PA-RISC Processors

Hitachi HARP-1


The Hitachi HARP-1 is a PA-RISC version 1.1 compatible CPU from Hitachi, introduced in June 1994. It is apparently a larger and faster version of the PA/50 processor, however . not much information is available on either processor.

The HARP-1E variant supposedly includes (pseudo) vector processing modifications/add-ons and was used in Hitachi vector/supercomputers. It seems the L1 cache was increased to 16 KB/16 KB instruction/data.


Used in


  1. Chronology of Workstation Computers (1993) Ken Polsson (November 2007. Accessed November 2007)
  2. PROgress (PA-RISC) Newsletter - comp.sys.hp Candace Doyle (October 1993: Precision Risc Organization. Accessed December 2007)
  3. Basic Concept of Cooperative Timing-driven Design Automation Technology for High-speed RISC Processor HARP-1 (PDF) Hidekazu Terai et al (October 1999: Hitachi Ltd. Accessed January 2008)
  4. A 120- MHz BiCMOS Superscalar RISC Processor, Shigeya Tanaka et al (IEEE Journal of Solid-State Circuits, vol. 29, no. 4, April 1994)

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