Choice Predictor | Compaq EV68A specs

21264/EV68A Microarchitecture

Figure 2–4 Global Predictor

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	Predictor
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Global Branch Prediction

FM-05812.AI4

Choice Predictor

The choice predictor monitors the history of the local and global predictors and chooses the best of the two predictors for a particular branch. Figure 2–5shows how the choice predictor generates its choice of the result of the local or global prediction. The 12-bit global path history (see Figure 2–4)is used to index a 4K entry table of 2-bit saturating counters. The value of the saturating counter determines the choice between the outputs of the local and global predictors.

Figure 2–5 Choice Predictor

Global

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Choice

Predictor

4K x 2

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2 1

Choice Prediction

FM-05813.AI4

2.1.1.3 Instruction-Stream Translation Buffer

The Ibox includes a 128-entry, fully-associative instruction-stream translation buffer (ITB) that is used to store recently used instruction-stream (Istream) address transla- tions and page protection information. Each of the entries in the ITB can map 1, 8, 64, or 512 contiguous 8KB pages. The allocation scheme is round-robin.

The ITB supports an 8-bit ASN and contains an ASM bit. The Icache is virtually addressed and contains the access-check information, so the ITB is accessed only for Istream references that miss in the Icache.

Istream transactions to I/O address space are UNDEFINED.

21264/EV68A Hardware Reference Manual

Internal Architecture 2–5

Image 33

Compaq EV68A specifications Choice Predictor, Instruction-Stream Translation Buffer

