~!~~~~E L~~E~~~s~ I~I! ~ J | Intel 80386 guide

80386

When operating in Protected Mode, the segment base, limit, and other attributes within the segment cache registers are defined as shown in Figure 4-12. In Protected Mode, each of these fields are defined

according to the contents of the segment descriptor indexed by the selector value loaded into the seg- ment register.

SEGMENT		DESCRIPTOR CACHE REGISTER CONTENTS
	32 -	BIT BASE	32 - BIT LIMIT	OTHER ATTRIBUTES
	(UPDATED DURING		(UPDATED DURING	(UPDATED DURING
	SELECTOR LOAD INTO		SELECTOR LOAD INTO	SELECTOR LOAD INTO
	SEGMENT REGISTER)		SEGMENT REGISTER)	SEGMENT REGISTER)
CONFORMING PRIVILEGE -----------------------					. ,
STACK SIZE -----------------------					,
EXECUTABLE -----------------------					,
WRITEABLE		--------------------		~
READABLE --------------------				,
EXPANSION DIRECTION				1
GRANULARITY
ACCESSED				1
~:!~~~~E_L~~E~~~s~___________ :I~I!______ ~J1____
CS	BASE PER SEG DESCR		LIMIT PER SEG DESCR	P d d d d d N Y -		d
SS	BASE PER SEG DESCR		LIMIT PER SEG DESCR	P d d d d r w N d		-
OS	BASE PER SEG DESCR		LIMIT PER SEG DESCR	p d d d d d d N - -
ES	BASE PER SEG DESCR		LIMIT PER SEG DESCR	p d d d d d d N -		-
FS	BASE PER SEG DESCR		LIMIT PER SEG DESCR	P d d d d d d N -		-
GS	BASE PER SEG DESCR		LIMIT PER SEG DESCR	p d d d d d d N - -

231630-61

Key: Y = fixed yes N = fixed no

d = per segment descriptor

p= per segment descriptor; descriptor must indicate "present" to avoid exception 11 (exception 12 in case of SS)

r= per segment descriptor, but descriptor must indicate "readable" to avoid exception 13 (special case for SS)

w= per segment descriptor, but descriptor must indicate "writable" to avoid exception 13 (special case for SS)

-= does not apply to that segment cache register

Figure 4-12. Segment Descriptor Caches for Protected Mode (Loaded per Descriptor)

