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In 2004, ARM announced its newest generation of licensable cores, called the “Cortex” family.  Cortex cores span a wide range of performance levels, with Cortex M-series cores at the low end, Cortex R-series cores providing mid-range performance, and the Cortex A-series applications processors offering the highest performance.  The first Cortex core to be announced was the Cortex-M3, and since then ARM has announced several others, including the Cortex-A8 and A9, the Cortex-M1, and the Cortex-R4.

The Cortex-R4 targets moderately demanding applications such as hard disk drives, inkjet printers, automotive safety systems, and wireless modems. It is marketed as a higher-performance replacement for the older ARM9E core. BDTI recently completed a benchmark analysis of the ARM Cortex-R4 core and is now releasing the first independent signal processing benchmark results for this processor. In this article, we’ll take a look at its benchmark results and compare its performance to that of other ARM cores (including the ARM11, another moderate-performance core) and selected competitors.

Table 1 summarizes key attributes of selected ARM processor cores.

Table 1. Characteristics of selected ARM cores.

*Clock speed data provided by ARM, not verified by BDTI. Clock speeds for ARM9E and ARM11 are worst-case speeds in a TSMC CL013G process and ARM Artisan SAGE-X library. Clock speed for Cortex-R4 is worst-case for a 90 nm CLN90G Artisan Advantage implementation. High-end clock speed for Cortex-A8 is based on a custom implementation.

As shown in Table 1, the Cortex-R4 is a superscalar core that can issue and execute up to two instructions per cycle. Like the Cortex-A8, it supports the ARMv7 instruction set architecture and the Thumb2 compressed instruction set, but the Cortex-R4 does not support the NEON signal processing extensions.  As a result, its signal processing capabilities and features are much more limited than those of the Cortex-A8.