A future of customizable processors: are we there yet?

Customizable processors are being used increasingly often in SoC designs. During the past few years, they have proven to be a good way to solve the conflicting flexibility and performance requirements of embedded systems design. While their usefulness has been demonstrated in a wide range of products, a few challenges remain to be addressed: 1) Is extending a standard core template the right way to customization, or is it preferable to design a fully customized core from scratch? 2) Is the automation offered by current toolchains, in particular generation of complex instructions and their reuse, enough for what users would like to see? 3) And when we look at the future with the increasing use of multi-processor SoCs, do we see a sea of identical customized processors, or a heterogeneous mix? We comment and elaborate here on these challenges and open questions.