Apollo PRISM Processor
PRISM was a RISC processor developed by Apollo Computer Inc. during the 1980s and released in 1988. PRISM was the first commercial CPU architecture to include a VLIW (Very Long Instruction Word) design and was implemented on CMOS on a processor board consisting of eight VLSI chips. For the time, PRISM was billed as one of the fastest RISC processors, and was able to support up two four CPUs in a single system (SMP).
The processors were used in Apollo's own Domain 10000 line of computers, with a PRISM II processor already being planned and designed. After the acquisition by HP in 1989, the Apollo products were integrated into the HP line up, but the PRISM II processor dropped. Parts of the PRISM architecture were later reused in PA-RISC, including the FPU.
PRISM was sometimes codenamed A88K (or a88k), not to be confused with the Motorola M88K 88000 RISC processors, after Apollo earlier used Motorola 68000 processors in its workstations.
- PRISM RISC/VLIW architecture, 32-bit
- CPU is a single chip with seven VLSI chips
- FPU from BIT (Bipolar Integrated Technologies)
- MMU from Toshiba (CMOS)
- Computing units:
- Integer/load/store unit
- Floating point multiplier
- Floating point add/subtract unit.
- Two 32-bit integer registers, 32 floating point registes
- Cache L1 128 KB instruction and 64 KB data off-chip
- Shared virtual memory multiprocessing
- Up to 720 MB main memory could be addressed in a single system
- CPU attaches via X-Bus to memory, I/O and graphics controllers, 64-bit bus, 150 Mb/s data rate
- Clock speed 20 MHz
- One circuit board, CPU implemented in CMOS, seven chips 1.5µ VLSI CMOS
- APOLLO COMPUTER LAUNCHES ITS 64-BIT PRISM RISC MACHINE, Tech Monitor archive, February 29, 1988
- WHY APOLLO COMPUTER RECKONS IT HAS OUTDONE SUN IN THE RISC STAKES, Tech Monitor archive, March 14, 1988
- Apollo CPUs, Apollo/DOMAIN Computers at zepa.net, 2003 (archive.org mirror from 20030201)