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ARM r1p3, R4F manual About the processor

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Introduction

1.1About the processor

The processor is a mid-range CPU for use in deeply-embedded systems.

The features of the processor include:

•An integer unit with integral EmbeddedICE-RT logic.

•High-speedAdvanced Microprocessor Bus Architecture (AMBA) Advanced eXtensible Interfaces (AXI) for Level two (L2) master and slave interfaces.

•Dynamic branch prediction with a global history buffer, and a 4-entry return stack.

•Low interrupt latency.

•Non-maskable interrupt.

•Optional Floating Point Unit (FPU). The Cortex-R4F processor is a Cortex-R4 processor that includes the FPU.

•A Harvard Level one (L1) memory system with:

—optional Tightly-Coupled Memory (TCM) interfaces with support for error correction or parity checking memories

—optional caches with support for optional error correction schemes

—optional ARMv7-R architecture Memory Protection Unit (MPU)

—optional parity and Error Checking and Correction (ECC) on all RAM blocks.

•The ability to implement and use redundant core logic, for example, in fault detection.

•An L2 memory interface:

—single 64-bit master AXI interface

—64-bit slave AXI interface to TCM RAM blocks and cache RAM blocks.

•A debug interface to a CoreSight Debug Access Port (DAP).

•A trace interface to a CoreSight ETM-R4.

•A Performance Monitoring Unit (PMU).

•A Vectored Interrupt Controller (VIC) port.

ARM DDI 0363E	Copyright © 2009 ARM Limited. All rights reserved.	1-2
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ARM r1p3, R4F manual About the processor

