The processor cores described in this chapter are well tuned for embedded systems.
They are SuperH TM RISC engine family processor cores (SH cores) as typical
embedded CPU cores, flexible engine/generic ALU array (FE-GA or shortly called
FE as flexible engine) as a reconfigurable processor core, MX core as a massively
parallel SIMD-type processor, and video processing unit (VPU) as a video processing
accelerator. We can implement heterogeneous multicore processor chips with them,
and three implemented prototype chips, RP-1, RP-2, and RP-X, are introduced in
the Chap. 4 .
Embedded CPU Cores
Since the beginning of the microprocessor history, a processor especially for PC/
servers had continuously advanced its performance while maintaining a price range
from hundreds to thousands of dollars [ 1, 2 ]. On the other hand, a single chip micro-
controller had continuously reduced its price resulting in the range from dozens of
cents to several dollars with maintaining its performance and had been equipped to
various products [ 3 ]. As a result, there was a situation of no demand on the proces-
sor of the middle price range from tens to hundreds of dollars.
However, with the introduction of the home game console in the late 1980s and
the digitization of the home electronic appliances from the 1990s, there occurred the
demands to a processor suitable for multimedia processing in this price range.
Instead of seeking high performance, such a processor has attached great impor-
tance to high efficiency. For example, the performance is 1/10 of a processor for
PCs, but the price is 1/100, or the performance equals to a processor for PCs for the
important function of the product, but the price is 1/10. The improvement of area
efficiency has become the important issue in such a processor.
In the late 1990s, a high-performance processor consumed too high power for
mobile devices such as cellar phones and digital cameras, and the demand was