Time was when a great many companies had their own processor architectures. It was a pinnacle of electronic and semiconductor achievement and many digital engineers wanted to have a crack at designing one and feeling the glow of watching software execute on an electronic machine of their own devising.
As we know, success breeds volume and volume provides cash to keep chip development riding the down escalator that is Moore's Law.
Intel has been successful as has ARM. Other architectures are available, as well as multiple implementers. And then there is the application-specific specialization of processors for such things as graphics rendering and other activities.
The system-on-chip era, where the processor is just one part of a larger application-specific chip, changed the business dynamic. Gradually, more and more companies have started to gain time-to-market and cost advantages over their competition by licensing a pre-developed processor core from MIPS, ARC, ARM, Imagination and some others. But of these, ARM has been the most successful by far.
But what happens when everyone is designing their SoCs with cores licensed from ARM? Where is the differentiation? Where is the time to market advantage?
One could argue that there is scope for differentiation in how the system-chip is put together, and that the cores are like the bricks of a house. For example, Nvidia has built a quad-core Cortex-A15 system-chip for mobile applications called Tegra 4, which integrates a fifth processor for low-power standby operation. Samsung's Exynos 5 Octa is also a quad-core Cortex-A15 design but one that adopts fully the "big-little" power saving approach with a quad-core Cortex-A7. But is that enough differentiation?
If you are using ARM-defined cores and ARM processor optimization packages to develop your chips. you are essentially on the same time-to-market line as everybody else in the world, unless you are one of the lead partners that helps ARM develop the core in the first place. And if you are helping develop the core in the first place maybe you would do better developing that for yourself alone under an architecture license.
This argument could be one of the reasons we are starting to see a rush of ARM architecture licensees coming forward, although it is interesting to note this is predominantly (exclusively?) with companies based in the western hemisphere.
The best known is probably Apple. But Qualcomm has also developed its own ARM-compatible processing architecture called Krait. Broadcom recently announced it had taken architectural licensees for both the ARMv7 and the 64-bit capable ARMv8 instruction set architectures. As ARM moves up to 64-bit computing, the number of architectural licenses seems to have increased with Applied Micro and Cavium both going down the route that allows differentiation at both the processor core and the system-chip level.