Contents

Cortex-R4 and Cortex-R4F Copyright 2009 ARM Limited. All rights reserved Cortex-R4 and Cortex-R4FTechnical Reference Manual Chapter Introduction Cortex-R4 and Cortex-R4F Technical Reference ManualChapter Processor Initialization, Resets, and Clocking Chapter AC Characteristics Appendix B ECC Schemes List of Tables Adfsr and Aifsr bit functions Dirty register format, with ECC 11-12 Example interlocks 14-11 Table A-18 FPU signals Table C-1 List of Figures Cache operations C7 format for Set and Way Vector Catch Register format 11-20 Feedback on PrefaceIdentifies the major revision of the product Using this bookAbout this book Product revision statusTypographical ConventionsSignals Timing diagramsOther publications Further readingThis section lists publications by ARM and by third parties ARM publicationsFeedback on this book FeedbackARM welcomes feedback on this product and its documentation Feedback on this productIntroduction About the processor About the architecture System control coprocessor on Interrupt handling on Components of the processorThis section describes the main components of the processor Debug onPrefetch unit Data Processing UnitFloating Point Unit Load/store unitTCM interfaces Instruction and data cachesMemory Protection Unit AXI slave interface Error correction and detection5 L2 AXI interfaces AXI master interfaceReal-time debug facilities DebugSystem performance monitoring ETM interfaceLow interrupt latency System control coprocessorInterrupt handling VIC portChanges Return from exception using data from the stackAPB Debug interface Processor has the following interfaces for external accessExternal interfaces of the processor APB Debug interface ETM interface Test interfaceShutdown mode Power managementRun mode Standby modeAtcm Configurable optionsConfigurable options MPU BtcmVFP FPU includedaB1TCMPCEN Configurable options at reset Feature Options RegisterAtcmpcen B0TCMPCENAtcmrmw AtcmecenB0TCMECEN B1TCMECENInstruction decode Execution pipeline stagesNames of the pipeline stages and their functions are Write-back of data from the execution pipelines First stage of data memory accessIss Execute stagesRedundant core comparison Test features Design flow Product documentation, design flow, and architectureDocumentation Architectural information Build configurationConfiguration inputs Software configurationAdvanced Microcontroller Bus Architecture protocol Processor identification Product revision informationRevision field, Debug ID Register Variant field, Main ID RegisterRevision field, Main ID Register Variant field, Debug ID RegisterExceptions on Programmer’s ModelRegisters on Program status registers onAbout the programmer’s model Thumb state Switching stateInstruction set states ARM stateOperating modes Data types Little-endian format Memory formatsByte-invariantbig-endian format Little-endian format Byte-invariant big-endian formatRegister set RegistersRegister mode identifiers Mode Mode identifier General registers and program counter N, Z, C, and V bits Program status registersIT bits Q bitGE bits J bitDNM bits Non-maskable fast interrupts on E bitA bit I and F bitsModification of PSR bits by MSR instructions PSR mode bit valuesM40 Mode Visible state registers Thumb M bitsARM DDI 0363E Exception entry and exit summary Reset on Interrupts on Aborts onExceptions Exception entry and exit summaryLeaving an exception Taking an exceptionInterrupt request ResetInterrupts Non-maskable fast interrupts Fast interrupt requestProgram status registers on Non-maskable fast interrupts Interrupt controller Interrupt entry flowchartInterrupt entry sequence Precise aborts AbortsPrefetch aborts Data abortsAborts in Strongly Ordered and Device memory Imprecise abortsSupervisor call instruction Abort handlerBreakpoint instruction Undefined instructionException vectors Acceleration of execution environments Architecture Reference Manual Unaligned and mixed-endian data access supportBig-endian instruction support Initialization on Processor Initialization, Resets, and ClockingResets on Reset modes on2 CRS InitializationCaches on TCM on 1 MPUPreloading TCMs Caches5 TCM Preloading TCMs with parity or ECC DMA into TCMWrite to TCM directly from debugger Using TCMs from reset NSYSPORESET ResetsNRESET PRESETDBGnPower-on reset Reset modesHalt operation Processor resetNormal operation Clock gating ClockingAXI interface clocking Clock gating AXI interface clockingSystem Control Coprocessor System control coprocessor functional groups About the system control coprocessorFcse PID System control coprocessor register functionsFunction Register/operation Reference to description System performance Performance monitoring System control and configurationConfiguration Region TCM control TCM StatusCache control and configuration MPU control and configurationSystem performance monitor TCM control and