbootedinPrincetonNJin1952SmithsonianInstitutionArchives(SmithsonianImage95-06151) 11

ComputersNow

12

Robots

SupercomputersAutomobiles

Laptops

Set-topboxes

Smartphones

ServersMediaPlayers

SensorNets

Routers

CamerasGames

AudioAssistants

[fromKurzweil]

MajorTechnologyGenerations Bipolar

nMOS

CMOS

pMOS

Relays

VacuumTubes

Electromechanical

13

SequentialProcessorPerformance

14FromHennessyandPattersonEd.5ImageCopyright©2011,ElsevierInc.AllrightsReserved.

SequentialProcessorPerformance

RISC

15FromHennessyandPattersonEd.5ImageCopyright©2011,ElsevierInc.AllrightsReserved.

SequentialProcessorPerformance

RISC

Move to multi-processor

16FromHennessyandPattersonEd.5ImageCopyright©2011,ElsevierInc.AllrightsReserved.

CourseAdministrationInstructor: Prof.DavidWentzlaff(wentzlaf@princeton.edu) Office:EQuadB228

OfficeHours:Mon.1:30-2:30pmEQuadB228TA: AngLi(angl@princeton.edu)

OfficeHours:TBDEQuadF210Lectures: Monday&Wednesday11am-12:20pmEQuadB205Text: ComputerArchitecture:AQuantitativeApproach

HennesseyandPatterson,5thEdition(2012) ModernProcessorDesign:FundamentalsofSuperscalar Processors(2004) JohnP.ShenandMikkoH.Lipasti

Prerequisite: ELE375&ELE206CourseWebpage:https://eleclass.princeton.edu/classes/ele475/spring_2018/ 17

CourseStructure

•  Midterm(20%)•  FinalExam(30%)•  Labs(25%)

–  4Designlabs(Verilog)•  DesignProject(20%)

– UsingOpenPiton–  Insmallgroups

•  ClassParticipation(5%)•  UngradedProblemSets(5PS’s)(0%)

–  Veryusefulforexampreparation18

CourseContentComputerOrganization(COS/ELE375)

ComputerOrganization•  BasicPipelinedProcessor

~50,000Transistors

PhotoofBerkeleyRISCI,©UniversityofCalifornia(Berkeley)19

CourseContentComputerArchitecture(ELE475)

IntelNehalemProcessor,OriginalCorei7,ImageCreditIntel:http://download.intel.com/pressroom/kits/corei7/images/Nehalem_Die_Shot_3.jpg

20

CourseContentComputerArchitecture(ELE475)

IntelNehalemProcessor,OriginalCorei7,ImageCreditIntel:http://download.intel.com/pressroom/kits/corei7/images/Nehalem_Die_Shot_3.jpg

~700,000,000Transistors21

CourseContentComputerArchitecture(ELE475)

IntelNehalemProcessor,OriginalCorei7,ImageCreditIntel:http://download.intel.com/pressroom/kits/corei7/images/Nehalem_Die_Shot_3.jpg

~700,000,000Transistors

ComputerOrganization(ELE375)Processor

22

CourseContentComputerArchitecture(ELE475)

IntelNehalemProcessor,OriginalCorei7,ImageCreditIntel:http://download.intel.com/pressroom/kits/corei7/images/Nehalem_Die_Shot_3.jpg

~700,000,000Transistors

ComputerOrganization(ELE375)Processor

•  InstructionLevelParallelism–  Superscalar–  VeryLongInstructionWord(VLIW)

•  LongPipelines(PipelineParallelism)

•  AdvancedMemoryandCaches•  DataLevelParallelism

–  Vector–  GPU

•  ThreadLevelParallelism–  Multithreading–  Multiprocessor–  Multicore–  Manycore

23

Architecturevs.Microarchitecture

“Architecture”/InstructionSetArchitecture:•  Programmervisiblestate(Memory&Register)•  Operations(Instructionsandhowtheywork)•  ExecutionSemantics(interrupts)•  Input/Output•  DataTypes/SizesMicroarchitecture/Organization:•  TradeoffsonhowtoimplementISAforsomemetric(Speed,Energy,Cost)

•  Examples:Pipelinedepth,numberofpipelines,cachesize,siliconarea,peakpower,executionordering,buswidths,ALUwidths

24

SoftwareDevelopments

25

upto1955 Librariesofnumericalroutines-Floatingpointoperations-Transcendentalfunctions-Matrixmanipulation,equationsolvers,...