Contents

Compaq Computer Corporation Shrewsbury, Massachusetts Revision/Update Information 21264/EV68A Hardware Reference Manual Table of Contents Cache and External Interfaces Hardware Interface Internal Processor Registers Privileged Architecture Library Code Mffpcr Mtfpcr Initialization and Configuration Testability and Diagnostics Error Detection and Error HandlingElectrical Data Thermal Management 21264/EV68A Boundary-Scan Register Alpha Instruction Set Glossary Index 21264/EV68A-to-Bcache Pin Interface Figures 10-2 Type 2 Heat Sink Tables Xiv VDD Idcpower Page Content PrefaceAudience Documentation Included by Reference Terminology and Conventions For exampleAbbreviations W1S W1CAddresses Aligned and Unaligned Data Units Signal NamesDo Not Care External Undefined Do not care. a capital X represents any valid value Page Introduction ArchitectureIntroduction Addressing ArchitectureInteger Data Types Floating-Point Data Types 21264/EV68A Microprocessor Features 21264/EV68A Microprocessor Features 21264/EV68A Microprocessor Features Internal Architecture 21264/EV68A MicroarchitectureInternal Architecture Instruction Fetch, Issue, and Retire Unit 21264/EV68A MicroarchitectureVirtual Program Counter Logic Branch Predictor 21264/EV68A Block Diagram Global Predictor Local Predictor Instruction-Stream Translation Buffer Choice Predictor Integer Issue Queue Instruction Fetch LogicRegister Rename Maps Hwret Floating-Point Issue Queue Integer Execution Unit Exception and Interrupt LogicRetire Logic Integer Execution Unit-Clusters 0 PERR, MINxxx, MAXxxx, UNPKxx, PKxx 10Internal Architecture Floating-Point Execution Unit External Cache and System Interface Unit Onchip Caches21264/EV68A contains two onchip primary-level caches Memory Reference Unit Data Cache12Internal Architecture Pipeline Organization Pipeline OrganizationSrom Interface Miss address file MAF Dstream translation buffer DTB Stage 0 Instruction Fetch Stage 1 Instruction Slot14Internal Architecture Stage 2 Map Stage 3 Issue Instruction Issue Rules Instruction Issue RulesPipeline Aborts Ebox and Fbox pipelines begin execution Instruction Name, Pipeline, and Types Instruction Group Definitions FTOIS, Ftoit Ebox SlottingITOFS, ITOFF, Itoft Instruction Group Definitions and Pipeline Unit U U L E L U E E L L E U Instruction Class Latency in Cycles Instruction LatenciesHwmfpr 20Internal Architecture Instruction Retire Rules Instruction Retire RulesMinimum Retire Latencies for Instruction Classes Retire of Operate Instructions into R31/F31 Retire of Operate Instructions into R31/F31Floating-Point Divide/Square Root Early Retire BSR/JSR Load Instructions to R31 and F31 Load Instructions to R31 and F31Prefetch with Modify Intent LDS Instruction Instructions Retired Without Execution Special Cases of Alpha Instruction Execution Special Cases of Alpha Instruction ExecutionPrefetch, Evict Next LDQ and Hwldq Instructions Load Hit Speculation 10 Pipeline Timing for Floating-Point Load Instructions Floating-Point Store Instructions Cmov Instruction26Internal Architecture Memory and I/O Address Space Instructions Memory and I/O Address Space InstructionsMemory Address Space Load Instructions 2 I/O Address Space Load Instructions Memory Address Space Store Instructions Rules for I/O Address Space Load Instruction Data Merging28Internal Architecture Rules for I/O Address Space Store Instruction Data Merging 4 I/O Address Space Store Instructions MAF Memory Address Space Merging Rules Instruction OrderingMAF Memory Address Space Merging Rules Replay Traps Replay TrapsMbox Order Traps Write Buffer and the WMB Instruction 12 I/O Write Buffer and the WMB InstructionOther Mbox Replay Traps Memory Barrier MB/WMB/TB Fill Flow WMB Instruction Processing MB Instruction Processing 12 TB Fill Flow Example Sequence TB Fill Flow13 TB Fill Flow Example Sequence 34Internal Architecture Floating-Point Control Register Performance Measurement Support-Performance CountersPerformance Measurement Support-Performance Counters Floating-point control register Fpcr is shown in Figure Floating-Point Control Register 14 Floating-Point Control Register Fields36Internal Architecture Amask and Implver Instruction Values Amask and Implver Instruction Values Design Examples Design ExamplesAmask Implver 12 Typical Uniprocessor Configuration Page 