3 ms·
Have you ever noticed that ARMv8-A architecture extensions are published faster than Arm-designed cores make use of them? I'm pretty sure thats because archite
by repiret 6y ago
Have you ever noticed that ARMv8-A architecture extensions are published faster than Arm-designed cores make use of them? I'm pretty sure thats because architecture licensees are a major driver of those extensions. If Apple needs a CPU that adds X and Y to the architecture and removes Z, I have no doubt that Arm will work with them to allow it, and that it will probably come in the form of an architecture extension that permits it. Arm gets as much from Apple out of the relationship as Apple gets from Arm, and Arm surely knows it. They don't benefit from bossing Apple around.
Arm very recently started allowing Core licensees to add custom instructions (on M33 and M55). But they've allowed architecture licensees to do that for a long time (see XScale).
- rrss 6y agoYeah, agreed that architectural licensees definitely influence future ARM specifications - e.g. Fujitsu was a major driver behind SVE. IMO, there's an important difference between Apple adding new instructions that are not in the spec, and Apple convincing ARM to add new instructions to the spec and then implementing those instructions. In the first case, those are Apple-only instructions. In the second, that's just Apple implementing new ARM instructions. > But they've allowed architecture licensees to do that for a long time I don't agree that developing specifications and extensions based on the needs and desires of licensees is the same as permitting licensees to add custom instructions not permitted by the specification. > They don't benefit from bossing Apple around ARM benefits greatly from limiting fragmentation of their platform by exerting control over licensees.