1955-60 HighlevelLanguages-Fortran1956OperatingSystems--Assemblers,Loaders,Linkers,Compilers-Accountingprogramstokeeptrackofusageandcharges

SoftwareDevelopments

26

upto1955 Librariesofnumericalroutines-Floatingpointoperations-Transcendentalfunctions-Matrixmanipulation,equationsolvers,...

1955-60 HighlevelLanguages-Fortran1956OperatingSystems--Assemblers,Loaders,Linkers,Compilers-Accountingprogramstokeeptrackofusageandcharges

Machinesrequiredexperiencedoperators•  Mostuserscouldnotbeexpectedtounderstandtheseprograms,muchlesswritethem•  Machineshadtobesoldwithalotofresidentsoftware

CompatibilityProblematIBM

27

Byearly1960’s,IBMhad4incompatiblelinesofcomputers!

701 ⇒ 7094650 ⇒ 7074702 ⇒ 70801401 ⇒ 7010

Eachsystemhaditsown• Instructionset• I/OsystemandSecondaryStorage: magnetictapes,drumsanddisks• assemblers,compilers,libraries,...• marketnichebusiness,scientific,realtime,...

CompatibilityProblematIBM

28

Byearly1960’s,IBMhad4incompatiblelinesofcomputers!

701 ⇒ 7094650 ⇒ 7074702 ⇒ 70801401 ⇒ 7010

Eachsystemhaditsown• Instructionset• I/OsystemandSecondaryStorage: magnetictapes,drumsanddisks• assemblers,compilers,libraries,...• marketnichebusiness,scientific,realtime,...

CompatibilityProblematIBM

29

Byearly1960’s,IBMhad4incompatiblelinesofcomputers!

701 ⇒ 7094650 ⇒ 7074702 ⇒ 70801401 ⇒ 7010

Eachsystemhaditsown• Instructionset• I/OsystemandSecondaryStorage: magnetictapes,drumsanddisks• assemblers,compilers,libraries,...• marketnichebusiness,scientific,realtime,...

⇒ IBM360

30

IBM360:AGeneral-PurposeRegister(GPR)Machine

• ProcessorState–  16General-Purpose32-bitRegisters

• maybeusedasindexandbaseregister• Register0hassomespecialproperties

–  4FloatingPoint64-bitRegisters–  AProgramStatusWord(PSW)

•  PC,Conditioncodes,Controlflags

•  A32-bitmachinewith24-bitaddresses–  Butnoinstructioncontainsa24-bitaddress!

•  DataFormats–  8-bitbytes,16-bithalf-words,32-bitwords,64-bitdouble-words

31

IBM360:AGeneral-PurposeRegister(GPR)Machine

• ProcessorState–  16General-Purpose32-bitRegisters

• maybeusedasindexandbaseregister• Register0hassomespecialproperties

–  4FloatingPoint64-bitRegisters–  AProgramStatusWord(PSW)

•  PC,Conditioncodes,Controlflags

•  A32-bitmachinewith24-bitaddresses–  Butnoinstructioncontainsa24-bitaddress!

•  DataFormats–  8-bitbytes,16-bithalf-words,32-bitwords,64-bitdouble-words

TheIBM360iswhybytesare8-bitslongtoday!

32

IBM360:InitialImplementations Model 30 . . . Model 70

Storage 8K - 64 KB 256K - 512 KB Datapath 8-bit 64-bit Circuit Delay 30 nsec/level 5 nsec/level Local Store Main Store Transistor Registers Control Store Read only 1µsec Conventional circuits

IBM 360 instruction set architecture (ISA) completely hid the underlying technological differences between various models. Milestone: The first true ISA designed as portable hardware-software interface!

33

IBM360:InitialImplementations Model 30 . . . Model 70

Storage 8K - 64 KB 256K - 512 KB Datapath 8-bit 64-bit Circuit Delay 30 nsec/level 5 nsec/level Local Store Main Store Transistor Registers Control Store Read only 1µsec Conventional circuits

IBM 360 instruction set architecture (ISA) completely hid the underlying technological differences between various models. Milestone: The first true ISA designed as portable hardware-software interface!