configurationSystem performance monitor registers System validationARM DDI 0363E RAZ System control coprocessor registersRegister allocation Number Enable Undefined MPU Region Access Read/writeUndefined MPU Region Size Read/write Control Undefined MPU Memory Region Read/writeARM DDI 0363E Count Undefined Undefined C3-c11 C12 Performance Monitor Read/writeEvent Select Read/write Unpredictable Performance Monitor Writes Context ID Read/write C14 User Enable Read/writeUndefined C1-c15 C12 C0-c15 C13 RAZ,ignore7shows the arrangement of bits in the register 2 c0, Main ID RegisterBits Field Function 3 c0, Cache Type RegisterMain ID Register bit functions TCM Type Register bit functions Bits Field Function To access the Cache Type Register, read CP15 with4 c0, TCM Type Register Cache Type Register bit functions Bits Field FunctionTCM Type Register bit functions To access the TCM Type Register, read CP15 withTo access the MPU Type Register, read CP15 with 5 c0, MPU Type Register6 c0, Multiprocessor ID Register Processor Feature RegistersC0, Processor Feature Register 0, PFR0 Processor Feature Register 1 bit functions To access the Processor Feature Register 0 read CP15 withC0, Processor Feature Register 1, PFR1 Processor Feature Register 0 bit functions3124 Reserved To access the Processor Feature Register 1 read CP15 with8 c0, Debug Feature Register Debug Feature Register 0 bit functionsC0, Memory Model Feature Register 0, MMFR0 To access the Debug Feature Register 0 read CP15 with9 c0, Auxiliary Feature Register Memory Model Feature Registers10 Memory Model Feature Register 0 bit functions C0, Memory Model Feature Register 1, MMFR111 Memory Model Feature Register 1 bit functions 16 Memory Model Feature Register 1 formatDMB C0, Memory Model Feature Register 2, MMFR2WFI 3112 Reserved C0, Memory Model Feature Register 3, MMFR313 Memory Model Feature Register 3 bit functions 14 Instruction Set Attributes Register 0 bit functions Instruction Set Attributes RegistersC0, Instruction Set Attributes Register 0, ISAR0 20 Instruction Set Attributes Register 1 format C0, Instruction Set Attributes Register 1, ISAR1Indicates support for if then instructions C0, Instruction Set Attributes Register 2, ISAR2ITE Indicates support for PSR instructions 16 Instruction Set Attributes Register 2 bit functionsPSR Thumb instruction sets C0, Instruction Set Attributes Register 3, ISAR317 Instruction Set Attributes Register 3 bit functions 23 Instruction Set Attributes Register 4 format C0, Instruction Set Attributes Register 4, ISAR418 Instruction Set Attributes Register 4 bit functions C0, Instruction Set Attributes Registers12 c0, Current Cache Size Identification Register 8KB 4KB3130 Reserved 13 c0, Current Cache Level ID Register15 c1, System Control Register 14 c0, Cache Size Selection RegisterNmfi 23 System Control Register bit functionsAFE TRE= strict alignment fault checking enabled Enables L1 data cache= data caching disabled. This is the reset value = data caching enabled24 Auxiliary Control Register bit functions Auxiliary Control RegistersC1, Auxiliary Control Register Deolp AxiscenAxiscuen DilsmDnch RsdisDbwr DlfoC15, Secondary Auxiliary Control Register 25 Secondary Auxiliary Control Register bit functions UFC DoofmacsIXC OFCAtcmecc 17 c1, Coprocessor Access RegisterPrimary input RMWENRAM1 defines the reset value Primary input RMWENRAM0 defines the reset valueAll other encodings for these FSR bits are Reserved Fault Status and Address RegistersC5, Data Fault Status Register To use the Dfsr read or write CP15 with C5, Instruction Fault Status Register28 Data Fault Status Register bit functions 29 Instruction Fault Status Register bit functions To access the Ifsr read or write CP15 withC5, Auxiliary Fault Status Registers There are two auxiliary fault status registers= Btcm C6, Data Fault Address Register30 Adfsr and Aifsr bit functions = Atcm19 c6, MPU memory region programming registers C6, Instruction Fault Address RegisterC6, MPU Region Base Address Registers C6, MPU Region Size and Enable Registers32 Region Size Register bit functions C6, MPU Region Access Control Registers158 Sub-region disable TEX 33 MPU Region Access Control Register bit functions35 MPU Memory Region Number Register bit functions 34 Access data permission bit encodingC6, MPU Memory Region Number Register UNPPoint of Unification PoU Cache operationsPoint of Coherency PoC Set and Way format Invalidate and clean operations37 Widths of the set field for L1 cache sizes Size Set 37shows the cache sizes and the resultant bit range for SetAddress format 36 Functional bits of c7 for Set and Way38 Functional bits of c7 for address format Bits Field Data Synchronization Barrier operationData Memory Barrier operation 21 c9, Btcm Region Register39 Btcm Region Register bit functions To access the Btcm Region Register, read or write CP15 with22 c9, Atcm