IBM 750GL, 750GX 58

User’s Manual

IBM PowerPC 750GX and 750GL RISC Microprocessor

Figure 2-1. PowerPC 750GX Microprocessor Programming Model—Registers

SUPERVISOR MODEL—OEA

USER MODEL—VEA

Time Base Facility (For Reading)

TBL TBR 268		TBU	TBR 269

USER MODEL UISA

Hardware

Implementation

Registers1

HID0	SPR 1008
HID1	SPR 1009

HID2	SPR 1016

Configuration Registers

Processor			Machine
Version			State
Register			Register

PVR	SPR 287		MSR

Memory-Management Registers

		Count Register			CTR	SPR 9
			XER
			XER		XER	SPR 1

		Link Register				General Purpose
						General Purpose
		LR	SPR 8				Registers


							GPR0
							GPR1
		Condition Register

		CR					GPR31


			Performance Monitor Registers
			(For Reading)
Performance Counters1						Floating Point

Instruction BAT

Registers1

IBAT0U	SPR 528
IBAT0L	SPR 529
IBAT1U	SPR 530
IBAT1L	SPR 531
IBAT2U	SPR 532
IBAT2L	SPR 533

IBAT3U	SPR 534
IBAT3L	SPR 535
IBAT4U	SPR 560
IBAT4L	SPR 561
IBAT5U	SPR 562

IBAT5L	SPR 563

IBAT6U	SPR 564
IBAT6L	SPR 565
IBAT7U	SPR 566

IBAT7L	SPR 567

Data BAT

Registers1

DBAT0U	SPR 536
DBAT0L	SPR 537
DBAT1U	SPR 538
DBAT1L	SPR 539
DBAT2U	SPR 540
DBAT2L	SPR 541

DBAT3U	SPR 542
DBAT3L	SPR 543
DBAT4U	SPR 568
DBAT4L	SPR 569
DBAT5U	SPR 570

DBAT5L	SPR 571

DBAT6U	SPR 572
DBAT6L	SPR 573

DBAT7U	SPR 574

DBAT7L	SPR 575

Segment

Registers

SR0

SR1

SR15

SDR1

SDR1	SPR 25

Save and Restore

Registers

SRR0	SPR 26

SRR1	SPR 27

					Registers
	UPMC1	SPR 937			FPR0
	UPMC2	SPR 938			FPR0
	UPMC2	SPR 938			FPR1

	UPMC3	SPR 941
	UPMC3	SPR 941

	UPMC4	SPR 942
					FPR31
	Monitor Control1				FPR31

SPRGs

SPRG0	SPR 272
SPRG1	SPR 273
SPRG2	SPR 274
SPRG3	SPR 275

Exception Handling Registers

Data Address			DSISR
Register			DSISR SPR 18
DAR	SPR 19

UMMCR0

SPR 936

Floating-Point Status

UMMCR1

SPR 940

and Control Register

FPSCR

Sampled Instruction

Address1

USIA

SPR 939

Performance Monitor Registers

Performance

Sampled Instruction

Counters1

Address1

PMC1

SPR 953

SIA

SPR 955

PMC2

SPR 954

Monitor Control1

PMC3

SPR 957

PMC4

SPR 958

MMCR0

SPR 952

MMCR1

SPR 956

Miscellaneous Registers

External Access

Time Base

Decrementer

Register

(For Writing)

