Lii | Intel 80386 specification

APPLICATION ARCHITECTURE

transfered to any point in a segment. (The selector part of the far pointer replaces the value in the CS register while the offset part replaces the value in EIP) A full set of condi- tional Jump instructions, which branch based on the value of a status flag, is also available; these instructions can also transfer to locations up to 232 bytes away.

Procedures and functions (subroutines) can be invoked with the Call instruction and a called routine can return with the Return instruction. As with Jumps, Calls within a code segment have near pointer operands which specify a new value for the Instruction Pointer, while Calls to a different code segment have far pointer operands that change the CS register in addition to EIP. Call instructions push the address of the following instruction

onto the stack and then load the Instruction Pointer (and the CS register, if the transfer is to a different segment). The Return instruction pops the saved value(s) from the stack into Erp, and CS, if applicable. Calls can be indefinitely nested and recursive, subject only to the size of the stack.

For controlling loops, the 80386 provides the Loop and conditional Loop instructions in addition to conditional Jumps. The loop instructions use the ECX register as a repeti- tion counter; they decrement ECX and termi- nate the loop when the register's value becomes zero. The conditional Loop instructions termi- nate a loop prematurely when a flag takes a specified value. While the Loop instructions are designed for "bottom of loop" testing, adding a Jump If ECX Zero instruction

							IRELATIVE
							ADDRESSES
		..."'f-----		INCREASING SIGNIFICANCE
79	71	I				3	0
(G::::J		I				I I I IPACKED DECIMAL
Q ...'S - IG - N			--------	MAGNITUDE -----------			'
				31	23		0
				11... --		________1SHORT REAL
				l'•II		MAGNITUDE----....	J
						BIASED EXPONENT
						SIGN
		63	51				0
		LJIIL-_-LI____________---JILONG REAL
			II	MAGNITUDE
		~t		BIASED EXPONENT
				SIGN
79		62					0
I..&..1___--11...11_________________---11 TEMPORARY REAL
tL.1_--	,-_	---llL.I-------		MAGNITUDE
l	t____BIASED EXPONENT
L - . -----		SIGN