Region Register 40 Atcm Region Register bit functions To access the Atcm Region Register, read or write CP15 with23 c9, TCM Selection Register 24 c11, Slave Port Control RegisterRAZ/UNP 25 c13, Fcse PID Register26 c13, Context ID Register 312 Reserved27 c13, Thread and Process ID Registers Ccnt overflow IRQ request C15, nVAL IRQ Enable Set RegisterValidation Registers Ccnt overflow FIQ request C15, nVAL FIQ Enable Set RegisterCcnt overflow reset request C15, nVAL Reset Enable Set RegisterC15, nVAL Debug Request Enable Set Register Ccnt overflow debug request C15, nVAL IRQ Enable Clear Register48 nVAL IRQ Enable Clear Register format C15, nVAL FIQ Enable Clear Register303 Reserved UNP or Sbzp C15, nVAL Reset Enable Clear Register51 nVAL Debug Request Enable Clear Register format C15, nVAL Debug Request Enable Clear RegisterB0000 4kB B0001 8kB B0011 16kB B0111 32kB B1111 64kB C15, nVAL Cache Size Override Register50 nVAL Cache Size Override Register 318 Reserved53 Correctable Fault Location Register cache Correctable Fault Location Register52 Correctable Fault Location Register cache C15, Build Options 2 Register To access the Build Options 1 Register, write CP15 withBuild Options Registers C15, Build Options 1 RegisterAtcmes 55 Build Options 2 RegisterNoicache NodcacheNompu BtcmesNoie NofpuAxibusparity To access the Build Options 2 Register, write CP15 withNoharderrorcach DcacheesPrefetch Unit About the prefetch unit Disabling program flow prediction Branch predictionIncorrect predictions and correction Configuring the branch predictorBranch predictor Return stack Events and Performance Monitor Event Bit position Update ValueAbout the events Event bus interface bit functionsETMEXTOUT1 ETMEXTOUT0Dual issue case B1, B2, F2 load/store, F2D Non-cacheable access on AXI master busInstruction cache access But with different attributes Dual issue case a branchTCM correctable ECC error reported by prefetch unit Yes TCM correctable ECC error reported by load/store unit YesAbout the PMU 2shows how the bit values correspond with the Pmnc Register Performance monitoring registersPerformance monitoring registers are described 1 c9, Performance Monitor Control RegisterPmnc Register bit functions 2 c9, Count Enable Set RegisterCntens Register bit functions Bits Field Function To access the Cntens Register, read or write CP15 with3 c9, Count Enable Clear Register Cntenc Register bit functions Bits Field Function To access the Cntenc Register, read or write CP15 withCycle counter enable clear 4 c9, Overflow Flag Status Register5 c9, Software Increment Register To access the Flag Register, read or write CP15 with5shows how the bit values correspond with the Flag Register 313 Reserved RAZ on reads, Sbzp on writes Increment Counter To access the Swincr Register, read or write CP15 with6 c9, Performance Counter Selection Register Swincr Register bit functions Bits Field FunctionSEL 7 c9, Cycle Count Register8 c9, Event Selection Register EVTSELx Register bit functions To access the EVTSELx Register, read or write CP15 withUseren Register bit functions 10 c9, User Enable Register9 c9, Performance Monitor Count Registers 10 Intens Register bit functions Bits Field Function 11 c9, Interrupt Enable Set RegisterCcnt overflow interrupt enable 11 Intenc Register bit functions Bits Field Function 12 c9, Interrupt Enable Clear RegisterCcnt overflow interrupt enable bit To access the Intenc Register, read or write CP15 with Use of the event bus and counters Event bus interfaceMemory Protection Unit MPU faults onMPU software-accessible registers on True Default memory mapAbout the MPU Subregions Memory regionsRegion base address Region sizeRegion Region access permissionsRegion attributes Overlapping regionsExample of using subregions Example of using regions that overlapTCM regions Background regionsMemory types Using memory typesARM DDI 0363E TEX20, C, and B encodings Description Memory Type Shareable? Region attributes1BB Cacheable memory policiesFollowing code is an example of disabling the MPU On page 7-2shows the default memory mapMPU interaction with memory system Permission fault MPU faultsBackground fault Permission fault Alignment fault Background faultOn page 4-5shows the CP15 registers that control the MPU MPU software-accessible registersLevel One Memory System About the L1 memory system L1 memory system block diagram Parity About the error detection and correction schemesParity Bit ECC on Read-Modify-Write Error checking and correctionHard errors Bit ECCCorrect-and-retry Error correctionCorrect inline MPU faults Fault handlingFaults Classes of fault that can occur areTCM external faults External faultsCache and TCM parity and ECC errors Abort exceptions Fault status informationDebug events Precise and imprecise abortsUsage models Precise abort exceptionsImprecise abort exceptions AXI Correctable errorsTypes