5 ms·

Or let me ask in different way: why use ARM if you control and build the whole stack from electronics to operating system to the software running on it? The co

by chvid 6y ago

Or let me ask in different way: why use ARM if you control and build the whole stack from electronics to operating system to the software running on it? The core instruction set is from the 80es. Surely you can come up with some better today were you to design it from scratch?

Alupis 6y ago
> Surely you can come up with some better today were you to design it from scratch? Ya, but then you have to develop and support the entire ecosystem around just the instruction set. That means compilers, languages, runtimes, and more - which is not a trivial undertaking. Perhaps Apple could pull it off, but it would take a very long time to get something entirely new stable enough, and performant enough, to compete with anything being offered today. Plus, it's not Apple's focus and doesn't really benefit them much either. Nobody builds iOS apps in assembler - but they expect it to run fast. That takes a very well tuned compiler, and a very well refined CPU architecture.
mjw1007 6y ago
The 64-bit ARM ISA was basically redone from scratch, around 2010. It isn't "mostly the same instructions but with 64-bit registers" the way 64-bit x86 is.
- earthscienceman 6y ago
  Do you (or anyone else) know where I can read about that?
  - mjw1007 6y ago
    The reference manual is at https://developer.arm.com/documentation/ddi0487/latest/ https://developer.arm.com/documentation/ddi0487/latest/
  - trasz 6y ago
    Just google for "ARMv8". (Also, it's not like ARM was a single instruction set before either. For quite some time ARM had two totally different instruction encodings, the "usual one", and Thumb2, with microcontrollers usually only supporting the latter.)
nicoburns 6y ago
> why use ARM if you control and build the whole stack from electronics to operating system to the software running on it? Why not use ARM if the alternative is to build an entire software stack from scratch. ARMs licensing fees are very reasonable, and then you get most of the free software ecosystem for free.

by chvid 6y ago

Alupis 6y ago

> Surely you can come up with some better today were you to design it from scratch? Ya, but then you have to develop and support the entire ecosystem around just the instruction set. That means compilers, languages, runtimes, and more - which is not a trivial undertaking. Perhaps Apple could pull it off, but it would take a very long time to get something entirely new stable enough, and performant enough, to compete with anything being offered today. Plus, it's not Apple's focus and doesn't really benefit them much either. Nobody builds iOS apps in assembler - but they expect it to run fast. That takes a very well tuned compiler, and a very well refined CPU architecture.

mjw1007 6y ago

The 64-bit ARM ISA was basically redone from scratch, around 2010. It isn't "mostly the same instructions but with 64-bit registers" the way 64-bit x86 is.

earthscienceman 6y ago
Do you (or anyone else) know where I can read about that?
- mjw1007 6y ago
  The reference manual is at https://developer.arm.com/documentation/ddi0487/latest/ https://developer.arm.com/documentation/ddi0487/latest/
- trasz 6y ago
  Just google for "ARMv8". (Also, it's not like ARM was a single instruction set before either. For quite some time ARM had two totally different instruction encodings, the "usual one", and Thumb2, with microcontrollers usually only supporting the latter.)

nicoburns 6y ago

> why use ARM if you control and build the whole stack from electronics to operating system to the software running on it? Why not use ARM if the alternative is to build an entire software stack from scratch. ARMs licensing fees are very reasonable, and then you get most of the free software ecosystem for free.