21264/EV68A Microprocessor Logic Symbol Hardware InterfaceHardware Interface 21264/EV68A Microprocessor Logic Symbol 21264/EV68A Microprocessor Logic Symbol 21264/EV68A Signal Names and Functions 21264/EV68A Signal Names and FunctionsSignal Pin Types Definitions 21264/EV68A Signal Descriptions Dcokh Pllvdd TestStatH 21264/EV68A Signal Descriptions by Function SysVref Domain SysAddInL140 Pin List Sorted by Signal Name Pin AssignmentsPin Assignments AC1 Pllvdd 10Hardware Interface AA5 12Hardware Interface Pin List Sorted by PGA Location SysDataL28 14Hardware Interface BcDataH70 SysDataL5 16Hardware Interface Ground and Power VSS and VDD Pin List Mechanical Specifications Mechanical Specifications 21264/EV68A Packaging 21264/EV68A Packaging18Hardware Interface 21264/EV68A Bottom View Pin Up Page Cache and External Interfaces Introduction to the External InterfacesCache and External Interfaces Introduction to the External Interfaces 21264/EV68A System and Bcache Interfaces System Interface Physical Address Considerations Commands and AddressesPhysical Address Considerations Second-Level Cache Bcache Interface MB/WMB ECB I/O Physical Address Considerations Bcache Structure Bcache Interface SignalsBcache Structure System Duplicate Tag Stores Cache Coherency Victim Data BufferVictim Data Buffer Cache Coherency Basics Cache Block States Cache Coherency2lists the cache block states supported by the 21264/EV68A 21264/EV68A-Supported Cache Block States System Responses to 21264/EV68A Commands Mands. -4lists these commandsCache Block State Transitions Cache Block State Transitions System Responses to 21264/EV68A Commands and Reactions Using SysDc Commands 12Cache and External Interfaces Dcache States and Duplicate Tags Lock Mechanism Lock Mechanism14Cache and External Interfaces In-Order Processing of LDxL/STxC Instructions Internal Eviction of LDxL BlocksLiveness and Fairness System Port System Port16Cache and External Interfaces System Port Pins System Port Pins Programming Values for System Interface Clocks Programming the System Interface ClocksProgram Values for Data-Sample/Drive CSRs 18Cache and External Interfaces 3 21264/EV68A-to-System Commands Bank Interleave on Cache Block Boundary ModeForwarded Clocks and Frame Clock Ratio 11 Page Hit Mode of Operation Hit Mode12 21264/EV68A-to-System Command Fields Definitions 12describes the field definitions for Tables 4-10and 14describes the 21264/EV68A-to-system commands 4 21264/EV68A-to-System Commands Descriptions14 21264/EV68A-to-System Commands Descriptions 13 Maximum Physical Address for Short Bus Format 22Cache and External Interfaces 15 Programming INVALTODIRTYENABLE10 16 Programming SETDIRTYENABLE20 ProbeResponse Commands Command40 =17 21264/EV68A ProbeResponse Command 24Cache and External Interfaces SysAck and 21264/EV68A-to-System Commands Flow Control 18describes the ProbeResponse command fields18 ProbeResponse Fields Descriptions Probe Commands Four Cycles System-to-21264/EV68A Commands19 System-to-21264/EV68A Probe Commands RVB RPB 21 lists the data movement selected by Probe43 20 System-to-21264/EV68A Probe Commands Fields Descriptions22lists the next cache block state selected by Probe20 21 Data Movement Selection by Probe43 Data Transfer Commands Two Cycles 23 Data Transfer Command Format28Cache and External Interfaces 24 SysDc40 Field Description 24describes the SysDc40 field Data Movement In and Out of the 21264/EV68A 8.1 21264/EV68A Clock Basics30Cache and External Interfaces Fast Data Mode 32Cache and External Interfaces 25 Sysclk Cycles Between SysAddOut and SysData 26shows four example configurations and shows their use 26 Cbox CSR SYSDCDELAY40 ExamplesFast Data Disable Mode SysDataInValidL and SysDataOutValidL 27 Four Timing ExamplesSysDataInValidL 34Cache and External Interfaces SysFillValidL SysDataOutValidL Data Wrapping 28 Data Wrapping Rules36Cache and External Interfaces 30defines the interleaved scheme for the wrap order 29 System Wrap and Deliver Data30 Wrap Interleave Order 31defines the wrap order for double-pumped data trans fers Nonexistent Memory Processing31 Wrap Order for Double-Pumped Data Transfers 38Cache and External Interfaces 21264/EV68A Command NXM Address System/21264/EV68A Response 10.1 21264/EV68A Commands and System Probes Ordering of System Port Transactions40Cache and