With minor modifications it still survives today!

IBM360:Over50yearslater…ThezSeriesz14Microprocessor

•  5.2GHzinIBM14nmSOICMOStechnology•  6.1billiontransistorsin696mm2•  64-bitvirtualaddressing

–  originalS/360was24-bit,andS/370was31-bitextension•  10-coredesign•  6-fetch/cycle•  10-issue/cycleout-of-ordersuperscalarpipeline•  Out-of-ordermemoryaccesses•  Redundantdatapaths

–  everyinstructionperformedintwoparalleldatapathsandresultscompared

•  128KBL1I-cache,128KBL1D-cacheon-chip•  2MBprivateI-cacheL2percore•  4MBprivateD-cacheL2percore•  On-Chip128MBeDRAML3cache•  Upto672MBeDRAML4

ImageCredit:IBMCourtesyofInternationalBusiness

MachinesCorporation,©InternationalBusinessMachinesCorporation. 34

SameArchitectureDifferentMicroarchitecture

AMDPhenomX4•  X86InstructionSet•  QuadCore•  125W•  Decode3Instructions/Cycle/Core•  64KBL1ICache,64KBL1DCache•  512KBL2Cache•  Out-of-order•  2.6GHz

IntelAtom•  X86InstructionSet•  SingleCore•  2W•  Decode2Instructions/Cycle/Core•  32KBL1ICache,24KBL1DCache•  512KBL2Cache•  In-order•  1.6GHz

ImageCredit:Intel

ImageCredit:AMD35

DifferentArchitectureDifferentMicroarchitecture

AMDPhenomX4•  X86InstructionSet•  QuadCore•  125W•  Decode3Instructions/Cycle/Core•  64KBL1ICache,64KBL1DCache•  512KBL2Cache•  Out-of-order•  2.6GHz

IBMPOWER7•  PowerInstructionSet•  EightCore•  200W•  Decode6Instructions/Cycle/Core•  32KBL1ICache,32KBL1DCache•  256KBL2Cache•  Out-of-order•  4.25GHz

ImageCredit:IBMImageCredit:AMD

CourtesyofInternationalBusinessMachinesCorporation,©InternationalBusinessMachinesCorporation.

36

WhereDoOperandsComefromAndWhereDoResultsGo?

37

WhereDoOperandsComefromAndWhereDoResultsGo?

38

ALU

WhereDoOperandsComefromAndWhereDoResultsGo?

39

ALU

…

Mem

ory

Processor

…

WhereDoOperandsComefromAndWhereDoResultsGo?

40

ALU

…

Mem

ory

WhereDoOperandsComefromAndWhereDoResultsGo?

41

WhereDoOperandsComefromAndWhereDoResultsGo?

42

…TOS

ALU

Processor

…

Mem

ory

Stack

WhereDoOperandsComefromAndWhereDoResultsGo?

43

…TOS

ALU

Processor

…

Mem

ory

ALU

Processor

…

Mem

ory

Stack Accumulator

WhereDoOperandsComefromAndWhereDoResultsGo?

44

…TOS

ALU

Processor

…

Mem

ory

ALU

Processor

…

Mem

ory

ALU

Processor

…

Mem

ory

…Stack Accumulator

Register-Memory

WhereDoOperandsComefromAndWhereDoResultsGo?

45

…TOS

ALU

Processor

…

Mem

ory

ALU

Processor

…

Mem

ory

ALU

Processor

…

Mem

ory

…Stack Accumulator

Register-Memory

Register-Register

ALU

Processor

…

Mem

ory

…

WhereDoOperandsComefromAndWhereDoResultsGo?