of aborts Conditions Source Precise Fatal ARM DDI 0363E TCM attributes and permissions About the TCMsHandling TCM parity errors on Handling TCM ECC errors on Atcm and Btcm configurationTCM internal error detection and correction TCM arbitration Handling TCM parity errorsHandling TCM ECC errors TCM port protocol External TCM errorsTCM initialization AXI slave interfaces for TCMs Store buffer About the cachesStore buffer draining Cache maintenance operationsStore buffer merging Store buffer behaviorError build options Cache error detection and correctionCache parity error behavior Value Behavior Address decoder faultsHandling cache parity errors Cache ECC error behavior Value Behavior Handling cache ECC errorsErrors on evictions Errors on instruction cache readErrors on data cache read Errors on data cache writeInvalidate all instruction cache Clean data cache by set/way Tag RAM Cache RAM organizationTag RAM Dirty RAM on Data RAM onOrganization of a dirty RAM line Dirty RAMData RAM Cache sizes and tag RAM organization Tag RAM organizationNonsequential read operation performed with one RAM access Data RAM sizes without parity or ECC implemented 13 Data cache RAM bits, with parity Description 15 Data cache data RAM sizes with ECC Cache size Data RAMs Cache interaction with memory systemDisabling or enabling all of the caches Following code is an example of enabling cachesDisabling or enabling data cache Disabling or enabling error checkingDisabling or enabling instruction cache MCR p15 R0, c1 Write System Control Register Internal exclusive monitor Memory types and L1 memory system behavior Data-cache error events Error detection eventsTCM error events Instruction-cache error eventsARM DDI 0363E Level Two Interface About the L2 interface Attribute Value Comments AXI master interface1shows the AXI master interface attributes Write response Identifiers for AXI bus accessesOutstanding write/read access on different IDs Outstanding write accesses with the same IDAruserm and Awuserm encodings Eviction bufferMemory attributes Arcachem and Awcachem encodings Encoding a MeaningMemory system implications for AXI accesses Linefills on AXI master interface transfersStrongly Ordered and Device transactions on Address20 Restrictions on AXI transfersStrongly Ordered and Device transactions Non-cacheable LdrbLdrh from Strongly Ordered or Device memory Address30 LDR or LDM that transfers one registerLDM5, Strongly Ordered or Device memory Address40 LDM that transfers five registersStrh to Strongly Ordered or Device memory Address20 Strb to Strongly Ordered or Device memory Address40First Wstrbm STR or STM of one registerSTM of seven registers Non-cacheable reads LinefillsCache line write-back eviction 15 LDR or LDM1 from Non-cacheable Normal memory Address20 14 Ldrh from Non-cacheable Normal memory Address20Non-cacheable or write-through writes AXI transaction splitting 20 AXI transaction splitting, data in two cache lines Normal write mergingExample 9-1 Write merging ARM DDI 0363E AXI slave interface for cache RAMs AXI slave interfaceAXI slave control TCM parity and ECC supportCache parity and ECC support 25 AXI slave interface attributes AXI slave characteristicsEnabling or disabling AXI slave accesses 26 RAM region decode AxUSERS bit One-hot RAM select Accessing RAMs using the AXI slave interfaceTCM RAM access on Cache RAM access on RAM selected TCM RAM accessARADDRSMSB, see Table 27 TCM chip-select decode Btcm portsThis section contains the following Cache RAM accessMemory map when accessing the cache RAMs 0001 Bank 0010 0100 1000 Data RAM access0010 Bank 0100 1000 31 Cache data RAM bank/address decode Inputs ARADDRS181535 Data format, data cache, with ECC Data bit Description 34 Data format, instruction cache, with ECCTag RAM access ARM DDI 0363E 43 Dirty register format, with ECC Data bit Description Dirty RAM accessARADDRS1815 = 4b1111 Other examples of accessing cache RAMsAbout power control on Power management on Power ControlAbout power control Shutdown mode Run modeStandby mode Dormant modeCommunication to the Power Management Controller Debug state on Cache debug on DebugProtocol converter Debug systemsDebug host Protocol converter Debug target Debug hostProgramming the debug unit About the debug unitHalting debug-mode debugging Monitor debug-mode debuggingAll other state information associated with the debug unit Coprocessor registers summary 11.3.2 CP14 access permissionsDebug register interface Coprocessor registersDebug memory-mapped registers Offset Register Access Mnemonic Description Hex NumberMemory-mapped registers Instruction Mnemonic DescriptionMemory addresses for breakpoints and watchpoints Privilege of memory access permission Power domainsEffects of resets on debug registers APB port access permissionsOther registers External debug interface access permissions RegistersLock Other Debug