5 ms·

So does Applied Micro, Broadcom, Cavium, Huawei, Nvidia, AMD, Samsung, Marvell, Microsoft, Qualcomm, Intel, Faraday

• monocasa 4y ago
  Apple has something deeper than the architectural license the others listed have. They've gone further with changes than others are allowed to.
  • MikusR 4y ago
    I have seen comments saying that but no sources.
    • monocasa 4y ago
      It's widely been stated including by Arm that architectural license holders must still fully comply with the Arm Architecture Reference Manual. Apple's Arm cores do not.
      • dagmx 4y ago
        In what way are they non conforming?
        • monocasa 4y ago
          Dozens of different ways. New instructions, new privilege modes, VHE mode in EL2 can't be turned off, etc.
          • msbarnett 4y ago
            Obviously some of those are intentional architectural deviations, but is there a good reason to believe the stuck HCR_EL2.E2H bit isn't just an errata?
          • saagarjha 4y ago
            None of those are exposed to applications or in open source, are they?
  • kramerger 4y ago
    This is not true.
    • monocasa 4y ago
      Which part? I could come up with a half dozen ways off of the top of my mins that the M1 cores don't comply with the Arm ARM. Not being able to turn of VHE in EL2 is one example. And Arm has stated widely that architectural license holders have to comply with the Arm ARM still.
      • kramerger 4y ago
        You are assuming that no other company has this type of license or has done this type of architectural changes. That is not true. See monocasa's comment.
        • monocasa 4y ago
          I am monocasa; that was my comment. And the reason that I'm assuming that no one else has the same 'special relationship' is that it's a not well kept secret that Apple designed large parts of the base AArch64 with ARM and simply owns the IP on large parts of the ISA, similar to how at this point both AMD and Intel practically own x86 due to their different contributions over the years. Qualcomm, et al can not say the same.
          • kramerger 4y ago
            Huh, I meant MikusR :( Anyway, I think my comment is still valid. The "special relationship" is just fanboy fantasy. Qualcomm and Marvell have both in past done ground up designs that significantly differs from any ARM silicon. If you don't believe me, fell free to provide actual proof of this special license.
            • monocasa 4y ago
              It's been posted elsewhere, diverging from the ARM Architecture Reference Manual in ways that other chips have not. New instructions in spaces like ML, decompression, new privilege modes, features that are fixed on that are specficed to be optional at runtime, etc. Particularly the new instructions are damning as ARM has said they are specifically disallowing custom instructions this go around in order to combat architecture fragmentation.
• jeffbee 4y ago
  AppliedMicro's architectural license is now held by Ampere.