46

…TOS

ALU

Processor

…

Mem

ory

ALU

Processor

…

Mem

ory

ALU

Processor

…

Mem

ory

…Stack Accumulator

Register-Memory

Register-Register

0 1 2or3NumberExplicitlyNamedOperands:

ALU

Processor

…

Mem

ory

…

2or3

Stack-BasedInstructionSetArchitecture(ISA)

•  Burrough’sB5000(1960)•  Burrough’sB6700•  HP3000•  ICL2900•  Symbolics3600•  InmosTransputerModern•  Forthmachines•  JavaVirtualMachine•  Intelx87FloatingPointUnit

47

…TOS

ALU

Processor

…

Mem

ory

EvaluationofExpressions

48

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

EvaluationofExpressions

49

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

EvaluationofExpressions

50

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack

EvaluationofExpressions

51

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack push a

a

EvaluationofExpressions

52

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack a

b

EvaluationofExpressions

53

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack a

push b

b

EvaluationofExpressions

54

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack a

c b

EvaluationofExpressions

55

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack a

push c

c b

EvaluationofExpressions

56

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack a

c b

EvaluationofExpressions

57

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack a

multiply

* b * c

c b

EvaluationofExpressions

58

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

Evaluation Stack a

b * c

EvaluationofExpressions

59

a

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

add Evaluation Stack

b * c

EvaluationofExpressions

60

a

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

add

+

Evaluation Stack

b * c

EvaluationofExpressions

61

a

(a + b * c) / (a + d * c - e) /

+

* + a e

-

a c

d c

* b

Reverse Polish a b c * + a d c * + e - /

add

+

Evaluation Stack

b * c a + b * c

Hardwareorganizationofthestack

•  Stackispartoftheprocessorstate⇒ stackmustbeboundedandsmall≈ numberofRegisters,notthesizeofmainmemory

•  Conceptuallystackisunbounded

⇒apartofthestackisincludedintheprocessorstate;therestiskeptinthemainmemory

62

StackOperationsandImplicitMemoryReferences

• Supposethetop2elementsofthestackarekeptinregistersandtherestiskeptinthememory.

Eachpushoperation⇒ 1memoryreferencepopoperation ⇒ 1memoryreference

NoGood!• BetterperformancebykeepingthetopNelementsinregisters,andmemoryreferencesaremadeonlywhenregisterstackoverflowsorunderflows.

Issue-whentoLoad/Unloadregisters?

63

StackOperationsandImplicitMemoryReferences

• Supposethetop2elementsofthestackarekeptinregistersandtherestiskeptinthememory.

Eachpushoperation⇒ 1memoryreferencepopoperation ⇒ 1memoryreference

NoGood!• BetterperformancebykeepingthetopNelementsinregisters,andmemoryreferencesaremadeonlywhenregisterstackoverflowsorunderflows.

Issue-whentoLoad/Unloadregisters?

64

StackOperationsandImplicitMemoryReferences

• Supposethetop2elementsofthestackarekeptinregistersandtherestiskeptinthememory.

Eachpushoperation⇒ 1memoryreferencepopoperation ⇒ 1memoryreference

NoGood!• BetterperformancebykeepingthetopNelementsinregisters,andmemoryreferencesaremadeonlywhenregisterstackoverflowsorunderflows.

Issue-whentoLoad/Unloadregisters?

65

StackSizeandMemoryReferences

66

program stack (size = 2) memory refs push a R0 a push b R0 R1 b push c R0 R1 R2 c, ss(a) * R0 R1 sf(a) + R0 push a R0 R1 a push d R0 R1 R2 d, ss(a+b*c) push c R0 R1 R2 R3 c, ss(a) * R0 R1 R2 sf(a) + R0 R1 sf(a+b*c) push e R0 R1 R2 e,ss(a+b*c) - R0 R1 sf(a+b*c) / R0

a b c * + a d c * + e - /

StackSizeandMemoryReferences

67

program stack (size = 2) memory refs push a R0 a push b R0 R1 b push c R0 R1 R2 c, ss(a) * R0 R1 sf(a) + R0 push a R0 R1 a push d R0 R1 R2 d, ss(a+b*c) push c R0 R1 R2 R3 c, ss(a) * R0 R1 R2 sf(a) + R0 R1 sf(a+b*c) push e R0 R1 R2 e,ss(a+b*c) - R0 R1 sf(a+b*c) / R0

a b c * + a d c * + e - /

4 stores, 4 fetches (implicit)

StackSizeandExpressionEvaluation

68

program stack (size = 4) push a R0 push b R0 R1 push c R0 R1 R2 * R0 R1 + R0 push a R0 R1 push d R0 R1 R2 push c R0 R1 R2 R3 * R0 R1 R2 + R0 R1 push e R0 R1 R2 - R0 R1 / R0

a b c * + a d c * + e - /

StackSizeandExpressionEvaluation

69

program stack (size = 4) push a R0 push b R0 R1 push c R0 R1 R2 * R0 R1 + R0 push a R0 R1 push d R0 R1 R2 push c R0 R1 R2 R3 * R0 R1 R2 + R0 R1 push e R0 R1 R2 - R0 R1 / R0

a b c * + a d c * + e - /

a and c are “loaded” twice ⇒not the best use of registers!

