PA-RISC - AbsoluteAstronomy.com

PA-RISC is an instruction set architecture (ISA) developed by Hewlett-Packard

Hewlett-Packard

Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

. As the name implies, it is a reduced instruction set computer

Reduced instruction set computer

Reduced instruction set computing, or RISC , is a CPU design strategy based on the insight that simplified instructions can provide higher performance if this simplicity enables much faster execution of each instruction. A computer based on this strategy is a reduced instruction set computer...

(RISC) architecture, where the PA stands for Precision Architecture. The design is also referred to as HP/PA for Hewlett Packard Precision Architecture.

The architecture was introduced on 26 February 1986 when the HP 3000 Series 930

HP 3000

The HP 3000 series is a family of minicomputers released by Hewlett-Packard in 1973. It was designed to be the first minicomputer delivered with a full featured operating system with time-sharing. The first models were withdrawn from the market until speed improvements could be made. It ultimately...

and HP 9000 Model 840

HP 9000

HP 9000 is the name for a line of workstation and server computer systems produced by the Hewlett-Packard Company . The native operating system for almost all HP 9000 systems is HP-UX, a derivative of Unix. The HP 9000 brand was introduced in 1984 to encompass several existing technical...

computers were launched featuring the first implementation, the TS1.

PA-RISC has been succeeded by the Itanium

Itanium

Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...

(originally IA-64) ISA jointly developed by HP and Intel

Intel Corporation

Intel Corporation is an American multinational semiconductor chip maker corporation headquartered in Santa Clara, California, United States and the world's largest semiconductor chip maker, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most...

. HP stopped selling PA-RISC-based HP 9000 systems at the end of 2008 but will support servers running PA-RISC chips until 2013.

History

In the late 1980s HP was building four series of computers, all based on CISC

Complex instruction set computer

A complex instruction set computer , is a computer where single instructions can execute several low-level operations and/or are capable of multi-step operations or addressing modes within single instructions...

CPUs. One line was the IBM PC compatible

IBM PC compatible

IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...

Intel i286 based Vectra Series started 1986. All others were non-Intel systems. One of them was the HP Series 300 of Motorola 68000

Motorola 68000

The Motorola 68000 is a 16/32-bit CISC microprocessor core designed and marketed by Freescale Semiconductor...

-based workstation

Workstation

A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...

s, another Series 200 line of technical workstations based on a custom silicon on sapphire

Silicon on sapphire

Silicon on sapphire is a hetero-epitaxial process for integrated circuit manufacturing that consists of a thin layer of silicon grown on a sapphire wafer. SOS is part of the Silicon on Insulator family of CMOS technologies...

(SOS) chip design, the SOS based 16-bit HP 3000

HP 3000

classic series and finally the HP 9000 Series 500 minicomputer

Minicomputer

A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...

s, based on their own (16 and 32-bit) FOCUS microprocessor. HP planned to use PA-RISC to move all of their non-PC compatible machines to a single RISC CPU family.

Precision Architecture was introduced in 1986. It had thirty-two 32-bit integer registers and sixteen 64-bit floating-point registers. The number of floating-point registers was doubled in the 1.1 version to 32 once it became apparent that 16 were inadequate and restricted performance. The architects included Allen Baum, Hans Jeans, Michael J. Mahon, Ruby Bei-Loh Lee, Russel Kao, Steve Muchnick, Terrence C. Miller, David Fotland, and William S. Worley.

The first implementation was the TS1, a central processing unit built from discrete transistor-transistor logic

Transistor-transistor logic

Transistor–transistor logic is a class of digital circuits built from bipolar junction transistors and resistors. It is called transistor–transistor logic because both the logic gating function and the amplifying function are performed by transistors .TTL is notable for being a widespread...

(74F TTL) devices. Later implementations were multi-chip VLSI designs fabricated in NMOS processes (NS1 and NS2) and CMOS (CS1 and PCX). They were first used in a new series of HP 3000

HP 3000

machines in the late 1980s – the 930 and 950, commonly known at the time as Spectrum systems, the name given to them in the development labs. These machines ran MPE/iX. The HP 9000

HP 9000

machines were soon upgraded with the PA-RISC processor as well, running the HP-UX

HP-UX

HP-UX is Hewlett-Packard's proprietary implementation of the Unix operating system, based on UNIX System V and first released in 1984...

version of UNIX

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

.

Other operating systems ported to the PA-RISC architecture include Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

, OpenBSD

OpenBSD

OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution , a Unix derivative developed at the University of California, Berkeley. It was forked from NetBSD by project leader Theo de Raadt in late 1995...

, NetBSD

NetBSD

NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...

and NEXTSTEP

NEXTSTEP

NeXTSTEP was the object-oriented, multitasking operating system developed by NeXT Computer to run on its range of proprietary workstation computers, such as the NeXTcube...

.

An interesting aspect of the PA-RISC line is that most of its generations have no Level 2 cache

CPU cache

A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations...

