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Toshiba TX39 user manual LH rt, offsetbase

Models: TX39

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Architecture

LH

Load Halfword

LH

	31	26 25		21 20		16 15		0
	LH			base		rt		offset
				base		rt		offset
	100001
	6			5		5		16

Format :

LH rt, offset(base)

Description :

Generates a 32-bit effective address by sign-extending the 16-bit offset and adding it to the contents of general-purpose register base. It then sign-extends the halfword at the memory location pointed to by the effective address and loads the result into general-purpose register rt.

If the effective address is not aligned on a halfword boundary, i.e., if the least significant bit of the effective address is not 0, an Address Error exception is raised.

Operation :

T:vAddr ← ((offset15)16 offset15..0) + GPR[base]

(pAddr, uncached) ← AddressTranslation (vAddr, DATA) pAddr ← pAddr31..2 (pAddr1..0 xor (ReverseEndian 0))

mem ← LoadMemory (uncached, HALFWORD, pAddr, vAddr, DATA) byte ← vAddr1..0 xor (BigEndianCPU 0)

GPR[rt] ←(mem15+8*byte)16 mem15+8*byte..8*byte

Exceptions :

UTLB Refill exception (reserved)

TLB Refill exception (reserved)

Address Error exception

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Toshiba TX39 user manual LH rt, offsetbase

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 High-performance Risc techniques FeaturesIntroduction 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 CoprocessorALU 3-operand, register type Computational InstructionsALU Immediate 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 Notation Instruction Set OverviewInstruction Formats 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 Instruction Format and Description Jump/Branch InstructionsJump instructions Instruction in the delay slot is executed during the jump 10. Branch instructionsArchitecture Special Instructions 11. Special instructionsBCzT, BCzF Instruction Format and Description Coprocessor InstructionsCOPz Instruction Format and Description Architecture 13. System control coprocessor CP0 instructions Restore FromSystem Control Coprocessor CP0 Instructions Cache Instruction Format and DescriptionPipeline Architecture Delayed branching Delay SlotDelayed load 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 registerRead/Write Cause register register no.13Bits Mnemonic Field name Description 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 Exception Mnemonic Priority of ExceptionsReturn from Exception Handler Architecture Caches Instruction CacheData cache configuration Data CacheOperation during lock Lock bit settingLock function 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 ††Debug register register no.16 DBD Debug Branch DelayDM Debug Mode 0 at reset 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 executionException priorities Iii Return from a debug exception handlerExecuting a Deret instruction ∙ Exception masking Details of Debug ExceptionsSingle Step exception ∙ Cause ∙ 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 COPz rs OPcodeSpecial function COPz rt CP0 FunctionNotation TMPR3901F 200 Bus interface for ease of system implementation R3900 Processor CoreOn-chip peripheral circuits 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 Instruction Iimitations ConfigurationR3900 Processor Core 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 ClockClock Master clock ProcessorSystem clock 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