MachineModelSummary

70

…TOS

ALU

Processor

…

Mem

ory

ALU

Processor

…Mem

ory

ALU

Processor

…

Mem

ory

…Stack Accumulator

Register-Memory

Register-Register

ALU

Processor

…

Mem

ory

…

MachineModelSummary

71

…TOS

ALU

Processor

…

Mem

ory

ALU

Processor

…Mem

ory

ALU

Processor

…

Mem

ory

…Stack Accumulator

Register-Memory

Register-Register

ALU

Processor

…

Mem

ory

…

C=A+B

MachineModelSummary

72

…TOS

ALU

Processor

…

Mem

ory

ALU

Processor

…Mem

ory

ALU

Processor

…

Mem

ory

…Stack Accumulator

Register-Memory

Register-Register

ALU

Processor

…

Mem

ory

…

C=A+B

PushAPushBAddPopC

LoadAAddBStoreC

LoadR1,AAddR3,R1,BStoreR3,C

LoadR1,ALoadR2,BAddR3,R1,R2StoreR3,C

ClassesofInstructions•  DataTransfer

–  LD,ST,MFC1,MTC1,MFC0,MTC0•  ALU

–  ADD,SUB,AND,OR,XOR,MUL,DIV,SLT,LUI•  ControlFlow

–  BEQZ,JR,JAL,TRAP,ERET•  FloatingPoint

–  ADD.D,SUB.S,MUL.D,C.LT.D,CVT.S.W,•  Multimedia(SIMD)

–  ADD.PS,SUB.PS,MUL.PS,C.LT.PS•  String

–  REPMOVSB(x86)73

AddressingModes:HowtoGetOperandsfromMemory

74

AddressingMode

Instruction Function

Register AddR4,R3,R2 Regs[R4]<-Regs[R3]+Regs[R2]**

Immediate AddR4,R3,#5 Regs[R4]<-Regs[R3]+5**

Displacement AddR4,R3,100(R1) Regs[R4]<-Regs[R3]+Mem[100+Regs[R1]]

RegisterIndirect

AddR4,R3,(R1) Regs[R4]<-Regs[R3]+Mem[Regs[R1]]

Absolute AddR4,R3,(0x475) Regs[R4]<-Regs[R3]+Mem[0x475]

MemoryIndirect

AddR4,R3,@(R1) Regs[R4]<-Regs[R3]+Mem[Mem[R1]]

PCrelative AddR4,R3,100(PC) Regs[R4]<-Regs[R3]+Mem[100+PC]

Scaled AddR4,R3,100(R1)[R5] Regs[R4]<-Regs[R3]+Mem[100+Regs[R1]+Regs[R5]*4]

**Maynotactuallyaccessmemory!

DataTypesandSizes•  Types

–  BinaryInteger–  BinaryCodedDecimal(BCD)–  FloatingPoint

•  IEEE754•  CrayFloatingPoint•  IntelExtendedPrecision(80-bit)

–  PackedVectorData–  Addresses

•  Width–  BinaryInteger(8-bit,16-bit,32-bit,64-bit)–  FloatingPoint(32-bit,40-bit,64-bit,80-bit)–  Addresses(16-bit,24-bit,32-bit,48-bit,64-bit)

75

ISAEncodingFixedWidth:EveryInstructionhassamewidth•  Easytodecode(RISCArchitectures:MIPS,PowerPC,SPARC,ARM…)Ex:MIPS,everyinstruction4-bytesVariableLength:Instructionscanvaryinwidth•  Takeslessspaceinmemoryandcaches(CISCArchitectures:IBM360,x86,Motorola68k,VAX…)Ex:x86,instructions1-byteupto17-bytesMostlyFixedorCompressed:•  Ex:MIPS16,THUMB(onlytwoformats2and4bytes)•  PowerPCandsomeVLIWs(Storeinstructionscompressed,

decompressintoInstructionCache(Very)LongInstructionWord:•  Multipleinstructionsinafixedwidthbundle•  Ex:Multiflow,HP/STLx,TIC6000 76

