Intel MultiProcessor manual PIC Mode

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Hardware Specification

The first two interrupt modes, PIC Mode and Virtual Wire Mode, provide PC/AT-compatibility. At least one of these modes must be implemented in systems that comply with the MP specification. In these modes, full DOS compatibility with the uniprocessor PC/AT is provided by using the APICs in conjunction with standard 8259A-equivalent programmable interrupt controllers (PICs).

The third mode, Symmetric I/O Mode, must be implemented in addition to either PIC Mode or Virtual Wire Mode. An MP operating system is booted under either one of the two PC/AT- compatible modes. Later the operating system switches to Symmetric I/O Mode as it enters multiprocessor mode.

The interrupt modes are implemented by a combination of hardware and software. The hardware and programming specifications for each of these modes are further defined in the following subsections. BIOS programmers should refer to Appendix A, which includes information about programming the APIC for Virtual Wire Mode. Operating system programmers should refer to Appendix B, which provides more information about initializing the APIC for Symmetric I/O Mode.

3.6.2.1PIC Mode

PIC Mode is software compatible with the PC/AT because it actually employs the same hardware interrupt configuration. As Figure 3-2 illustrates, the hardware for PIC Mode bypasses the APIC components by using an interrupt mode configuration register (IMCR). This register controls whether the interrupt signals that reach the BSP come from the master PIC or from the local APIC. Before entering Symmetric I/O Mode, either the BIOS or the operating system must switch out of PIC Mode by changing the IMCR.

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Contents MultiProcessor Specification Copyright 1993-1997. Intel Corporation, All Rights Reserved Revision Revision History Date Revision HistoryPage Table of Contents MP Configuration Table Default ConfigurationsContents Appendix a System Bios Programming Guidelines Appendix B Operating System Programming GuidelinesAppendix E Errata Glossary Tables FiguresExamples Page Conceptual Overview GoalsFeatures of the Specification MultiProcessor SpecificationScope Introduction Target AudienceOrganization of This Document Document OrganizationFor More Information Conventions Used in This DocumentSystem Overview System Processors Hardware OverviewSystem Overview Advanced Programmable Interrupt Controller4 I/O Expansion Bus System MemoryOperating System Overview Bios OverviewPage System Memory Configuration Hardware SpecificationSystem Memory Address Map System Memory Cacheability and ShareabilityMemory Cacheability Map Hardware SpecificationLocking External Cache SubsystemPosted Memory Write Multiprocessor Interrupt ControlApic Architecture Apic Versions Interrupt ModesPIC Mode PIC Mode Virtual Wire Mode via Local Apic Virtual Wire ModeVirtual Wire Mode via I/O Apic Symmetric I/O Mode Symmetric I/O ModeAssignment of System Interrupts to the Apic Local Unit Floating Point Exception InterruptApic Memory Mapping Apic Identification Apic Interval TimersSystem-wide Reset Reset SupportProcessor-specific Init System-wide InitSystem Initial State Support for Fault-resilient BootingMP Configuration Table MultiProcessor Specification MP Configuration Table MP Floating Pointer StructureOffset Length Field Bytesbits in bits Description Information Bytes MP FeatureOffset Length Field Bytesbits Bits Description Information ByteMP Configuration Table Header MP Configuration Table HeaderBase MP Configuration Table Entries MP Configuration Table Header FieldsOffset Length Field Bytes Bits Description Apic Base MP Configuration Table Entry TypesProcessor Entries Length Entry Description Entry Type Code Bytes CommentsProcessor Entry Fields Bit Name Description Comments Feature Flags from Cpuid InstructionIntel486 and Pentium Processor Signatures Family Model Stepping a DescriptionString Bus EntriesBUS ID BUS TypeBus Type String Description Bus Type String ValuesI/O Apic Entry Fields 3 I/O Apic Entries4 I/O Interrupt Assignment Entries Apic EntryI/O Interrupt Entry 10. I/O Interrupt Entry Fields Local Interrupt Assignment Entries 11. Interrupt Type ValuesInterrupt Type Description Comments LINTIN# 12. Local Interrupt Entry FieldsDestination Local Apic ID Destination Local ApicExtended MP Configuration Table Entries System Address Space Mapping Entries 14. System Address Space Mapping Entry Fields 10. Example System with Multiple Bus Types and Bridge Types Bus Hierarchy Descriptor Entry Compatibility Bus Address Space Modifier Entry 12. Compatibility Bus Address Space Modifier Entry 16. Compatibility Bus Address Space Modifier Entry Fields Default Configurations Config Code CPUs Type Variant Schematic Discrete Apic ConfigurationsDefault Configurations Default Number BusDefault Configurations Default Configuration for Discrete ApicIntegrated Apic Configurations Default Configuration for Integrated Apic First I/O Default Configuration Interrupt AssignmentsConfig INTINx Comments Assignment of I/O Interrupts to the Apic I/O UnitLevel-triggered Interrupt Support All Local APICs Config LINTINx CommentsAssignment of System Interrupts to the Apic Local Unit Eisa and IRQ13MultiProcessor Specification Bios Post Initialization System Bios Programming GuidelinesControlling the Application Processors Programming the Apic for Virtual Wire ModeSystem Bios Programming Guidelines Example A-1. Programming Local Apic for Virtual Wire ModeNMI Constructing the MP Configuration TableSystem Bios Programming Guidelines Page Operating System Programming Guidelines Operating System Boot-upInterrupt Mode Initialization and Handling Operating System Booting and Self-configurationOperating System Programming Guidelines Application Processor StartupUsing Init IPI AP Shutdown Handling Using Startup IPIHandling TLB Invalidation Other IPI ApplicationsSpurious Apic Interrupts Handling Cache FlushSupporting Unequal Processors Page System Compliance Checklist Page Variable Interrupt Routing Interrupt Routing with Multiple APICsFixed Interrupt Routing INTD# Bus Entries in Systems with More Than One PCI BusI/O Interrupt Assignment Entries for PCI Devices Multiple I/O Apic Multiple PCI Bus SystemsPage Errata 126 System Address Space Entry System Address Space Mapping EntriesAddress Base 14. System Address Space Mapping Entry FieldsEntry Length Address TypeSpace records must also be provided Bus Hierarchy Descriptor EntryParent BUS BUS InformationsdGlossary Glossary-2 Order Number