Researched
RISC Processors & ARM
IBM, Berkeley and Stanford showed in 1980-84 that a processor with few simple instructions runs fast; Acorn's ARM1 (1985) made the idea frugal, and ARM designs now sit in nearly every smartphone.
Open in the interactive tree →John Cocke's IBM 801 (completed 1980), Patterson's Berkeley RISC-I (1982, about 44,000 transistors) and Hennessy's Stanford MIPS (working in 1983) each reduced the instruction set to simple register operations that pipeline easily. Acorn in Cambridge began its ARM project in October 1983, and the first ARM1 silicon was tested on 26 April 1985. Arm was spun out in 1990 and licenses designs instead of selling chips, so many firms build them: about 98% of mobile phones sold in 2005 and 95% of smartphones in 2010 used an ARM processor.
Prerequisites
- Programming Languages1957Compilers for high-level languages mostly used simple instructions, which RISC kept.
- Microprocessor1971RISC rethought the single-chip processor that the 4004 began.
Unlocks
- Smartphone2007Phone processors are low-power ARM designs.