DEC

SPR 22

EAR

SPR 282

TBL

SPR 284

Instruction Address

TBU

SPR 285

Data Address

Breakpoint Register1

Breakpoint Register

L2 Control

IABR

SPR 1010

DABR

SPR 1013

Register1

L2CR

SPR 1017

Power/Thermal Management Registers

Thermal Assist Unit Registers1

Instruction-Cache Throttling

Control Register1

THRM1

SPR 1020

THRM2

SPR 1021

ICTC

SPR 1019

THRM3

SPR 1022

THRM4

SPR

920

1. These are processor-specific registers. They might not be supported by other PowerPC processors.

Programming Model	gx_02.fm.(1.2)
Page 58 of 377	March 27, 2006

Contents

Page Page List of Figures List of Tables About This Manual Page 3. Instruction-Cacheand Data-CacheOperation 4. Exceptions Page 6. Instruction Timing Page 8. Bus Interface Operation 10. Power and Thermal Management 11. Performance Monitor and System Related Features Acronyms and Abbreviations Index Revision Log Page List of Figures Page List of Tables Page Page Page About This Manual Who Should Read This Manual Related Publications Conventions Used in This Manual Terminology Conventions Instruction Field Conventions Using This Manual with the Programming Environments Manual 1. PowerPC 750GX Overview 1.1 750GX Microprocessor Overview Page 1.2 750GX Microprocessor Features Page Page Page 1.2.1 Instruction Flow 1.2.1.1 Instruction Queue and Dispatch Unit 1.2.1.2 Branch Processing Unit (BPU) bclr 1.2.1.3 Completion Unit 1.2.2 Independent Execution Units 1.2.2.1 Integer Units (IUs) 1.2.2.2 Floating-PointUnit (FPU) 1.2.2.3 Load/Store Unit (LSU) 1.2.2.4 System Register Unit (SRU) 1.2.3 Memory Management Units (MMUs) 1.2.4 On-ChipLevel 1 Instruction and Data Caches Page 1.2.5 On-ChipLevel 2 Cache Implementation 1.2.6 System Interface/Bus Interface Unit (BIU) Page 1.2.7 Signals Note 1.2.8 Signal Configuration Page 1.3 750GX Microprocessor Implementation Page 1.4 PowerPC Registers and Programming Model Page Page 1.5 Instruction Set Page 1.6 On-ChipCache Implementation 1.7 Exception Model 1.7.2 750GX Microprocessor Exception Implementation Page 1.8 Memory Management 1.9 Instruction Timing Page 1.10 Power Management 1.11 Thermal Management 1.12 Performance Monitor 2. Programming Model 2.1 PowerPC 750GX Processor Register Set Page Implementation Note: User-level registers Implementation Note lscbx Supervisor-level Page -specific Page 2.1.2 PowerPC 750GX-SpecificRegisters 2.1.2.1 Instruction Address Breakpoint Register (IABR) 2.1.2.2 Hardware-Implementation-DependentRegister 0 (HID0) Page Page Page Page 2.1.2.3 Hardware-Implementation-DependentRegister 1 (HID1) 2.1.2.4 Hardware-Implementation-DependentRegister 2 (HID2) 2.1.2.5 Performance-MonitorRegisters Page Page Page Page 2.1.3 Instruction Cache Throttling Control Register (ICTC) 2.1.4 Thermal-ManagementRegisters (THRMn) 2.1.4.1 Thermal-ManagementRegisters 1–2 (THRM1–THRM2) 2.1.4.2 Thermal-ManagementRegister 3 (THRM3) 2.1.4.3 Thermal-ManagementRegister 4 (THRM4) 