PA-RISC Processors

PA-8900

Overview

The PA-8900 is a slightly tweaked PA-8800 processor with a doubled L2 cache and higher clock frequency, released in 2005 only one year after the PA-8800. It is probably the last processor of the PA-RISC family, with all future systems will being based on Itanium-family chips. After HP dropped its line of Itanium workstations the PA-8900-powered C8000 were one of the last HP-UX workstations.

Information on the PA-8900 is limited, with apparently not much interest in releasing details on its architecture.

Details

PA-RISC version 2.0 64-bit
Twenty functional units: four integer ALUs, four shift/merge units, four complete load/store pipelines, four Floating Point multiply/accumulate units, four Floating Point divide/square root units
Two address adders
SMP-capable
External memory and I/O controllers
240-entry fully-associative dual-ported TLB per core
32-entry BTAC (branch target address cache) per core
2048-entry BHT (branch history table) per core
Dynamic and static branch prediction modes
4-way superscalar
0.75 MB I and 0.75 MB D on-chip L1 caches per core
64 MB off-chip L2 cache, four-way associative, physically indexed and tagged
ECC for L2 data and tags
MAX-2 multimedia extensions (subword arithmetic) for multimedia applications, e.g., MPEG decoding
Itanium 2/McKinley processor bus, 200 MHz clock (double-pumped), 128-bit datapath, 6.4 GB/s bandwidth, data ECC-protected, signals parity
CPU interfaces to the Cell chipset or the zx1 chipset’s MIO
44 bit physical addressing
64 bit virtual addressing
Four GB maximum page size
Up to 1.1 GHz frequency
23.6×15.5 mm² die, 317,000,000 FETs, 0.13µ (micron), 8-layer Silicon-on-Insulator CMOS (apparently fabbed by IBM)

Used in

rp3410, rp3440
rp4410, rp4440
rp7440, rp8440
C8000
L1500-9X (rp5430), L2000-9X (rp5450) (probably)
N4000-9X (rp7405, rp7410) (probably)
Superdome

References

Overview of the HP 9000 rp3410-2, rp3440-4, rp4410-4, and rp4440-8 Servers (PDF, 700 KB): Hewlett-Packard (2005).

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