registers11.4.2 CP14 c0, Debug ID Register Accessing debug registersDebug register descriptions 6shows the CP14 debug register mapBRP Debug ID Register functionsWRP 11.4.4 CP14 c0, Debug Self Address Offset Register To use the Debug ID Register, read CP14 c0 with11.4.3 CP14 c0, Debug ROM Address Register To use the Debug ROM Address Register, read CP14 c0 withDebug Self Address Offset Register functions Debug Self Address Offset Register format10 Debug Status and Control Register functions 11.4.5 CP14 c1, Debug Status and Control RegisterFlag is set to 1 on entry to debug state ARM Execute ARM instruction enable bit= disabled, this is the reset value MOE DTR access modeData Transfer Register Reserved RAZ Watchpoint Fault Address Register12 Watchpoint Fault Address Register functions Vector Catch RegisterSVC 14 Debug State Cache Control Register functions Bits Field Reset Description ValueDebug State Cache Control Register Instruction Transfer Register315 Reserved Debug Run Control Register15 Debug Run Control Register functions Breakpoint Control Registers Breakpoint Value Registers17 Breakpoint Control Registers functions BVR2220 Meaning +0 is accessedCorresponding instruction address breakpoint 18 Meaning of BVR bits19 Watchpoint Value Registers functions Bits Description Watchpoint Value RegistersWatchpoint Control Registers 20 Watchpoint Control Registers functions 11 Watchpoint Control Registers formatOperating System Lock Status Register Accessed21 OS Lock Status Register functions Authentication Status Register23 Prcr functions Device Power-down and Reset Control RegisterDevice Power-down and Reset Status Register = Dbgnopwrdwn is LOW. This is the reset value24 Prsr functions 15 Prsr formatProcessor ID Registers Management registers27 Claim Tag Set Register functions Bits Field Function Claim RegistersClaim Tag Set Register Lock Status Register Lock Access Register318 Reserved RAZ or Sbzp Claim tag clear Reset value is Claim Tag Clear Register30 Device Type Register functions Device Type RegisterDebug Identification Registers Bits Value Description 32 Fields in the Peripheral Identification RegistersField Size Description 33 Peripheral ID Register 0 functions37 Peripheral ID Register 4 functions 34 Peripheral ID Register 1 functions35 Peripheral ID Register 2 functions 36 Peripheral ID Register 3 functions1022 1020Component Identification Register 1021Software debug event Debug eventsWatchpoint debug events Halting debug eventBehavior of the processor on debug events Debug event priorityDebug exception Four CP15 registers that record abort information are 40shows the values in the link register after exceptionsFollowing sections describe Effect of debug exceptions on CP15 registers and WfarAvoiding unrecoverable states 41 Read PC value after debug state entry Debug statePrivilege on Entering debug state41 Read PC value after debug state entry Debug event Behavior of the PC and Cpsr in debug statePrivilege Accessing registers and memoryExecuting instructions in debug state Writing to the Cpsr in debug stateExceptions in debug state Coprocessor instructionsEffect of debug state on non-invasive debug Effects of debug events on processor registersLeaving debug state Precise Data abortImprecise Data Abort Imprecise Data Aborts on entry and exit from debug stateSets the DSCR1 core restarted flag to Cache coherency in debug state Cache debugThis section describes cache debug. It consists Cache pollution in debug stateExternal debug interface APB signalsMiscellaneous debug signals This section describes the miscellaneous debug signalsNon-invasive debug permitted Authentication signalsChanging the authentication signals 42 Authentication signal restrictions Dbgen aIssue an Instruction Synchronization Barrier ISB instruction Example 11-1 Executing an ARM instruction through the ITR Using the debug functionalityDebug communications channel Rules for accessing the DCCExample 11-4 Target to host data transfer host end Software access to the DCCDebugger access to the DCC Example 11-5shows the code for host-to-target data transferExample 11-6 Polling the DCC host end Programming breakpoints and watchpointsThis section describes the following operations Programming simple breakpoints and the byte address selectExample 11-7 Setting a simple breakpoint Setting a simple aligned watchpointExample 11-8 Setting a simple aligned watchpoint Setting a simple unaligned watchpointNot required Example 11-9 Setting a simple unaligned watchpoint45shows some examples Single-steppingExample 11-11 Entering debug state Debug state entryExample 11-10 Single-stepping off an instruction Example 11-12 Leaving debug state Debug state exitExample 11-13 Reading an ARM register Accessing registers and memory in debug stateThis section describes the following Reading and writing registers through the DCCExample 11-16shows the