Figure 2-8. Numeric Coprocessor Data Type Storage Examples

2-9

Image 22

Intel 80386 manual Lii

Contents

Page Inter Intel Corporation Table of Contents Chapter Architectural Compatibility Chapter Highlights Page 32-bit Architecture High-performance Implementation Highlights Virtual Memory Support Configurable ProtectionExtended Debugging Support Object Code Compatibility Summary Application Architecture Page General Registers RegistersFlags and Instruction Pointer Numeric Coprocessor Registers Memory and logical Addressing Segment and Descriptor Registers Logical Address Translation Addressing Modes Data Types and Instructions Principal Data Types Other Instructions Numeric Coprocessor Data TypesStack 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 Processor Status and Control Dynamic Bus SizingCoprocessor Control Mixed 16- and 32-bit Accesses Chapter Data Sheet Page 80386 Update Notice Table of Contents Segment Descriptor Cache Descriptor Tables IntroductionInterrupt Descriptor Table Privilege Validation Functional Data Initiating and Maintaining Pipelined Address Package Thermal Specification3.4 Pipelined Address with Dynamic Data Bus Sizing Base Architecture Introduction Register Overview Instruction Pointer Register DescriptionsGeneral Purpose Registers Flags Register TSS Segment Registers Descriptor Registers Loaded Automatically Segment RegistersOther Segment Physical Base Address Segment Limit Flects the current state of the ET bit Segment Descriptor RegistersControl Registers MSW System Address Registers TS Task Switched, bitFault Linear Address Register CR2 Directory Base Register CR3 Debug and Test Registers Register AccessibilityCompatibility Gdtr Instruction Set OverviewIopl Idtr 2a Data Transfer 2 80386 Instructions2dLogical Instructions 2b Arithmetic Instructions 2g High Level Language Instructions 2e Bit Manipulation Instructions2f. Program Control Instructions 2h Protection Model Register and Immediate Modes Addressing Modes Overview3 32-Bit Memory Addressing Modes Addressing Mode Calculations Differences Between 16 and 32 Bit Addresses Base Register BX,BP Index Register SI,DI Scale Factor DisplacementData Types None LilliililillIl Sign ED rrrrrrrrl Introduction Memory OrganizationAddress Spaces I/O Space Segment Register Usage Interrupt Processing InterruptsInterrupts and Ecep~ions Maskable Interrupt Non-Maskable Interrupt Software Interrupts Interrupt and Exception Priorities NMI 2.INTR Double Fault Reset and InitializationInstruction Restart Self-Test TLB TestingTestability Debugging Support Single-Step Trap Breakpoint InstructionDebug Registers DR3 DR1DR2 DR4 Encoding Causing Breakpoint Usage Real Mode Architecture Real Mode Introduction Debug Status Register DR6 Xchg SET/RESET/COMPLEMENTMemory Addressing ADD, OR, ADC, SBB Intierrupts Reserved LocationsShutdown and Halt Protected Mode Addressing Addressing Mechanism Descriptor Tables Segmentation IntroductionTerminology Descriptor Tables Introduction Address DescriptorsByte Segment Base 15 Segment Limit 15 Dptm typ , data gm,nt System Descriptor Formats Word SelectorOffset 15 Offset 31 Selector Fields Differences Between 386 and 286 DescriptorsSegment Base 15 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 Rules of Privilege Protection ConceptsPrivilege Levels Privilege Level Transfers RET,IRET GOT/LOTCall CALL, JMP 80386 Task Switching Call Ga~es Initialization and Transition to Protected Mode Infef Systems Tools for Building ProtectedPaging Paging Concepts Descriptor Base Register Paging OrganizationMechanism Directory Tables Level Protection R/W, U/S BitsFrame Address 31 Reserved DIRECTORY/TABLE Entries Translation Lookaside Buffer Paging Operation Virtual 8086 Environment Paging In Virtual ModeAccess Type 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 TWO-BANK Interleaved Memory Address signal A2 selects bank Bit datapath to each bankFOUR-BANK Interleaved Memory Read and Write Cycles Introduction Xxxi Xxxix NON-PIPELINED AddressXxxxx Ixxxx 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 ~~~~ DOO¥ Xixxxxx ValidXixxxx ,XXXXY 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 Pipelined ~ ,T1-T~-T2PJ ,T1PT2PJ Idle non-pipelined pipelinedAcknowledge IO#, D/c# Ffi 20 Complete Bus States including pipelined address Xxixxy ~ /..XIXXY Xxxxy ~j XDONTCAR~X~ x~ ~X~~lKX~ /..XXXXXxxxx IXXXXIXXXXI.. /..DXXXIXXX ~ Xxxxiy ~ -XXIXXY Interrupt Acknowledge Inta Cycles ~--cp--- ----- ----- ----- ----- ~ Halt Indication Cycle 23.Halt Indication Cycle Shutdown Indication Cycle 24. Shutdown Indication Cycle Other Functional Descriptions Reset During Hold AcknowledgeBus Activity During and Following Reset 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 1 A.C. Spec Definitions A.C. Specifications102 ·4 -16 A.C. Characteristics Symbol Parameter 80386-16 2 A.C. Specification TablesUnit Min Max Operating Frequency MHz Half of CLK2 Symbol Parameter Min 16 A.C. Characteristics Symbol Parameter80386-16 Min Unit Max 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 ~~~\ Field 2 32-Bit Extensions of the Instruction SetEncoding of Instruction Fields Bits Encoding of Address Mode 11010 OsbxOSBX+d16 EOI OS EAX Scale Factor NB/AE Encoding of Operation DirectionNAE NE/NZ Domestic Sales Offices California United States