2.1.5 L2 Cache Control Register (L2CR) 2.2 Operand Conventions 2.2.3 Floating-PointOperand and Execution Models—UISA 2.2.3.1 Denormalized Number Support 2.2.3.2 Non-IEEEMode (Nondenormalized Mode) 2.2.3.3 Time-Critical Floating-PointOperation 2.2.3.4 Floating-PointStorage Access Alignment 2.2.3.5 Optional Floating-PointGraphics Instructions fsel(.) fres(.) Page 2.3 Instruction Set Summary 2.3.1 Classes of Instructions 2.3.1.1 Definition of Boundedly Undefined 2.3.1.2 Defined Instruction Class fsqrt fsqrts 2.3.1.3 Illegal Instruction Class 2.3.1.4 Reserved Instruction Class 2.3.2 Addressing Modes 2.3.2.1 Memory Addressing 2.3.2.2 Memory Operands 2.3.2.3 Effective Address Calculation 2.3.2.4 Synchronization mfsrin) mtsrin 2.3.3 Instruction Set Overview 2.3.4 PowerPC UISA Instructions 2.3.4.1 Integer Instructions addi subf cmpi cmp cmpli andi andis 2.3.4.2 Floating-PointInstructions fmul fmadd fmsub fnmadd fnmsub Page mtfsf 2.3.4.3 Load-and-StoreInstructions Page Implementation Notes lha lhax lbzu Page eieio) Implementation Notes: Page lfsx lfsux lfdx lfdux Programming Note: Page stfsu stfdu 2.3.4.4 Branch and Flow-ControlInstructions bla bca Page 2.3.4.5 System Linkage Instruction—UISA 2.3.4.6 Processor Control Instructions—UISA mtcrf Page Page Page 2.3.4.7 Memory Synchronization Instructions—UISA 2.3.5 PowerPC VEA Instructions 2.3.5.1 Processor Control Instructions—VEA mftbu 2.3.5.2 Memory Synchronization Instructions—VEA 2.3.5.3 Memory Control Instructions—VEA Page 2.3.5.4 Optional External Control Instructions 2.3.6 PowerPC OEA Instructions 2.3.6.1 System Linkage Instructions—OEA 2.3.6.2 Processor Control Instructions—OEA 2.3.6.3 Memory Control Instructions—OEA tlbia 2.3.7 Recommended Simplified Mnemonics 3. Instruction-Cacheand Data-CacheOperation Page 3.1 Data-CacheOrganization 3.2 Instruction-CacheOrganization 3.3 Memory and Cache Coherency mtspr) 3.3.2 MEI Protocol Page 3.3.2.1 MEI Hardware Considerations 3.3.3 Coherency Precautions in Single-ProcessorSystems 3.3.4 Coherency Precautions in Multiprocessor Systems 3.3.5 PowerPC 750GX-InitiatedLoad/Store Operations 3.3.5.1 Performed Loads and Stores 3.3.5.2 Sequential Consistency of Memory Accesses 3.3.5.3 Atomic Memory References 3.4 Cache Control 3.4.1.1 Data-CacheFlash Invalidation 3.4.1.2 Enabling and Disabling the Data Cache dcbz) dcbf) 3.4.1.3 Locking the Data Cache 3.4.1.4 Instruction-CacheFlash Invalidation 3.4.1.5 Enabling and Disabling the Instruction Cache 3.4.1.6 Locking the Instruction Cache 3.4.2 Cache-ControlInstructions 3.4.2.2 Data Cache Block Zero (dcbz) 3.4.2.3 Data Cache Block Store (dcbst) 3.4.2.4 Data Cache Block Flush (dcbf) 3.4.2.5 Data Cache Block Invalidate (dcbi) 3.5 Cache Operations Page 3.5.2 Cache Flush Operations 3.6 L1 Caches and 60x Bus Transactions 3.6.1 Read Operations and the MEI Protocol 3.6.2 Bus Operations Caused by Cache-ControlInstructions 3.6.3 Snooping 3.6.4 Snoop Response to 60x