Manuals / Toshiba / Computer Equipment / Computer Hardware

Toshiba TX39 user manual Reserved †, Exception program counter

Models: TX39

1 246

Download 246 pages 24.89 Kb

Page 18

Architecture

Table 2-1 lists the CP0 registers built into the R3900 Processor Core. Some of these registers are reserved

for use by an external memory management unit.

Table 2-1. List of system control coprocessor (CP0) registers

No	Mnemonic	Description

	-	(reserved) †
0
	-	(reserved) †
1
	-	(reserved) †
2
	Config††	Hardware configuration
3
	-	(reserved) †
4
	-	(reserved) †
5
	-	(reserved) †
6
	Cache††	Cache lock function
7
	BadVAddr	Last virtual address triggering error
8
	-	(reserved) †
9
10	-	(reserved) †
11	-	(reserved) †
12	Status	Information on mode, interrupt enabled, diagnostic status
13	Cause	Indicates nature of last exception
14	EPC	Exception program counter
15	PRId	Processor revision ID
16	Debug†††	Debug exception control
17	DEPC†††	Program counter for debug exception
18	-	(reserved) †

31

†Reserved for external memory management unit, when direct segment mapping MMU is not used.

††Additional R3900 Processor Core register not present in R3000A.

†††Additional R3900 Processor Core Debug register not present in R3000A.

