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| Mako || [[PA-8800#PA-8800|PA-8800]] ||2003||800–1000||6400||0.13||300||361||?||768/core||768/core||32||2.0
| Mako || [[PA-8800#PA-8800|PA-8800]] ||2003||800–1000||6400||0.13||300||361||?||768/core||768/core||32||2.0
|-
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| Shortfin || [[PA-8000#PA-8900|PA-8900]] ||2005||800–1100||6400||0.13||?||?||?||768/core||768/core||64||2.0
| Shortfin || [[PA-8000#PA-8900|PA-8900]] ||2005||800–1100||6400||0.13||?||?||~35@1.0Ghz||768/core||768/core||64||2.0
|}
|}


Revision as of 10:35, 22 July 2009

PA-RISC (HP/PA)
DesignerHewlett-Packard
Bits64-bit (32→64)
Introduced1986 (1996 PA-RISC 2.0)
Version2.0 (1996)
DesignRISC
EncodingFixed
BranchingCompare and branch
EndiannessBig
ExtensionsMultimedia Acceleration eXtensions (MAX), MAX-2
OpenNo
Registers
General-purpose32 64-bit
Floating point32 64-bit
HP PA-RISC 7300LC Microprocessor

PA-RISC is an instruction set architecture (ISA) developed by Hewlett-Packard's Systems & VLSI Technology Operation. As the name implies, it is a Reduced Instruction Set Computing (RISC) architecture, where the PA stands for Precision Architecture. The design is also referred to as HP/PA for Hewlett Packard Precision Architecture. PA may also refer to Palo Alto, California, the location of HP's headquarters.

The architecture was introduced on 26 February 1986 when the HP 3000 Series 930 and HP 9000 Model 840 computers were launched featuring the first implementation, the TS1.[1][2]

HP stopped selling PA-RISC-based HP 9000 systems at the end of 2008 but will support servers running PA-RISC chips until 2013.[3] Newer Itanium-based machines are intended to succeed PA-RISC in its market segment.[4]

History

In the late 1980s HP was building four series of computers, all based on CISC CPUs. One line was the IBM PC compatible Intel i286 based Vectra Series started 1986. All others were non-Intel systems. One of them was the HP Series 300 of Motorola 68000-based workstations (in 1990 they had one additional 68000-based Series, the new HP Apollo Series 400, a workstation line they took over when they purchased Apollo Computer in 1989), another Series 200 line of technical workstations based on a custom silicon on sapphire (SOS) chip design, the SOS based 16-bit HP 3000 classic series and finally the HP 9000 Series 500 minicomputers, based on their own (16 and 32-bit) FOCUS CPU. 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 and William S. Worley.[5]

The first implementation was the TS1 a central processing unit built from discrete transistor-transistor logic (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 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 machines were soon upgraded with the PA-RISC processor as well, running the HP-UX version of UNIX.

Other operating systems ported to the PA-RISC architecture include Linux, OpenBSD, NetBSD, NEXTSTEP, and an unreleased Windows NT[6].

An interesting aspect of the PA-RISC line is that most of its generations have no Level 2 cache. 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) in the form of MAX 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 helps certain floating-point intensive algorithms, and the MAX-2 SIMD extension, which provides instructions for accelerating multimedia applications. The first PA-RISC 2.0 implementation was the PA-8000, which was introduced in January 1996.

PA-RISC microprocessor 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
PCX-S PA-7000 1989 66 ? 1.0 0.58 201.6 ? 256 256 — 1.1a
PCX-T PA-7100 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 1994 120 960 0.55 1.26 210 30 1024 2048 — 1.1c
PCX-L PA-7100LC 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 1996 160–180 960 0.5 3.8 338/347? ? 1024 1024 — 2.0
PCX-U+ PA-8200 1997 200–240 960 0.5 3.8/4.5? 338/347? ? 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 480–552 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 ? ? ~35@1.0Ghz 768/core 768/core 64 2.0

See also

References

  1. ^ "One Year Ago". (26 February 1987). Computer Business Review.
  2. ^ Hewlett-Packard Company (September 1987). Hewlett-Packard Journal 38 (9): p. 3.
  3. ^ How long will HP continue to support HP 9000 systems?
  4. ^ HP Completes Its PA-RISC Road Map With Final Processor Upgrade - PA-RISC Processor
  5. ^ Smotherman, Mark (2 July 2009). Recent Processor Architects.
  6. ^ There were several rumors in the mid-1990s which mention an HP-internal/unreleased Windows NT port to PA-RISC, cf. for one example Re: Windows NT for PA-RISC, David Peter (comp.sys.hp.apps USENET post December 1995)
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