43

Image 104

Intel 80386 manual ~!~~~~E L~~E~~~s~ I~I! ~ J

Contents

Page Inter Intel Corporation Table of Contents Chapter Architectural Compatibility Chapter Highlights Page 32-bit Architecture High-performance Implementation Highlights Extended Debugging Support Configurable ProtectionVirtual Memory Support Object Code Compatibility Summary Application Architecture Page Flags and Instruction Pointer RegistersGeneral Registers Numeric Coprocessor Registers Memory and logical Addressing Segment and Descriptor Registers Logical Address Translation Addressing Modes Data Types and Instructions Principal Data Types Stack Instructions Numeric Coprocessor Data TypesOther Instructions ~.,...I-------.-1 Byte String LII Miscellaneous Instructions Chapter System Architecture Page System Registers Multitasking Task Switching Task State Segment Addressing Address Translation Overview Segments Address Translation Overview Principal Descriptor Fields ~~~~~.II~~~ Pages Virtual Memory Linear to Physical Address Translation I I I Protection Privilege USing Privilege Levels Privileged Instructions Segment Protection Protection Interrupts and Exceptions 10. Gates as Protected Entry Points Interrupt Descriptor Table Debug Eceptions and Registers System Architecture Page Architectural Compatibility Page 80286 Compatibility Real and Virtual 86 Modes Architectural Compatibility Trapping Virtual 861\11ode System Calls Page Chapter Hardware Implementation Page Chapter Hardware Implementation Hardware Implementation Clock Data and Address Buses Bus Cycle Definition Bus Cycle Control Non-pipelined Bus Cycle Timing Bus Cycles with Pipelined Addresses Coprocessor Control Dynamic Bus SizingProcessor Status and Control Mixed 16- and 32-bit Accesses Chapter Data Sheet Page 80386 Update Notice Table of Contents Descriptor Tables Introduction Interrupt Descriptor TableSegment Descriptor Cache Privilege Validation Functional Data Package Thermal Specification 3.4Initiating and Maintaining Pipelined Address Pipelined Address with Dynamic Data Bus Sizing Base Architecture Introduction Register Overview Register Descriptions General Purpose RegistersInstruction Pointer Flags Register TSS Other Segment Physical Base Address Segment Limit Segment RegistersSegment Registers Descriptor Registers Loaded Automatically Segment Descriptor Registers Control RegistersFlects the current state of the ET bit MSW TS Task Switched, bit Fault Linear Address Register CR2System Address Registers Directory Base Register CR3 Compatibility Register AccessibilityDebug and Test Registers Instruction Set Overview IoplGdtr Idtr 2 80386 Instructions 2dLogical Instructions2a Data Transfer 2b Arithmetic Instructions 2e Bit Manipulation Instructions 2f. Program Control Instructions2g High Level Language Instructions 2h Protection Model 3 32-Bit Memory Addressing Modes Addressing Modes OverviewRegister and Immediate Modes Addressing Mode Calculations Differences Between 16 and 32 Bit Addresses Displacement Data TypesBase Register BX,BP Index Register SI,DI Scale Factor None LilliililillIl Sign ED rrrrrrrrl Address Spaces Memory OrganizationIntroduction I/O Space Segment Register Usage Interrupts Interrupts and Ecep~ionsInterrupt Processing Maskable Interrupt Non-Maskable Interrupt Software Interrupts Interrupt and Exception Priorities NMI 2.INTR Instruction Restart Reset and InitializationDouble Fault TLB Testing TestabilitySelf-Test Debugging Support Debug Registers Breakpoint InstructionSingle-Step Trap DR1 DR2DR3 DR4 Encoding Causing Breakpoint Usage Real Mode Architecture Real Mode Introduction Debug Status Register DR6 SET/RESET/COMPLEMENT Memory AddressingXchg ADD, OR, ADC, SBB Shutdown and Halt Reserved LocationsIntierrupts Protected Mode Addressing Addressing Mechanism Segmentation Introduction TerminologyDescriptor Tables Descriptor Tables Introduction Descriptors ByteAddress Segment Base 15 Segment Limit 15 Dptm typ , data gm,nt System Descriptor Formats Selector Offset 15Word Offset 31 Differences Between 386 and 286 Descriptors Segment Base 15Selector Fields Segment Descriptor Cache Nil R~L ~~~~~~~EL~~E~ ~A~~ ~I~I! ttl ~!~~~~E L~~E~~~s~ I~I! ~ J ~~?