ISAEncodingFixedWidth:EveryInstructionhassamewidth•  Easytodecode(RISCArchitectures:MIPS,PowerPC,SPARC,ARM…)Ex:MIPS,everyinstruction4-bytesVariableLength:Instructionscanvaryinwidth•  Takeslessspaceinmemoryandcaches(CISCArchitectures:IBM360,x86,Motorola68k,VAX…)Ex:x86,instructions1-byteupto17-bytesMostlyFixedorCompressed:•  Ex:MIPS16,THUMB(onlytwoformats2and4bytes)•  PowerPCandsomeVLIWs(Storeinstructionscompressed,

decompressintoInstructionCache(Very)LongInstructionWord:•  Multipleinstructionsinafixedwidthbundle•  Ex:Multiflow,HP/STLx,TIC6000 77

x86(IA-32)InstructionEncoding

78

ImmediateDisplacementScale,Index,BaseModR/MOpcodeInstruction

Prefixes

0,1,2,or4bytes

0,1,2,or4bytes

1byte(ifneeded)

1byte(ifneeded)

1,2,or3bytes

UptofourPrefixes(1byteeach)

x86andx86-64InstructionFormatsPossibleinstructions1to18byteslong

MIPS64InstructionEncoding

79ImageCopyright©2011,ElsevierInc.AllrightsReserved.

RealWorldInstructionSets

80

Arch Type #Oper #Mem DataSize #Regs AddrSize Use

Alpha Reg-Reg 3 0 64-bit 32 64-bit Workstation

ARM Reg-Reg 3 0 32/64-bit 16 32/64-bit CellPhones,Embedded

MIPS Reg-Reg 3 0 32/64-bit 32 32/64-bit Workstation,Embedded

SPARC Reg-Reg 3 0 32/64-bit 24-32 32/64-bit Workstation

TIC6000 Reg-Reg 3 0 32-bit 32 32-bit DSP

IBM360 Reg-Mem 2 1 32-bit 16 24/31/64 Mainframe

x86 Reg-Mem 2 1 8/16/32/64-bit

4/8/24 16/32/64 PersonalComputers

VAX Mem-Mem 3 3 32-bit 16 32-bit Minicomputer

Mot.6800 Accum. 1 1/2 8-bit 0 16-bit Microcontroler

WhytheDiversityinISAs?

TechnologyInfluencedISA•  Storageisexpensive,tightencodingimportant•  ReducedInstructionSetComputer

–  Removeinstructionsuntilwholecomputerfitsondie•  Multicore/Manycore

–  TransistorsnotturningintosequentialperformanceApplicationInfluencedISA•  InstructionsforApplications

–  DSPinstructions•  CompilerTechnologyhasimproved

–  SPARCRegisterWindowsnolongerneeded–  Compilercanregisterallocateeffectively

81

Recap

82

Physics

Devices

CircuitsGates

Register-TransferLevelMicroarchitecture

InstructionSetArchitecture

OperatingSystem/VirtualMachines

ProgrammingLanguage

Algorithm

Application

ComputerArchitecture(ELE475)

Recap

•  ISAvsMicroarchitecture•  ISACharacteristics

– MachineModels–  Encoding–  DataTypes–  Instructions–  AddressingModes

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Physics

Devices

CircuitsGates

Register-TransferLevelMicroarchitecture

InstructionSetArchitecture

OperatingSystem/VirtualMachines

ProgrammingLanguage

Algorithm

Application

ComputerArchitectureLecture1

NextClass:MicrocodeandReviewofPipelining

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Acknowledgements•  Theseslidescontainmaterialdevelopedandcopyrightby:

–  Arvind(MIT)–  KrsteAsanovic(MIT/UCB)–  JoelEmer(Intel/MIT)–  JamesHoe(CMU)–  JohnKubiatowicz(UCB)–  DavidPatterson(UCB)–  ChristopherBatten(Cornell)

•  MITmaterialderivedfromcourse6.823•  UCBmaterialderivedfromcourseCS252&CS152•  CornellmaterialderivedfromcourseECE4750

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Copyright©2018DavidWentzlaff

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