External Interfaces System Port Bcache Port Bcache Port Bcache Port Pins 36 Bcache Port Pins35 Range of Maximum Bcache Clock Ratios 44Cache and External Interfaces Bcache Clocking 37 BCCPUCLKDELAY10 Values 38 BCCLKDELAY10 ValuesSetting the Period of the Cache Clock 46Cache and External Interfaces 39 Program Values to Set the Cache Clock Period Single-Data Bcache Transactions 41 Data-Sample/Drive Cbox CSRsBcache Data Read and Tag Read Transactions 48Cache and External Interfaces Bcache Data Write Transactions When the ratio is odd, bcfrm is twice the ratio When the ratio is even, bcfrm is equal to the ratioFor example, in single-data mode Dual-data mode, bcfrm is twice the ratio Relationship Between Write-to-Read Bcwrrdbubbles and wrrd Pin DescriptionsRelationship Between Read-to-Write Bcrdwrbubbles and rdwr 50Cache and External Interfaces 43 Programming the Bcache Control Pins Bcache Control Pins44 lists the combination of control pin assertion for BcAddH234 46 Control Pin Assertion for Ramtype C 45 Control Pin Assertion for Ramtype B47 Control Pin Assertion for Ramtype D 52Cache and External Interfaces Bcache Banking Disabling the Bcache for DebuggingBcDataInClkH and BcTagInClkH Interrupts Interrupts54Cache and External Interfaces Internal Processor Registers Internal Processor Registers Mbox IPRs Ebox IPRs Ebox IPRsCycle Counter Register CC Cycle Counter Control Register Ccctl Virtual Address Control Register Vactl Virtual Address Register VA2describes the Ccctl register fields Cycle Counter Control Register Fields Description 3describes the virtual address control register fields Virtual Address Format Register VaformVirtual Address Control Register Fields Description VAFORM32 Ibox IPRs Ibox IPRsITB Tag Array Write Register Itbtag ITB PTE Array Write Register Itbpte ITB Invalidate All Process ASM=0 Register Itbiap ITB Invalidate All Register ItbiaITB Invalidate Single Register Itbis Exception Address Register Excaddr ProfileMe PC Register Pmpc4describes the ProfileMe PC register fields ProfileMe PC Fields Description Instruction Virtual Address Format Register Ivaform Interrupt Enable and Current Processor Mode Register Iercm Software Interrupt Request Register Sirr Iercm Register Fields Description10Internal Processor Registers Interrupt Summary Register Isum 6describes the software interrupt request register fieldsSoftware Interrupt Request Register Fields Description 7describes the interrupt summary register fields Hardware Interrupt Clear Register HwintclrInterrupt Summary Register Fields Description 12Internal Processor Registers 8describes the hardware interrupt clear register fields Exception Summary Register ExcsumHardware Interrupt Clear Register Fields Description Mchkd W1C 9describes the exception summary register fields Exception Summary Register Fields Description14Internal Processor Registers Ibox Control Register Ictl PAL Base Register Palbase10describes the PAL base register fields 10 PAL Base Register Fields Description 11describes the Ibox control register fields 11 Ibox Control Register Fields Description16Internal Processor Registers STWAIT64K SingleissuehPCT1EN PCT0EN Ibox Status Register Istat Spce18Internal Processor Registers 12 Ibox Status Register Fields Description 12describes the Ibox status register fieldsMIS TRP 20Internal Processor Registers Icache Flush Register Icflush Sleep Mode Register SleepIcache Flush ASM Register Icflushasm Clear Virtual-to-Physical Map Register Clrmap 14describes the process context register fields 14 Process Context Register Fields Description22Internal Processor Registers Performance Counter Control Register Pctrctl 15describes the performance counter control register fields15 Performance Counter Control Register Fields Description Pmstalled PctxppcePmkilledbm SL0 Mbox IPRs Mbox IPRsDTB Tag Array Write Registers 0 and 1 DTBTAG0, DTBTAG1 16 Performance Counter Control Register Input Select Fields 17 DTB Alternate Processor Mode Register Fields Description DTB Alternate Processor Mode Register DtbaltmodeDTB PTE Array Write Registers 0 and 1 DTBPTE0, DTBPTE1 17describes the Dtbaltmode register fields Dstream TB Invalidate All Register Dtbia Dstream TB Invalidate All Process ASM=0 Register DtbiapDstream TB Invalidate Single Registers 0 and 1 DTBIS0,1 ALTMODE10 Memory Management Status Register