Bus Transactions Page 3.6.5 Transfer Attributes Page 3.7 MEI State Transactions Page Page Page 4. Exceptions 4.1 PowerPC 750GX Microprocessor Exceptions 4.2 Exception Recognition and Priorities Page Page 4.3 Exception Processing 4.3.2 Machine Status Save/Restore Register 1 (SRR1) 4.3.3 Machine State Register (MSR) Page 4.3.4 Enabling and Disabling Exceptions 4.3.5 Steps for Exception Processing 4.3.6 Setting MSR[RI] 4.3.7 Returning from an Exception Handler 4.4 Process Switching 4.5 Exception Definitions 4.5.1 System Reset Exception (0x00100) 4.5.1.1 Soft Reset 4.5.1.2 Hard Reset Page Page 4.5.2 Machine-CheckException (0x00200) 4.5.2.1 Machine-CheckException Enabled (MSR[ME] = 1) 4.5.2.2 Checkstop State (MSR[ME] = 0) 4.5.3 DSI Exception (0x00300) 4.5.4 ISI Exception (0x00400) 4.5.5 External Interrupt Exception (0x00500) 4.5.6 Alignment Exception (0x00600) stmw 4.5.7 Program Exception (0x00700) 4.5.8 Floating-PointUnavailable Exception (0x00800) 4.5.9 Decrementer Exception (0x00900) 4.5.10 System Call Exception (0x00C00) 4.5.11 Trace Exception (0x00D00) 4.5.12 Floating-PointAssist Exception (0x00E00) 4.5.13 Performance-MonitorInterrupt (0x00F00) 4.5.14 Instruction Address Breakpoint Exception (0x01300) 4.5.15 System Management Interrupt (0x01400) 4.5.16 Thermal-ManagementInterrupt Exception (0x01700) 4.5.17 Data Address Breakpoint Exception 4.5.17.1 Data Address Breakpoint Register (DABR) 4.5.18 Soft Stops 4.5.19 Exception Latencies 4.5.20 Summary of Front-EndException Handling 4.5.21 Timer Facilities 4.5.22 External Access Instructions Page 5. Memory Management 5.1 MMU Overview Page 5.1.1 Memory Addressing 5.1.2 MMU Organization Page Page Page Page 5.1.3 Address-TranslationMechanisms 5.1.4 Memory-ProtectionFacilities 5.1.5 Page History Information 5.1.6 General Flow of MMU Address Translation 5.1.6.1 Real-AddressingMode and Block-Address-TranslationSelection 5.1.6.2 Page-Address-TranslationSelection Page 5.1.7 MMU Exceptions Summary Notes: 5.1.8 MMU Instructions and Register Summary 5.2 Real-AddressingMode 5.3 Block-AddressTranslation 5.4 Memory Segment Model 5.4.1.1 Referenced Bit lswx 5.4.1.2 Changed Bit 5.4.1.3 Scenarios for Referenced and Changed Bit Recording 5.4.2 Page Memory Protection 5.4.3 TLB Description 5.4.3.1 TLB Organization Page 5.4.3.2 TLB Invalidation 5.4.4 Page-Address-TranslationSummary Page 5.4.5 Page Table-SearchOperation Page Page 5.4.6 Page Table Updates 5.4.7 Segment Register Updates Page 6. Instruction Timing 6.1 Terminology and Conventions Page 6.2 Instruction Timing Overview Page Page Page 6.3 Timing Considerations 6.3.2 Instruction Fetch Timing 6.3.2.1 Cache Arbitration 6.3.2.2 Cache Hit Page Page Page Page 6.3.2.3 Cache Miss Page 6.3.2.4 L2 Cache Access Timing Considerations 6.3.2.5 Instruction Dispatch and Completion Considerations 6.3.2.6 Rename Register Operation 6.4 Execution-UnitTimings 6.4.1.1 Branch Folding 6.4.1.2 Branch Instructions