10

Image 18

Toshiba TX39 user manual Reserved †, Exception program counter

Contents

TX39 Family Core Architecture Page Toshiba Contents EPC Exception Program Counter register Memory location of exception vectorsAppendix a Instruction Set Details Coprocessor Unusable exceptionBus Interface Unit Bus Controller / Write Buffer 229 227Bus request and bus grant 227 Cache snoop 228 230Architecture Architecture Features IntroductionHigh-performance Risc techniques Low power consumption Mathematical notation Signal notationNotation Used in This Manual Data notationArchitecture Architecture OverviewRegisters CPU registersCP0 registers Reserved † Exception program counterSource register 5 bits Instruction Set OverviewOperation code 6 bits Destination register 5 bitsJump/branch Load/storeComputational CoprocessorComputational Instructions ALU ImmediateALU 3-operand, register type Coprocessor Instructions Multiply/DivideJump/Branch Instructions Special InstructionsSpecial Instruction CP0 instructions Instruction Description CP0 InstructionsData Formats and Addressing Big endian and little endian formatsArchitecture Byte addresses of a misaligned word Pipeline Processing Overview Memory Management Unit MMU User modeKernel mode 1 R3900 Processor Core operating modesKseg0 Direct segment mappingKuseg Kseg1Address mapping Architecture Instruction Set Overview Instruction FormatsInstruction Notation Byte specifications for load and store instructions Load and Store InstructionsBase Offset Sync Computational Instructions NOR SLLV, SRLV, Srav Instruction Format and Description MFHI, Mflo Instruction Format and Description MTHI, Mtlo Instruction Format and DescriptionArchitecture Jump/Branch Instructions Jump instructionsInstruction Format and Description Instruction in the delay slot is executed during the jump 10. Branch instructionsArchitecture Special Instructions 11. Special instructionsCoprocessor Instructions COPz Instruction Format and DescriptionBCzT, BCzF Instruction Format and Description Architecture 13. System control coprocessor CP0 instructions Restore FromSystem Control Coprocessor CP0 Instructions Cache Instruction Format and DescriptionPipeline Architecture Delay Slot Delayed loadDelayed branching Nonblocking Load Function Nonblocking load functionDivide Instruction DIV, Divu StreamingMemory Management Unit MMU R3900 Processor Core Operating ModesDirect Segment Mapping Internal MMU virtual address spaceKuseg 512MB Exception Processing Utlb TLBL2 Status register Exception Processing RegistersCause register Cache registerCause register register no.13 Bits Mnemonic Field name DescriptionRead/Write ExcCode field Mnemonic CauseField name Description Status register register no.12Bits ReadStatus register 1/2 Bits Mnemonic Field name Description Value on Read NmI Non-maskable Interrupt KUc/KUp/KUo Kernel/User mode current/previous/oldIEc/IEp/IEo Interrupt Enable current/previous/old IntMask Interrupt MaskCache register register no.7 Cache registerDALc/DALp/DALo Data Cache Auto-Lock current/previous/old IAL DAL Shows how the RFE instruction works BadVAddr Bad Virtual Address register register no.8 PRId Processor Revision Identifier register register no.15Config Configuration register register no.3 21-1910. Config register2/2 Exception Details ∙ Applicable instructions Address Error exception ∙ Causes∙ Exception mask ∙ ProcessingBreakpoint exception ∙ Cause ∙ ServicingBus Error exception ∙ Causes Architecture Coprocessor Unusable exception ∙ Cause Interrupts ∙ Cause Overflow exception ∙ Cause Reserved Instruction exception ∙ CauseReset exception ∙ Cause System Call exception ∙ Cause Non-maskable interrupt ∙ CauseArchitecture Priority of Exceptions Return from Exception HandlerPriority of Exceptions Exception Mnemonic Architecture Caches Instruction CacheData cache configuration Data CacheLock bit setting Lock functionOperation during lock Lock bit clearing Auto-lock bitsCache flushing Cache Test FunctionCache disabling ExampleCache Refill Cache refillCache Snoop Architecture Debugging Functions System Control Processor CP0 RegistersPRId Processor revision ID Debug †† Debug exception control Depc ††DBD Debug Branch Delay DM Debug Mode 0 at resetDebug register register no.16 NIS Non-maskable Interrupt Status BsF Bus Error Exception FlagSSt Single at reset OES Other Exceptions StatusTypes of debug exceptions Debug ExceptionsDSS bit Debug Single Step DSSBranching to a debug exception handler Ii Debug exception handler executionIii Return from a debug exception handler Executing a Deret instructionException priorities Details of Debug Exceptions Single Step exception ∙ Cause∙ Exception masking ∙ Instruction causing this exception Debug Breakpoint exception ∙ CauseArchitecture Appendix a Instruction Set Details Instruction Classes Instruction Formats Instruction Notation Conventions Twos complement division Bitwise logical XOR operationExamples of Instruction Notation Table A-2. Common Load/Store Functions Function MeaningHalfword access 16 bits Word access 32 bitsTriplebyte access 24 bits Byte access 8 bitsJump and Branch Instructions ADD Addi Addiu Addu Rd, rs, rt Andi BCzF Operation Code Bit Encoding BCzFL 111 BCzT 113 BCzTL 115 BEQ Beql Bgez Bgezal Bgezall Bgezl Bgtz Bgtzl Blez Blezl Bltz Bltzal Bltzall Bltzl BNE Bnel Break Bit# Cache Name DataBit# Cache Operation Description Name CFCz COPz COPzCTCz Deret DIV Divu Jump JAL Jalr JR rs LB rt, offsetbase LBU LH rt, offsetbase LHU LUI LW rt, offsetbase LWL 152 LWR 154 Multiply/Add Maddu MFC0 MFCz MFCzMFCz Mfhi Mflo MTC0 MTCz MTCzMthi Mtlo Mult Multu NOR Or rd, rs, rt ORI RFE SB rt, offsetbase Sdbbp SH rt, offsetbase SLL Sllv SLT Slti Sltiu Sltu SRA Srav SRL Srlv SUB Subu SW rt, offsetbase SWL 189 SWR 191 Sync Syscall XOR Xori OPcode Special functionCOPz rs COPz rt CP0 FunctionNotation TMPR3901F 200 R3900 Processor Core On-chip peripheral circuitsBus interface for ease of system implementation Maximum operating frequency Low power consumption, optimal for portable applicationsDebugging support functions on chip PackageBus interface unit bus controller / write buffer Internal BlocksR3900 Processor Core Clock generator Address protection unit204 Configuration R3900 Processor CoreInstruction Iimitations Clock Generator Address mappingSync NOP Address Protection Unit Registers Break Address register BAddr0-1Break Mask register BMsk0-1 Break Control register BCnt0-1Break Status register BSts Memory protection exceptionRegister address map Debug Support UnitSynchronizer BSts 0xFF00 BAddr0 Bcnt0 BMsk0 BAddr1 Bcnt1 BMsk1INT* signal synchronization INT50NMI* signal synchronization CPCOND* signal synchronization CPCOND31Pins Halt signal. Indicates that TMPR3901F is in halt mode Enables internal PLL clockMode quadruple frequency of crystal oscillator Doze signal. Indicates that TMPR3901F is in doze mode∙ Master Clock OperationsClock ∙ Processor ClockMaster clock Processor System clockClock Read Operation Single ReadBus error during a single read operation Burst Read Burst read 4 words 1 wait Bus error in burst read operation 4 words Write Operation Single write operation 2 waitsInterrupts 1 NMI2 INT50 InterruptBus Arbitration Bus request and bus grantBUSGNT*L Reset Half-Speed Bus Mode Single read operation in half-speed bus modePower-Down Mode Halt mode232 Standby Mode Standby mode PLL stopDoze Mode Reduced Frequency Mode