Mmstat Dstream TB Address Space Number Registers 0 and 1 DTBASN0,118describes the memory management status register fields 18 Memory Management Status Register Fields Description Mbox Control Register Mctl ForACV Dcache Control Register Dcctl Erences to superpages result in access violations19describes the Mbox control register fields 19 Mbox Control Register Fields Description Dcache Status Register Dcstat 20describes the Dcache control register fields20 Dcache Control Register Fields Description Cbox CSRs and IPRs Cbox CSRs and IPRs21describes the Dcache status register fields 21 Dcache Status Register Fields Description Cbox Shift Register Cshft Cbox Data Register CdataCbox Writeonce Chain Description 22 describes the Cbox data register fields 34Internal Processor Registers 24 Cbox Writeonce Chain Order Mboxbcprbstall BCLATDATAPATTERN031 BCLATTAGPATTERN023 BCWRRDBUBBLES03 36Internal Processor Registers SYSCLKDELAY10 38Internal Processor Registers Cbox Writemany Chain Description 25 Cbox Writemany Chain Order 40Internal Processor Registers 26 Cbox Read IPR Fields Description Cbox Read Register IPR Description 0 1 1 Istreammemerr 0 1 1 Dstreammemerr Privileged Architecture Library Code PALcode DescriptionPrivileged Architecture Library Code PALmode Environment PALmode Environment Opcodes Reserved for PALcode Required PALcode Function CodesRequired PALcode Function Codes Hwld Instruction Hwst Instruction Opcodes Reserved for PALcode3describes the Hwld instruction fields Hwld Instruction Fields Descriptions Hwret Instruction 4describes the Hwst instruction fieldsHwst Instruction Fields Descriptions 5describes the Hwret instruction fields Hwmfpr and Hwmtpr InstructionsHwret Instruction Fields Descriptions Hint Internal Processor Register Access Mechanisms Internal Processor Register Access Mechanisms6describes the Hwmfpr and Hwmtpr instructions fields Hwmfpr and Hwmtpr Instructions Fields Descriptions Hardware Structure of Explicitly Written IPRs IPR Scoreboard Bits IPR Access Ordering Hardware Structure of Implicitly Written IPRsPaired Instruction Fetch Order 10Privileged Architecture Library Code PALshadow Registers PALcode Emulation of the FpcrPALshadow Registers PALcode Entry Points PALcode Entry Points PALcode Exception Entry Locations PALcode Exception Entry Points Translation Buffer TB Fill Flows Translation Buffer TB Fill FlowsDTB Fill 14Privileged Architecture Library Code Wr Data Tb missWr PTE LD-PTE, write TB 16Privileged Architecture Library Code ITB Fill Performance Counter Support Performance Counter Support Aggregate Mode Programming Guidelines General PrecautionsAggregate Mode Precautions IPRs Used for Performance Counter Support Operation 10 Aggregate Mode Returned IPR ContentsPctrctl SL0 SL1 ProfileMe Mode Programming Guidelines 11shows the counter modes that are used with Aggregate modeThis input counts Mbox replay traps 12 Cmov Decomposed 22Privileged Architecture Library Code 13 ProfileMe Mode Returned IPR Contents Inum retire delay cycles ProfileMe Counting Mode Description Cycle counting Counter Modes for ProfileMe Mode 14shows the counter modes that are used with ProfileMe mode14 ProfileMe Mode Pctrctl Input Select Fields 24Privileged Architecture Library Code Power-Up Reset Flow and the ResetL and Dcokh Pins Initialization and Configuration21264/EV68A Reset State Machine Major Operations Initialization and Configuration Constraints Power-Up Reset Flow and the ResetL and Dcokh Pins Signal Pin Reset State Power Sequencing and Reset State for Signal Pins Pllvdd Clock Forwarding and System Clock Ratio Configuration PLL Pin Signal Names and Initialization State BiST and Srom Load and the TestStatH Pin PLL Ramp Up Clock Forward Reset and System Interface Initialization Power-Up Flow Signals and Their ConstraintsEV68A Fault Reset Flow Fault Reset FlowEffect on IPRs After Fault Reset Energy Star Certification and Sleep Mode Flow Energy Star Certification and Sleep Mode Flow 10Initialization and Configuration Effect on IPRs After Transition Through Sleep Mode Warm Reset Flow Warm Reset FlowSignals and Constraints for the Sleep Mode Sequence Effect on IPRs After Warm Reset 12Initialization and Configuration Initialization Mode ProcessingArray Initialization Array Initialization Evictenable BCWRTSTS30 Bcbankenable Initialization Mode Processing 