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> The most significant change...fully custom Arm CPU > All subsequent versions...have been tweaked versions of off-the-shelf Arm Cortex processors rather than
by uticus 3y ago
> The most significant change...fully custom Arm CPU
> All subsequent versions...have been tweaked versions of off-the-shelf Arm Cortex processors rather than fully custom designs.
I thought ARM was licensed? What does this mean, there are off-the-shelf processors and there are also fully custom designs?
- pjmlp 3y agoYes, since forever. Some OEMs take ARM's design as they are, others design them further, Samsung's Exynos is another example.
- uticus 3y agoI see. I'm more familiar with the software side of things, this sounds analogous to open source licenses encountered there.
- PaulHoule 3y agoThe ARM IP is multifaceted. There's the instruction set. There are chip designs at various levels of detail that a licensee can use or modify to make their own chips. There are tons of patents, see https://patents.justia.com/assignee/arm-limited https://patents.justia.com/assignee/arm-limited and of course trademarks, such as "ARM" itself.
- wongarsu 3y agoIn a sense ARM is like a big open source project, with component libraries and production-ready example projects. It's less open in the sense that you need NDAs and license payments, but the flexibility is similar.
- pjmlp 3y agoThe libraries being Verilog, or whatever they use for their chip design.
- jarym 3y agoARM also sell designs so vendors can build systems at a lower cost. But you can also license the technology and make your own design (which is what Apple did)
- rsynnott 3y agoAs I understand it, there are roughly three levels. You can license ARM-designed cores and put them, largely unchanged, in your SoC (eg most current Qualcomm chips). You can license ARM-designed cores and make changes, and put them in your SoC (eg the Apple A4/5). Or you can license the _instruction set architecture_ and design your own completely different core which complies to that ISA (eg modern Apple cores, some old Qualcomm cores, this new Qualcomm core).