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2.4 / EMBEDDED SYSTEMS AND THE ARM 49

Table 2.8 ARM Evolution

Typical MIPS
Family Notable Features Cache @ MHz
ARM1 32-bit RISC None
ARM2 Multiply and swap instructions; Integrated None 7 MIPS @ 12 MHz
memory management unit, graphics and
I/O processor
ARM3 First use of processor cache 4 KB unified 12 MIPS @ 25 MHz
ARM6 First to support 32-bit addresses; floating-point 4 KB unified 28 MIPS @ 33 MHz
unit
ARM7 Integrated SoC 8 KB unified 60 MIPS @ 60 MHz
ARM8 5-stage pipeline; static branch prediction 8 KB unified 84 MIPS @ 72 MHz
ARM9 16 KB/16 KB 300 MIPS @ 300 MHz
ARM9E Enhanced DSP instructions 16 KB/16 KB 220 MIPS @ 200 MHz
ARM10E 6-stage pipeline 32 KB/32 KB
ARM11 9-stage pipeline Variable 740 MIPS @ 665 MHz
Cortex 13-stage superscalar pipeline Variable 2000 MIPS @ 1 GHz
XScale Applications processor; 7-stage pipeline 32 KB/32 KB L1 1000 MIPS @ 1.25 GHz
512 KB L2

DSP = digital signal processor
SoC = system on a chip

British Broadcasting Corporation (BBC) to develop a new microcomputer architec-
ture for the BBC Computer Literacy Project. The success of this contract enabled
Acorn to go on to develop the first commercial RISC processor, the Acorn RISC
Machine (ARM). The first version, ARM1, became operational in 1985 and was
used for internal research and development as well as being used as a coprocessor in
the BBC machine.Also in 1985,Acorn released the ARM2, which had greater func-
tionality and speed within the same physical space. Further improvements were
achieved with the release in 1989 of the ARM3.
Throughout this period, Acorn used the company VLSI Technology to do the
actual fabrication of the processor chips.VLSI was licensed to market the chip on its
own and had some success in getting other companies to use the ARM in their prod-
ucts, particularly as an embedded processor.
The ARM design matched a growing commercial need for a high-performance,
low-power-consumption, small-size and low-cost processor for embedded applica-
tions. But further development was beyond the scope of Acorns capabilities.
Accordingly, a new company was organized, with Acorn, VLSI, and Apple Com-
puter as founding partners, known as ARM Ltd. The Acorn RISC Machine became
10
the Advanced RISC Machine. The new company’s first offering, an improvement
on the ARM3, was designated ARM6. Subsequently, the company has introduced a
number of new families, with increasing functionality and performance. Table 2.8

10 The company dropped the designation Advanced RISC Machine in the late 1990s. It is now simply
known as the ARM architecture.