Per [Wikipedia](https://en.wikipedia.org/wiki/ARM_architecture) the ARM architecture is developed by Arm Holdings, a British company. Given that the Apple M1 chip is an ARM-based chip, did Apple simply do minor customization on work mostly done by Arm Holdings or did it actually design substantial elements of the new chip?
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The license is needed for the instruction set architecture, not necessarily for the implementation.
Ex. if the ISA states that when the multiplication instruction (which is encoded in such and such a manner) is executed, register C should contain A*B, it doesn’t really matter how the multiplication itself is calculated. You can have a complex multiplier circuit. This would produce the correct result.
or the processor could internally do a loop for A times, adding B each time. This would also produce the correct result, albeit extremely inefficiently.
The program cannot tell the difference, because as far as it’s concerned, an instruction is one whole indivisible thing. As long as whatever it expects to happen, happens, the program will execute correctly.
As long as the processor can understand the ARM instruction set and produce the correct result for each instruction, then Apple is free to design their own implementation completely from scratch (which they probably did) and call it an ARM processor.
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