and Completion 6.4.1.3 Branch Prediction and Resolution Page Page mulhw 6.4.2 Integer Unit Execution Timing 6.4.3 Floating-PointUnit Execution Timing fdivs fdiv mtfsb0 6.4.5 Load/Store Unit Execution Timing 6.4.6 Effect of Operand Placement on Performance 6.4.7 Integer Store Gathering 6.4.8 System Register Unit Execution Timing 6.5 Memory Performance Considerations 6.6 Instruction Scheduling Guidelines 6.6.1 Branch, Dispatch, and Completion-UnitResource Requirements 6.6.1.1 Branch-ResolutionResource Requirements 6.6.1.2 Dispatch-UnitResource Requirements 6.6.1.3 Completion-UnitResource Requirements 6.7 Instruction Latency Summary Page Page Page Page Page Page Page Page Page Page 7. Signal Descriptions 7.1 Signal Configuration 7.2 Signal Descriptions 7.2.1.2 Bus Grant (BG)—Input 7.2.1.3 Address Bus Busy (ABB) 7.2.2 Address Transfer Start Signals 7.2.2.1 Transfer Start (TS) 7.2.3 Address Transfer Signals 7.2.3.1 Address Bus (A[0–31]) 7.2.3.2 Address-BusParity (AP[0–3]) 7.2.4 Address Transfer Attribute Signals 7.2.4.1 Transfer Type (TT[0–4]) Page 7.2.4.2 Transfer Size (TSIZ[0–2])—Output 7.2.4.3 Transfer Burst (TBST) 7.2.4.4 Cache Inhibit (CI)—Output 7.2.4.5 Write-Through (WT)—Output 7.2.4.6 Global (GBL) 7.2.5 Address Transfer Termination Signals 7.2.5.1 Address Acknowledge (AACK)—Input 7.2.5.2 Address Retry (ARTRY) 7.2.6 Data-BusArbitration Signals 7.2.6.1 Data-BusGrant (DBG)—Input 7.2.6.2 Data-Bus Write-Only(DBWO) 7.2.6.3 Data Bus Busy (DBB) 7.2.7 Data-TransferSignals 7.2.7.1 Data Bus (DH[0–31], DL[0–31]) 7.2.7.2 Data-BusParity (DP[0–7]) 7.2.7.3 Data Bus Disable (DBDIS)—Input 7.2.8 Data-TransferTermination Signals 7.2.8.1 Transfer Acknowledge (TA)—Input Warning 7.2.8.2 Data Retry (DRTRY)—Input 7.2.8.3 Transfer Error Acknowledge (TEA)—Input 7.2.9 System Status Signals 7.2.9.1 Interrupt (INT)— Input 7.2.9.2 System Management Interrupt (SMI)—Input 7.2.9.3 Machine-CheckInterrupt (MCP)—Input 7.2.9.4 Checkstop Input (CKSTP_IN)—Input 7.2.9.5 Checkstop Output (CKSTP_OUT)—Output 7.2.10 Reset Signals 7.2.10.1 Hard Reset (HRESET)—Input 7.2.10.2 Soft Reset (SRESET)—Input 7.2.11 Processor Status Signals 7.2.11.1 Quiescent Request (QREQ)—Output 7.2.11.2 Quiescent Acknowledge (QACK)—Input 7.2.11.3 Reservation (RSRV)—Output 7.2.11.4 Time Base Enable (TBEN)—Input 7.2.11.5 TLB Invalidate Synchronize (TLBISYNC)—Input 7.2.12 Processor Mode Selection Signals 7.2.13 I/O Voltage Select Signals 7.2.14 Test Interface Signals 7.2.14.1 IEEE 1149.1a-1993Interface Description 7.2.14.2 LSSD_MODE 7.2.14.3 L1_TSTCLK 7.2.14.4 L2_TSTCLK 7.2.14.5 BVSEL 7.2.15 Clock Signals 7.2.15.1 System Clock (SYSCLK)—Input 7.2.15.2 Clock Out (CLK_OUT)—Output 7.2.15.3 PLL Configuration (PLL_CFG[0:4])—Input 7.2.15.4 PLL Range (PLL_RNG[0:1])—Input 7.2.16 Power and Ground Signals 8. Bus Interface Operation 8.1 Bus Interface Overview 8.1.1 Operation of the Instruction and Data L1 Caches 8.1.2 Operation of the Bus Interface 8.1.3 