ARM,
ARM was originally designed by a group of mathematicians for use in a relatively obscure proprietary personal computer system. This core presently dominates the low end of the 32-bit market (in terms of shipment volumes) due in part to low power requirements, wide availability in many forms, and a clever instruction set architecture. For example, the so-called "Thumb" instruction set extension allows the microcontroller, though 32-bit in nature, to run quite efficiently out of 16-bit memories with about a 25% improvement in code density. (Narrower data buses generally imply a lower pin count on the microcontroller, and hence a lower cost). Thumb code can also be used in pure 32-bit hardware designs to reduce code volume significantly without unacceptably influencing execution speed. In the last two years or thereabouts, we have begun to see very cut-down ARM-based parts with a small amount of on-chip flash and RAM making their way into control applications formerly occupied by 8-bit devices. ARM is also the most common core used in PDA and smartphone applications. from: http://www-106.ibm.com/developerworks/library/pa-migrate/?ca=dgr-lnxw06X86ToPower#Resources| ARM, | | 2005.01.06-11:33.00
