In order to compete with

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

's Advanced Programmable Interrupt Controller (APIC), which had enabled the first Intel 486-based

multiprocessor Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There ar ...

systems, in early 1995

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...

and

Cyrix Cyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas, as a specialist supplier of floating point units for 286 and 386 microprocessors. The company was founded by Tom Brightman and Jerry Rogers. In 19 ...

proposed as somewhat similar-in-purpose OpenPIC architecture supporting up to 32 processors. The OpenPIC architecture had at least declarative support from IBM and

Compaq Compaq Computer Corporation (sometimes abbreviated to CQ prior to a 2007 rebranding) was an American information technology company founded in 1982 that developed, sold, and supported computers and related products and services. Compaq produced ...

around 1995. No x86 motherboard was released with OpenPIC however. After the OpenPIC's failure in the x86 market, AMD licensed the

Intel APIC Architecture In computing, Intel's Advanced Programmable Interrupt Controller (APIC) is a family of interrupt controllers. As its name suggests, the APIC is more advanced than Intel's 8259 Programmable Interrupt Controller (PIC), particularly enabling the co ...

for its

AMD Athlon Athlon is the brand name applied to a series of x86-compatible microprocessors designed and manufactured by Advanced Micro Devices (AMD). The original Athlon (now called Athlon Classic) was the first seventh-generation x86 processor and the fi ...

and later processors. IBM however developed their Multiprocessor Interrupt Controller (MPIC) based on the OpenPIC register specification. In the reference IBM design, the processors share the MPIC over a DCR bus, with their access to the bus controlled by a DCR Arbiter. MPIC supports up to four processors and up to 128 interrupt sources.IB
Multiprocessor Interrupt Controller. Data Book
Through various implementations, the MPIC was included in

PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple Inc., App ...

reference designs and some retail computers. IBM used a MPIC based on OpenPIC 1.0 in their RS/6000 F50 and one based on OpenPIC 1.2 in their RS/6000 S70. Both of these systems also used a dual

8259 The Intel 8259 is a Programmable Interrupt Controller (PIC) designed for the Intel 8085 and Intel 8086 microprocessors. The initial part was 8259, a later A suffix version was upward compatible and usable with the 8086 or 8088 processor. The 8 ...

on their PCI-ISA bridges. An IBM MPIC was also used in the RS/6000 7046 Model B50. The

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

Hydra Mac I/O (MIO) chip (from the 1990s

classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Macintosh family of personal computers by Apple Computer from 1984 to 2001, starting with System 1 and ending with Mac OS 9. The ...

era) implemented a MPIC alongside a

SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, electrical, optical and logical interface ...

controller, ADB controller, GeoPort controller, and timers. The Apple implementation of "Open PIC" (as the Apple documentation of this era spells it) in their first MIO chip for the

Common Hardware Reference Platform __NOTOC__ Common Hardware Reference Platform (CHRP) is a standard system architecture for PowerPC-based computer systems published jointly by IBM and Apple in 1995. Like its predecessor PReP, it was conceptualized as a design to allow various op ...

was based on version 1.2 of the register specification and supported up to two processors and up to 20 interrupt sources. A MPIC was also incorporated in the newer K2 I/O controller used in the Power Mac G5s. Freescale also uses a MPIC ("compatible with the Open PIC") on all its PowerQUICC and

QorIQ QorIQ is a brand of ARM-based and Power ISA-based communications microprocessors from NXP Semiconductors (formerly Freescale). It is the evolutionary step from the PowerQUICC platform, and initial products were built around one or more e500mc ...

processors. The Linux Kernel-based Virtual Machine (KVM) supports a virtualized MPIC with up to 256 interrupts, based on the Freescale variants.

References

{{Reflist, 30em

External links

AppleMPIC open source code
Motherboard Interrupts AMD platforms Macintosh platform IBM computer hardware Freescale Semiconductor

See also

References

External links