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Architecture license means you can use the ISA (provided by Arm). Micro arch means you can license the core implementations form Arm. Apple is an ISA license, m

Architecture license means you can use the ISA (provided by Arm). Micro arch means you can license the core implementations form Arm. Apple is an ISA license, meaning they have full control of the micro arch as long as it passes verification by Arm. That’s the beauty of Arm, you get rid of the problem of creating the whole software ecosystem...it’s already there, and companies like Cavium, Apple, Qualcomm are free to add their secret sauce and benefit from the mature software environment. At least, that’s the hope.

sspiff 9y ago
Prior to ARMv8, all licensees could add additional specialized instructions or even entire instruction sets using the ARM coprocessor model. By changing a few registers, you could alter how instructions were interpreted. This was used by some vendors for hardware-software interfacing, and by others to provide specific acceleration primitives for their specialized workloads. ARM used this mechanism themselves to offer an optional floating point unit, with specialized vectorized floating point instructions. Unfortunately, support for coprocessors has been removed from ARMv8.