10 Internal Processor Registers at Power-Up Reset State Internal Processor Register Power-Up Reset State14Initialization and Configuration External Interface Initialization Internal Processor Register Power-Up Reset State Reset State Machine Ieee 1149.1 Test Port ResetIeee 1149.1 Test Port Reset 16Initialization and Configuration 11 21264/EV68A Reset State Machine State Descriptions Reset State Machine 18Initialization and Configuration Phase-Lock Loop PLL Functional Description Phase-Lock Loop PLL Functional DescriptionDifferential Reference Clocks PLL Output Clocks 20Initialization and Configuration Power-Up/Reset Clocking Error Detection and Error Handling 21264/EV68A Error Detection MechanismsError Detection and Error Handling Icache Data or Tag Parity Error Data Error Correction CodeDcache Tag Parity Error Data Error Correction Code Dcache Data Single-Bit Correctable ECC Error Dcache Data Single-Bit Correctable ECC ErrorLoad Instruction Dcache Duplicate Tag Parity Error Dcache Store Second ErrorDcache Store Second Error Store Instruction Quadword or Smaller Bcache Data Single-Bit Correctable ECC Error Bcache Tag Parity ErrorBcache Tag Parity Error Controlling Bcache Block Parity Calculation Dcache Fill from Bcache Bcache Data Single-Bit Correctable ECC Error Memory/System Port Single-Bit Data Correctable ECC Error Memory/System Port Single-Bit Data Correctable ECC ErrorBcache Victim Read Icache Fill from Memory Dcache Fill from Memory Bcache Data Single-Bit Correctable ECC Error on a Probe Double-Bit Fill ErrorsBcache Data Single-Bit Correctable ECC Error on a Probe Error Case Summary Error Case Summary3summarizes the various error cases and their ramifications Section D.36 Cstatdstreammemerr Mchk CstatistreammemerrCRD Cstatprobebcerr Mchk CstatistreambcdblPage Electrical Data Electrical Characteristics1lists the maximum electrical ratings for the 21264/EV68A Maximum Electrical Ratings DC Characteristics DC CharacteristicsSignal Types Idcpower Input DC Reference Pin Idcref VDD IdcpowerInput Differential Amplifier Receiver IDA Input Differential Amplifier Clock Receiver Idaclk Pin Type Open-Drain Output Driver OOD Pin Type Open-Drain Driver for Test Pins OodtpIOZ Codtp 12 Push-Pull Output Clock Driver Oppclk 11 Push-Pull Output Driver OPP AC Characteristics AC CharacteristicsAC Test Conditions TSU1 TDH2 13 AC Specifications Dcokh AC Characteristics Page Operating Temperature at Heat Sink Center Tc Operating TemperatureThermal Management That causes thermal failure Operating Temperature Θca at Various Airflows for 21264/EV68A10-2Thermal Management Heat Sink Specifications Heat Sink Specifications 10-4Thermal Management Type 2 Heat Sink Type 3 Heat Sink Thermal Design Considerations Thermal Design Considerations10-6Thermal Management Test Pins Testability and DiagnosticsDedicated Test Port Pins Testability and Diagnostics SROM/Serial Diagnostic Terminal Port SROM/Serial Diagnostic Terminal Port11-2Testability and Diagnostics Srom Load Operation Ieee 1149.1 Port Ieee 1149.1 PortIeee 1149.1 Instructions and Opcodes TestStatH Pin 11-4Testability and DiagnosticsTestStatH Pin TAP Controller State Machine Power-Up Self-Test and Initialization Power-Up Self-Test and InitializationBuilt-in Self-Test Srom Initialization Serial Instruction Cache Load Operation 11-6Testability and Diagnostics See Appendix B for a listing of the Boundary-Scan Register Icache Bit Fields in an Srom LineReferences Page Alpha Instruction Summary Alpha Instruction SetTable A-1 Instruction Format and Opcode Notation Alpha Instruction Set A-1 Alpha Instruction Summary Pcd Trap to PALcode Mbr Branch to subroutineOpr 11.24 Cmove if = zero Opr 11.46 Cmove if ≥ zero 17.010 Convert longword to quadword 15.0AF Convert Gfloating to quadword15.0BC Convert quadword to Ffloating 15.0BE Convert quadword to Gfloating 17.02E Fcmove if ≤ zero 17.02F Fcmove if zero17.02C Fcmove if zero 17.02B Fcmove if ≠ zero Opr 13.60 Multiply quadword with integer overflow enable Opr 13.40 Multiply longword with integer overflow enableOpr 1C.31 Pixel error Mem Load Sfloating Mbr 1A.2 Return from subroutine Opr 1C.36 Pack words to bytes Mfc 18.E000 Read and clearMfc 18.C000 Read process cycle counter 18.F000 Read and set Opr 10.02 Scaled add longword by Reserved Opcodes Reserved OpcodesOpcodes Reserved for Compaq Ieee