Bus Signal Clocking System Implementation Note: 8.1.4 Optional 32-BitData Bus Mode 8.1.5 Direct-StoreAccesses 8.2 Memory-AccessProtocol 8.2.1 Arbitration Signals 8.2.2 Miss-under-Miss 8.2.2.1 Miss-under-Missand System Performance Page Page 8.3 Address-BusTenure Page 8.3.2 Address Transfer Page 8.3.2.1 Address-BusParity 8.3.2.2 Address Transfer Attribute Signals 8.3.2.3 Burst Ordering During Data Transfers 8.3.2.4 Effect of Alignment in Data Transfers Page Page Page 8.3.2.5 Alignment of External Control Instructions 8.3.3 Address Transfer Termination 8.4 Data-BusTenure 8.4.1.1 Using the DBB Signal 8.4.2 Data-Bus Write-Only 8.4.3 Data Transfer 8.4.4 Data-TransferTermination 8.4.4.1 Normal Single-BeatTermination Page Page 8.4.4.2 Data-TransferTermination Due to a Bus Error 8.4.5 Memory Coherency—MEIProtocol 8.5 Timing Examples Page Page Page Page Page Page 8.6 Optional Bus Configuration Page 8.6.2 No-DRTRYMode 8.7 Processor State Signals 8.8 IEEE 1149.1a-1993Compliant Interface 8.9 Using Data-Bus Write-Only Page Page 9. L2 Cache 9.1 L2 Cache Overview 9.2 L2 Cache Operation Page Page Page Page dcbst) dcbi) sync) 9.3 L2 Cache Control Register (L2CR) 9.4 L2 Cache Initialization 9.5 L2 Cache Global Invalidation 9.6 L2 Cache Used as On-ChipMemory 9.6.1.1 Loading the Locked L2 Cache 9.6.1.2 Locked Cache Operation 9.7 Data-Onlyand Instruction-OnlyModes 9.8 L2 Cache Test Features and Methods 9.9 L2 Cache Timing Page 10. Power and Thermal Management 10.1 Dynamic Power Management 10.2 Programmable Power Modes Page 10.2.1 Power Management Modes 10.2.1.1 Full On Mode 10.2.1.2 Doze Mode 10.2.1.3 Nap Mode Page 10.2.1.4 Sleep Mode 10.2.1.5 Dynamic Power Reduction 10.3 750GX Dual PLL Feature 10.3.2 Configuration Restriction on Frequency Transitions 10.3.3 Dual PLL Implementation 10.4 Thermal Assist Unit 10.4.2 Thermal Assist Unit Operation 10.4.2.1 TAU Single-ThresholdMode 10.4.2.2 TAU Dual-ThresholdMode 10.4.2.3 750GX Junction Temperature Determination 10.5 Instruction-CacheThrottling Page 11. Performance Monitor and System Related Features 11.1 Performance-MonitorInterrupt 11.2 Special-PurposeRegisters Used by Performance Monitor 11.2.1 Performance-MonitorRegisters 11.2.1.1 Monitor Mode Control Register 0 (MMCR0) 11.2.1.2 User Monitor Mode Control Register 0 (UMMCR0) 11.2.1.3 Monitor Mode Control Register 1 (MMCR1) 11.2.1.4 User Monitor Mode Control Register 1 (UMMCR1) Page Page 11.2.1.6 User Performance-MonitorCounter Registers (UPMC1–UPMC4) 11.3 Event Counting 11.4 Event Selection 11.5 Notes 11.6 Debug Support 11.7 JTAG/COP Functions Page 11.8 Resets 11.8.3 Reset Sequence 11.9 Checkstops 11.9.3 Open-Collector-DriverStates during Checkstop 11.9.4 Vacancy Slot Application 11.10 750GX Parity 11.10.1 Parity Control and Status 11.10.2 Enabling Parity Error Detection 11.10.3 Parity Errors Acronyms and Abbreviations Page Page Page Index Page H, I, J, K Page Page Page U, V, W Page Revision Log