Blitzkrieg: ARM: Advanced RISC Machines

The ARM is a 32-bit reduced instruction set computer (RISC) instruction set architecture (ISA) developed by ARM Limited .
The ARM architecture is the most widely used 32-bit ISA - It is implemented in many microprocessors and microcontrollers for embedded systems.
Because many ARM processors consume little power, they are dominant in the mobile electronics market, where low-power consumption is a critical design goal.
As of 2009, ARM processors account for approximately 90% of all embedded 32-bit RISC processors. ARM processors are used extensively in consumer electronics, including PDAs, mobile phones, iPods and other digital media and music players, hand-held game consoles, calculators and computer peripherals such as hard drives and routers.

ARM processors were originally designed for desktop personal computers. The ARM design was started in 1983 as a development project at Acorn Computers Ltd to build a compact RISC CPU.
The team completed development samples called ARM1 by April 1985,and the first "real" production systems as ARM2 the following year.
The ARM2 was possibly the simplest useful 32-bit microprocessor in the world, with only 30,000 transistors.
The ARM2 featured a 32-bit data bus, a 26-bit (64 Mbyte) address space and sixteen 32-bit registers. Program code had to lie within the first 64 Mbyte of the memory, as the program counter was limited to 26 bits because the top 6 bits of the 32-bit register served as status flags.

A successor, ARM3, was produced with a 4KB cache, which further improved performance. The new Apple-ARM work would eventually turn into the ARM6, first released in early 1992.
Intel took the opportunity to supplement their aging i960 line with the StrongARM. Intel later developed its own high performance implementation known as XScale which it has since sold to Marvell.
ARM's business has always been to sell IP cores, which licensees use to create microcontrollers and CPUs based on this core.
The most successful implementation has been the ARM7TDMI with hundreds of millions sold in almost every kind of microcontroller equipped device.
ARM licensed about 1.6 billion cores in 2005. In 2005, about 1 billion ARM cores went into mobile phones. As of January 2008, over 10 billion ARM cores have been built, and iSuppli predicts that 5 billion a year will ship in 2011.
ARM: Advanced RISC Machines

Blitzkrieg