> ...one last gap remains in the middle of this stack of system exclusivity: Apple licenses the instruction set architecture for its mobile devices from ARM.
But Apple already not only designs the own SoCs independently already, they regularly add their own opcodes to the ARM instruction sets they license, as they see fit.
The alternative to not licensing from ARM, even if they "invented their own ISA", would be to pay an exorbitant sum in royalties to ARM and every other patent-holder whose technology they might dare use in their chip. So paying ARM for their technology in one go just makes the most economical/legal sense.
The crux of the article is:
> ...one last gap remains in the middle of this stack of system exclusivity: Apple licenses the instruction set architecture for its mobile devices from ARM.
But Apple already not only designs the own SoCs independently already, they regularly add their own opcodes to the ARM instruction sets they license, as they see fit.
The alternative to not licensing from ARM, even if they "invented their own ISA", would be to pay an exorbitant sum in royalties to ARM and every other patent-holder whose technology they might dare use in their chip. So paying ARM for their technology in one go just makes the most economical/legal sense.