code for reading the Cpsr Reading the PC in debug stateExample 11-15shows the code to read the PC Reading the Cpsr in debug stateExample 11-17 Writing the Cpsr Example 11-19 Checking for an abort after memory accessReading memory Example 11-18shows the code for reading a byte of memoryExample 11-21 Reading a word of memory Example 11-20 Reading a block of bytes of memoryFast register read/write Example 11-22 Changing the DTR access modeExample 11-23 Reading registers in stall mode Example 11-24 Writing registers in stall modeExample 11-25 Reading a block of words of memory Fast memory read/writeExample 11-27 Reading a coprocessor register Accessing coprocessor registers11-70 Debugging systems with energy management capabilities Emulating power down11-72 FPU Programmer’s Model About the VFPv3-D16 architecture About the FPU programmer’s modelFPU functionality FPU views of the register bank General-purpose registers1shows the VFP system registers in the Cortex-R4F FPU System registersVFPv3 architecture describes the following system registers This is a change in VFPv3 compared to VFPv2 All hardware ID information is privileged access onlyFpsid is privileged access only Mvfr registers are privileged access onlyRmode Floating-Point Status and Control Register, FpscrFpscr Register bit functions DNMDNM IXE RAZ UFE OFE DZE IOE IDC Floating-Point Exception Register, FpexcLEN IDE RAZMVFR0 Register bit functions Media and VFP Feature Registers, MVFR0 and MVFR1Floating-Point Exception Register bit functions DEXFull denormal arithmetic supported for VFP MVFR1 Register bit functionsDefault NaN mode Full-compliance mode Flush-to-zero mode Default NaN modeFull-compliance mode Flush-to-zero modeNaN handling Compliance with the Ieee 754 standardComplete implementation of the Ieee 754 standard Ieee 754 standard implementation choicesCDP ComparisonsUnderflow QNaN and SNaN handlingExceptions Integration Test Registers About Integration Test Registers Programming and reading Integration Test Registers Software access using APBItmiscin Register ItctrlItetmif Itmiscout1110 Processor integration testing1312 Performing integration testing Using the Integration Test RegistersItetmif Register bit assignments Bits Name Function Itetmif Register ETM interfaceItmiscout Register bit assignments Bits Name Function Itmiscout Register Miscellaneous OutputsItmiscin Register Miscellaneous Inputs Etmextout Integration Mode Control Register ItctrlBits Name Function DbgrestartIntmode Bits Access Reset value Name Function7shows the fields of the Itctrl Register RAZ/SBZPMultiplies on Divide on Branches on Cycle Timings and Interlock BehaviorDual issue on Instruction execution overview About cycle timings and interlock behaviorDefinition of terms Following sequence where R1 is a Late Reg takes two cyclesFlag-setting instructions Conditional instructionsAssembler language syntax Takes three cycles because of the result latency of R1 Register interlock examplesInstruction Behavior Sequence Takes two cycles because there are no register dependenciesCycle counts if destination is the PC Data processing instructionsCycle counts if destination is not PC Register controlled shifts Example interlocksShifter QADD, QDADD, QSUB, and Qdsub instructions SEL Media data-processingUSAD8 instruction Sum of Absolute Differences SADInstruction sequence Behavior Result of the USAD8 instructionUmlals Multiplies14-13 Divide Example instruction Cycles Memory Comments Branches10 Branch instruction cycle timing behavior All MSR instructions to the Spsr Mode changingProcessor state updating instructions All MRS instructions13shows the cycle timing behavior for loads to the PC Single load and store instructionsExample instruction Cycles Memory Result Comments Latency Base register update13 Cycle timing behavior for loads to the PC 14-19 Load and Store Double instructions Register offset, then 3-issue cyclesWrite-back Load and Store Multiple instructionsCorrect condition prediction and incorrect Load Multiples, where the PC is in the register listCorrect condition prediction and correct Return stack prediction14-23 RFE and SRS instructions Clrex Synchronization instructionsSome instructions such as cache operations take more cycles Coprocessor instructionsPrefetch Abort Undefined Instruction SVC formerly SWIMiscellaneous instructions Serializing Floating-point register transfer instructionsBlocking and serializing 2,2 Floating-point load/store instructionsBit aligned address Not aligned4,5 2,3Floating-point single-precision data processing instructions Floating-point double-precision data processing instructions Dual issue rules Dual issueDual issue rules Permitted combinations on 28 Permitted instruction combinations Dual issue First instruction Second instruction CasePermitted combinations Case F2Db Case F2stbAny single-precision CDPi, excluding Multiply-accumulate