~~~~EL~~E~B~~E ~I~I~ tJ1 Privilege Levels Protection ConceptsRules of Privilege Privilege Level Transfers GOT/LOT CallRET,IRET CALL, JMP 80386 Task Switching Call Ga~es Initialization and Transition to Protected Mode Infef Tools for Building Protected PagingSystems Paging Concepts Paging Organization MechanismDescriptor Base Register Directory Level Protection R/W, U/S Bits Frame Address 31 ReservedTables DIRECTORY/TABLE Entries Translation Lookaside Buffer Paging Operation Paging In Virtual Mode Access TypeVirtual 8086 Environment Executing 8086 Programs Protection and 1/0 Permission Bitmap 24. Virtual 8086 Environment Memory Management Interrupt Handling Entering and Leaving Virtual Task Switches TO/FROM Virtual 8086 Mode ·25.Virtual 8086 Environment Interrupt and Call Handling For state saving i.e. push all registers in prolog, pop Introduction Clock CLK2 Data Bus do through Address Bus BEO# through BE3#, A2 through A31 Bus Cycle Definition Signals W/R#, D/C#, MIIO#, LOCK# Bus Control Signals Introduction Bus Arbitration Signals Coprocessor Interface Signals Interrupt Signals Signal Summary Memory and 1/0 Spaces BEO# Memory and 110 Organization Dynamic Data Bus Sizing Interfacing with 32- and 16-Bit Memories Cycles 1 and 1a Operand Alignment BEO# BHE# BLE# AD Li,\~~ P1 1.p2 .p1 1.p2 .p1 1.p2 .p1 1.p2 .p1 1.p2 .p1 1.p2 .p1 Address Pipelining ·9.Fastest Read Cycles with Pipelined Address Timing FOUR-BANK Interleaved Memory Address signal A2 selects bank Bit datapath to each bankTWO-BANK Interleaved Memory Read and Write Cycles Introduction NON-PIPELINED Address Xxxxx IxxxxXxxi Xxxix Ixxx 13 80386 Bus States not usIng pipelined address 3.3 NON·PIPELINED Address with Dynamic Data BUS Sizing ·14Asserting BS16# zero wait states, non·pipelinedaddress Xixxxxx Valid Xixxxx ,XXXXY~~~~ DOO¥ BSI6# XXX XXx XXX X .. IXXXXwOO~ J, XXX XXX1/ \ B516# ~~..tJ.~~~~~~~ BS16 # 44~~~...l-.lI...l Ready # 44~~.lI...l/l Bus Sizing with Pipelined Address Acknowledge ~ ,T1-T~-T2PJ ,T1PT2PJ Idle non-pipelined pipelinedPipelined IO#, D/c# Ffi 20 Complete Bus States including pipelined address Xxxxy ~j XDONTCAR~X~ x~ ~X~~lKX~ /..XXXX Xxxxx IXXXXIXXXXI.. /..DXXXIXXX ~ XxxxiyXxixxy ~ /..XIXXY ~ -XXIXXY Interrupt Acknowledge Inta Cycles ~--cp--- ----- ----- ----- ----- ~ Halt Indication Cycle 23.Halt Indication Cycle Shutdown Indication Cycle 24. Shutdown Indication Cycle Reset During Hold Acknowledge Bus Activity During and Following ResetOther Functional Descriptions Entering and Exiting Hold Acknowledge 26. Requesting Hold from Active Bus NA # negated SELF-TEST Signature Component and Revision Identifiers Component Revision Component Revision Stepping Identifier Name Software Testing for Coprocessor Presence CMD1 Mechanical Data Introduction PIN Assignment 000 0 0 0 000 0 0 Vee Vss Package Dimensions and Mounting 1654189~1 Package Thermal Specification Measure PGA Case Temperature Infef80386 Ill Power and Grounding Electrical Data D.C. Specifications Maximum Ratings 102 A.C. Specifications1 A.C. Spec Definitions Unit Min Max Operating Frequency MHz Half of CLK2 2 A.C. Specification Tables·4 -16 A.C. Characteristics Symbol Parameter 80386-16 80386-16 Min Unit Max 16 A.C. Characteristics Symbol ParameterSymbol Parameter Min 3 A.C. Test Loads 4 A.C. Timing Waveforms 80386 ~QW~OOg OOOIP@OOIMl~iiO@OO 106 MAX Itm PI~ Instruction SET 80386 Instruction Encoding 8o386Instructlon Set CIock Count Summary 111 ·1 Instruction Set Clock Count Summary 112 80386 Instructlon Set CIockCount S ummary Contlnued RIm ·1 80386 Instruction Set Clock Count Summary Doubleword Instruction Set Clock Count Summary 115 Instruction Set Clock Count Summarycontlnued BIT Manipulation Instruction Set Clock Count Summar +ml 7+ml 80386 Ins ruefIon SetCIoek CountSummary ConrInued Protected 119 120 80386 Instructlon Set CIockCountSummaay Contmued Interrupt Instructions O3861nstructlon Set CIockCount Summary Contlnued Bound Infef80386 80386 nstructlon Set CIockCount Summary Contlnued Ns ruetIon StCIe oekCount 5 ummary Contlnued Madear Overview ~~~\ 2 32-Bit Extensions of the Instruction Set Encoding of Instruction FieldsField Bits Encoding of Address Mode Osbx OSBX+d1611010 EOI OS EAX Scale Factor Encoding of Operation Direction NAENB/AE NE/NZ Domestic Sales Offices California United States