Floating-Point Instructions Ieee Floating-Point InstructionsOpcodes Reserved for PALcode 18B 10B 14B 08B 00B 04B02B 06B 12B 16B VAX Floating-Point Instructions Independent Floating-Point InstructionsVAX Floating-Point Instructions Opcode Summary Opcode Summary Mem Res Mem Table A-9explains the symbols used in Table A-8Ieee floating-point instruction opcodes Floating-point operate instruction opcodes Ieee Floating-Point Conformance Ieee Floating-Point Conformance14Alpha Instruction Set Alpha Instruction Set A-15 Table A-11 Exceptional Input and Output Conditions 16Alpha Instruction Set Cmpteq Cmptun Input Cmptlt Cmptle InputAlpha Instruction Set A-17 Fbeq Fbne Fblt Fble Fbgt Fbge LDS LDT STS STT Cpys Cpysn Boundary-Scan Register 21264/EV68A Boundary-Scan Register Pllvdd Boundary-Scan Register 21264/EV68A Boundary-Scan Register B-3 421264/EV68A Boundary-Scan Register 21264/EV68A Boundary-Scan Register B-5 621264/EV68A Boundary-Scan Register 21264/EV68A Boundary-Scan Register B-7 821264/EV68A Boundary-Scan Register 21264/EV68A Boundary-Scan Register B-9 1021264/EV68A Boundary-Scan Register 21264/EV68A Boundary-Scan Register B-11 1221264/EV68A Boundary-Scan Register Serial Icache Load Predecode Values C-1 Serial Icache Load Predecode ValuesPage PALcode Restrictions and Guidelines D-1 PALcode Restrictions and Guidelines 2PALcode Restrictions and Guidelines PALcode Restrictions and Guidelines D-3 4PALcode Restrictions and Guidelines Initwritemany PALcode Restrictions and Guidelines D-5 6PALcode Restrictions and Guidelines PALcode Restrictions and Guidelines D-7 8PALcode Restrictions and Guidelines PALcode Restrictions and Guidelines D-9 Restriction 7 Replay Trap, Interrupt Code Sequence, and STF Restriction 9 PALmode Istream Address Ranges Restriction 10 Duplicate IPR Mode BitsRestriction 9 PALmode Istream Address Ranges 10PALcode Restrictions and Guidelines Restriction 11 Ibox IPR Update Synchronization Restriction 11 Ibox IPR Update SynchronizationRestriction 13 DTB Fill Flow Collision Restriction 14 Hwret Guideline 16 JSR-BAD VA Guideline 20 Ictlsbe Stream Buffer EnableRestriction 21 HWRET/STALL After Hwmtpr ASN0/ASN1 Guideline 16 JSR-BAD VA Restriction 22 HWRET/STALL After Hwmtpr IS0/IS1 Restriction 22 HWRET/STALL After Hwmtpr IS0/IS1PALcode Restrictions and Guidelines D-13 Guideline 26 Conditional Branches in PALcode Restriction 25 Hwmtpr Itbia After ResetRestriction 24 HWRET/STALL After Hwmtpr ICFLUSH, Icflushasm 14PALcode Restrictions and Guidelines Guideline 29 JSR, JMP, RET, and Jsrcor in PALcode Restriction 30 Hwmtpr and Hwmfpr to the Cbox CSRPALcode Restrictions and Guidelines D-15 16PALcode Restrictions and Guidelines Restriction 30 Hwmtpr and Hwmfpr to the Cbox CSR Restriction 32 Pctrctl Update Restriction 31 ICTLVA48 UpdateRestriction 31 ICTLVA48 Update PALcode Restrictions and Guidelines D-17 Restriction 33 Hwld Physical/Lock Use Guideline 35 Hwintclr UpdateRestriction 36 Updating Ictlsde Restriction 37 Updating VACTLVA48 PALcode Restrictions and Guidelines D-19 Restriction 40 Scrubbing a Single-Bit Error 20PALcode Restrictions and Guidelines Restriction 40 Scrubbing a Single-Bit Error Restriction 42 Updating VACTL, CCCTL, or CC IPRs Restriction 43 No Trappable Instructions Along withPALcode Restrictions and Guidelines D-21 22PALcode Restrictions and Guidelines Restriction 47 Cache Eviction for Single-Bit Cache Errors PALcode Restrictions and Guidelines D-23 Restriction 47 Cache Eviction for Single-Bit Cache Errors 24PALcode Restrictions and Guidelines 21264/EV68A-to-Bcache Pin Interface Forwarding Clock Pin GroupingsTable E-1 Bcache Forwarding Clock Pin Groupings Late-Write Non-Bursting SSRAMs Late-Write Non-Bursting SSRAMsData Pin Usage Tag Pin Usage Dual-Data Rate SSRAMs Dual-Data Rate SSRAMsTable E-4 Dual-Data Rate Ssram Data Pin Usage Trstl Table E-5 Dual-Data Rate Ssram Tag Pin Usage421264/EV68A-to-Bcache Pin Interface 21264/EV68A-to-Bcache Pin Interface E-5 Page Glossary BIU BSR Cisc CPI CmosCPU CSR Dram DMADTB DTL FET FepromFEU Fpga IDU Gclk Ipga IowbITB Jfet MBO MAFMBZ Mips Naturally Aligned MSINmos Nvram PGA PALPLA Plcc Prom PqfpRAM RAS ROM RiscRTL SAM Simm SdramSIP Sipp TTL StramUart Unaligned Uvprom UnpredictableVAF VDF Writeblock WAR Numerics Index Index-2 Index-3 Index-4 ECC Index-6 Index-7 Index-8 Index-9 Index-10 Index-11 Index-12