<P> ARM Holdings periodically releases updates to architectures and core designs . All of them support a 32 - bit address space (only pre-ARMv3 chips, made before ARM Holdings was formed, as in original Acorn Archimedes, had smaller) and 32 - bit arithmetic; instructions for ARM Holdings' cores have 32 - bit fixed - length instructions, but later versions of the architecture also support a variable - length instruction set that provides both 32 - and 16 - bit instructions for improved code density . Some older cores can also provide hardware execution of Java bytecodes . The ARMv8 - A architecture, announced in October 2011, adds support for a 64 - bit address space and 64 - bit arithmetic with its new 32 - bit fixed - length instruction set . </P> <P> With over 100 billion ARM processors produced as of 2017, ARM is the most widely used instruction set architecture in terms of quantity produced . Currently, the widely used Cortex cores, older "classic" cores, and specialized SecurCore cores variants are available for each of these to include or exclude optional capabilities . </P> <P> The British computer manufacturer Acorn Computers first developed the Acorn RISC Machine architecture (ARM) in the 1980s to use in its personal computers . Its first ARM - based products were coprocessor modules for the BBC Micro series of computers . After the successful BBC Micro computer, Acorn Computers considered how to move on from the relatively simple MOS Technology 6502 processor to address business markets like the one that was soon dominated by the IBM PC, launched in 1981 . The Acorn Business Computer (ABC) plan required that a number of second processors be made to work with the BBC Micro platform, but processors such as the Motorola 68000 and National Semiconductor 32016 were considered unsuitable, and the 6502 was not powerful enough for a graphics - based user interface . </P> <P> According to Sophie Wilson, all the processors tested at that time performed about the same, with about a 4 Mbit / second bandwidth . </P>

Which is the first company who defined risc architecture