VIPER is a 32-bit

microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...

design created by

Royal Signals and Radar Establishment The Royal Signals and Radar Establishment (RSRE) was a scientific research establishment within the Ministry of Defence (MoD) of the United Kingdom. It was located primarily at Malvern in Worcestershire, England. The RSRE motto was ''Ubique S ...

(RSRE) in the 1980s, intended to be used in

safety-critical A safety-critical system (SCS) or life-critical system is a system whose failure or malfunction may result in one (or more) of the following outcomes: * death or serious injury to people * loss or severe damage to equipment/property * environme ...

systems such as

avionics Avionics (a blend word, blend of ''aviation'' and ''electronics'') are the Electronics, electronic systems used on aircraft. Avionic systems include communications, Air navigation, navigation, the display and management of multiple systems, ...

. It was the first commercial microprocessor design to be formally proven correct, although there was some controversy surrounding this claim and the definition of proof. The design was completed in 1987 and implemented initially by RSRE in a gate array. Marconi Electronics subsequently licensed the design, implementing it as the MAS1908 VIPER-1, fabricated using CMOS and silicon-on-sapphire technologies, being packaged as a 120-pin grid array product. Architecturally, VIPER is a 32-bit processor supporting 20-bit word-oriented addressing of memory and of "I/O space" (and thus 4 megabytes of each). Although employing a uniform instruction layout suggestive of RISC architectures, instruction execution times vary from 6 to 26 clock cycles, in contrast to a throughput of one instruction per cycle sought by conventional RISC architectures. A safety critical programming language named Newspeak was designed by Ian Currie of RSRE in 1984 for use with VIPER. Its principal characteristic was that all exceptional behaviour in programs must be dealt with at compile time.

References

External links

MacKenzie, Donald ''Knowing Machines - Essays on Technical Change''
History of computing in the United Kingdom Malvern, Worcestershire Proof theory Science and technology in Worcestershire 32-bit microprocessors {{Microcompu-stub