. Instead large Level 1 caches are used, formerly as separate chips connected by a bus, and now integrated on-chip. Only the PA-7100LC and PA-7300LC had L2 caches. Another innovation of the PA-RISC was the addition of vectorized instructions (SIMD

SIMD

Single instruction, multiple data , is a class of parallel computers in Flynn's taxonomy. It describes computers with multiple processing elements that perform the same operation on multiple data simultaneously...

) in the form of MAX

Multimedia Acceleration eXtensions

The Multimedia Acceleration eXtensions or MAX are instruction set extensions to the Hewlett-Packard PA-RISC instruction set architecture ....

, which were first introduced on the PA-7100LC.

The ISA was extended in 1996 to 64-bits, with this revision named PA-RISC 2.0. PA-RISC 2.0 also added fused multiply–add instructions, which help certain floating-point intensive algorithms, and the MAX-2

Multimedia Acceleration eXtensions

The Multimedia Acceleration eXtensions or MAX are instruction set extensions to the Hewlett-Packard PA-RISC instruction set architecture ....

SIMD extension, which provides instructions for accelerating multimedia applications. The first PA-RISC 2.0 implementation was the PA-8000

PA-8000

The PA-8000 , code-named Onyx, is a microprocessor developed and fabricated by Hewlett-Packard that implemented the PA-RISC 2.0 instruction set architecture . It was a completely new design with no circuitry derived from previous PA-RISC microprocessors...

, which was introduced in January 1996.

CPU specifications

Model	Marketing name	Year	Frequency [MHz]	Memory Bus [MB/s]	Process [µm]	Transistors [millions]	Die size [mm²]	Power [W]	Dcache [kB]	Icache [kB]	L2 cache [MB]	ISA
TS-1	?	1986	8	?	?	—	—	?	?	?	—	1.0
CS-1	?	1987	8	?	1.6	0.164	72.93	1	—	0.25	—	1.0
NS-1	?	1987	25/30	?	1.5	0.144	70.56	?	?	?	—	1.0
NS-2	?	1989	27.5/30	?	1.5	0.183	196	27	512	512	—	1.0
PCX	?	1990	?	?	?	?	?	?	?	?	?	1.0
PCX-S	PA-7000	1991	66	?	1.0	0.58	201.6	?	256	256	—	1.1a
PCX-T	PA-7100 PA-7100 The PA-7100 is a microprocessor developed by Hewlett-Packard that implemented the PA-RISC 1.1 instruction set architecture . It is also known as the PCX-T and by its code-name Thunderbird. It was introduced in early 1992 and was the first PA-RISC microprocessor to integrate the floating-point unit...	1992	33–100	?	0.8	0.85	196	?	2048	1024	—	1.1b
PCX-T	PA-7150	1994	125	?	0.8	0.85	196	?	2048	1024	—	1.1b
PCX-T'	PA-7200 PA-7200 The PA-7200 , code-named Thunderbird, is a microprocessor that implements the PA-RISC 1.1 instruction set architecture developed by Hewlett-Packard . It was introduced in early 1995, debuting in systems from HP...	1994	120	960	0.55	1.26	210	30	1024	2048	—	1.1c
PCX-L	PA-7100LC PA-7100LC The PA-7100LC is a microprocessor that implements the PA-RISC 1.1 instruction set architecture developed by Hewlett-Packard . It is also known as the PCX-L, and by its code-name, Hummingbird. It was designed as a low-cost microprocessor for low-end systems. The first systems to feature the...	1994	60–100	?	0.75	0.9	201.6	7–11	—	1	2	1.1d
PCX-L2	PA-7300LC	1996	132–180	?	0.5	9.2	260.1	?	64	64	0–8	1.1e
PCX-U	PA-8000 PA-8000 The PA-8000 , code-named Onyx, is a microprocessor developed and fabricated by Hewlett-Packard that implemented the PA-RISC 2.0 instruction set architecture . It was a completely new design with no circuitry derived from previous PA-RISC microprocessors...	1996	160–180	960	0.5	3.8	337.68	?	1024	1024	—	2.0
PCX-U+	PA-8200	1997	200–240	960	0.5	3.8	337.68	?	2048	2048	—	2.0
PCX-W	PA-8500	1998	300–440	1920	0.25	140	467	?	1024	512	—	2.0
PCX-W+	PA-8600	2000	360–550	1920	0.25	140	467	?	1024	512	—	2.0
PCX-W2	PA-8700(+)	2001	625–875	1920	0.18	186	304	<7.1@1.5 V	1536	768	—	2.0
Mako	PA-8800	2003	800–1000	6400	0.13	300	361	?	768/core	768/core	32	2.0
Shortfin	PA-8900	2005	800–1100	6400	0.13	?	?	?	768/core	768/core	64	2.0

External links

LostCircuits Hewlett Packard PA8800 Risc Processor overview.
HP's documentation - page down for PA-RISC, Architecture PDFs available.
OpenPA.net Comprehensive PA-RISC chip and computer information.
chipdb.org Images of different PA-RISC processors

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

History

CPU specifications

See also

External links