instructionsoProcessor timing on Processor timing parameters on AC CharacteristicsProcessor timing Clock uncertainty 50% Processor timing parametersInput port timing parameters Clock uncertainty 10%Clock uncertainty 60% 3shows the timing parameters for the interrupt input ports4shows the input timing parameters for the AXI master port Rreadys 5shows the input timing parameters for the AXI slave port7shows the input timing parameters for the ETM input ports 6shows the input timing parameters for the debug input portsClock uncertainty 40% 8shows the timing parameters for the test input portsClock uncertainty 65% 11shows the timing parameters for the interrupt output ports Output ports timing parametersWrite response channel Clock uncertainty 60% 13shows the timing parameters for the AXI slave output portsBRESPS10 Clock uncertainty 45% 16shows the timing parameters for the test output portsFpidc 18shows the timing parameters for the FPU output signals15-13 FPU signals on page A-23 Processor Signal DescriptionsFrom any clock About the processor signal descriptionsAny Signal Direction Clocking Description Global signalsTable A-1 Global signals Information Configuration signalsTable A-2shows the processor configuration signals Table A-2 Configuration signalsTie High for odd parity Tie LOW for even parityRMWENRAM10b Interrupt signals, including VIC interface signals AXI master port L2 interface signalsTable A-4 AXI master port signals for the L2 interface Protection signals provide addition information about a bus Identification tag for the write data group of signalsIdentification tag for the write response signal Identification tag for the read address group of signalsAXI slave port AXI master port error detection signalsTable A-5 AXI master port error detection signals Table A-6 AXI slave port signals for the L2 interfaceOne to 16. a four bit binary value minus one determines Protection information, privileged/normal access. AWPROT0AXI specification Protection information, privileged/normal access. ARPROT0Table A-7 AXI slave port error detection signals AXI slave port error detection signalsATCM, one hot. AWUSERS30 signal is not part Standard AXI specificationTable A-9shows the B0TCM port signals TCM interface signalsTable A-8shows the Atcm port signals = DMA Table A-10shows the B1TCM port signalsTable A-10 B1TCM port signals Write parity or ECC code for B1TCM B1TCM RAM access is sequentialAddress for B1TCM data RAM Write data for B1TCM data RAMTable A-11 Dual core interface signals Dual core interface signalsTable A-11shows the dual redundant core interface signals Table A-12 Debug interface signals Debug interface signalsTable A-13shows the debug miscellaneous signals Input Tie-off Debug self-address offset valid Table A-13 Debug miscellaneous signalsInput Tie-off Debug ROM physical address valid Input Tie-off Debug self-address offsetTable A-14 ETM interface signals ETM interface signalsTable A-14shows the ETM interface signals Table A-15 Test signals Test signalsTable A-15shows the test signals Table A-16shows the Mbist signals Mbist signalsTable A-17shows the validation signals Validation signalsTable A-18 FPU signals FPU signalsECC scheme selection guidelines on page B-2 ECC SchemesECC scheme selection guidelines Clarified little-endian format NCPUHALT removed from timing diagram Added sectionsRevisions Clarified byte-invariant big-endian formatChange Location Table C-1 Differences between issue B and issue CNo technical changes Table C-2 Differences between issue C and issue DBase register write-back GlossaryAbort, and an internal or External Abort See also Data Abort, External Abort and Prefetch AbortSee Advanced Microcontroller Bus Architecture See also Advanced High-performance BusSee Advanced High-performance Bus That are divisible by four and two respectivelyCompleted transfer Active read transactionActive transfer Active write transactionWrite ID width Read ID widthRead issuing capability Write ID capabilitySee also Beat See also BurstBus Accesses are expected to be word-alignedAccessed in parallel during a cache look-up See also Word-invariantSee also Dirty See also Clean See Embedded Trace Macrocell Precision and the fraction is all zeros An instruction that is architecturally UndefinedBy individual implementations Option chosen does not affect software compatibilityResult of attempting to access invalid instruction memory Serviced while normal program execution is suspendedSee also Halt mode See Cold resetSee Boundary scan chain Or equal to 1 and is not restricted to being a power of twoSee Should Be One See Should Be ZeroUser trap handler is executed See Debug test access portIncrement of +2 Destination precisionA processor Expected behavior for an unaligned accessBit for the exception is set Processor-specific. a victim is also known as a cast outCache terminology diagram