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From what I've heard, there are a lot of incompatible ISA implementations of RISC-V. Raspberry Pi adopting a specific ISA might be a tipping point in RISC-V ad

From what I've heard, there are a lot of incompatible ISA implementations of RISC-V. Raspberry Pi adopting a specific ISA might be a tipping point in RISC-V adoption.

snvzz 3y ago
>there are a lot of incompatible ISA implementations of RISC-V That is a form of FUD that unfortunately shows up very often. In reality, all known application processors (e.g. made to run a software stack based on Linux), follow the RVA profile[0] spec. So do all Linux binary distributions known to support RISC-V. As well as the BSDs. Specifically, they currently target RVA20, and thus also support RVA22. 0. https://github.com/riscv/riscv-profiles/releases https://github.com/riscv/riscv-profiles/releases
- cptskippy 3y ago
  I'm not disagreeing with you that it's a bit of FUD, however what you're saying isn't entirely true either. > In reality, all known application processors (e.g. made to run a software stack based on Linux), follow the RVA profile[0] spec. What profile does Greenwave's GAP8 conform to? > Specifically, they currently target RVA20, and thus also support RVA22. Anything targeting RVA20 wouldn't be forward compatible. RVA22 added vector and floating-point extensions that a processor conforming to RVA20 wouldn't necessarily have or that wouldn't necessarily be compatible with RVA22.
  - snvzz 3y ago
    >What profile does Greenwave's GAP8 conform to? That's a microcontroller, and designed to run your custom code. Regardless, it does conform to RVI20 profile, and supports the optional M and C extensions. It will thus run RVI20 code w/o issue. >or that wouldn't necessarily be compatible with RVA22. If not clear enough, all RVA20 code runs unmodified on RVA22.
    - cptskippy 3y ago
      > That's a microcontroller, and designed to run your custom code. It is specifically marketed as an application processor. > If not clear enough, all RVA20 code runs unmodified on RVA22. Sorry I misunderstood what you were saying. I thought you meant software targeting RVA22 would run on a RVA20 processor.

From what I've heard, there are a lot of incompatible ISA implementations of RISC-V. Raspberry Pi adopting a specific ISA might be a tipping point in RISC-V adoption.

snvzz 3y ago

>there are a lot of incompatible ISA implementations of RISC-V That is a form of FUD that unfortunately shows up very often. In reality, all known application processors (e.g. made to run a software stack based on Linux), follow the RVA profile[0] spec. So do all Linux binary distributions known to support RISC-V. As well as the BSDs. Specifically, they currently target RVA20, and thus also support RVA22. 0. https://github.com/riscv/riscv-profiles/releases https://github.com/riscv/riscv-profiles/releases

cptskippy 3y ago
I'm not disagreeing with you that it's a bit of FUD, however what you're saying isn't entirely true either. > In reality, all known application processors (e.g. made to run a software stack based on Linux), follow the RVA profile[0] spec. What profile does Greenwave's GAP8 conform to? > Specifically, they currently target RVA20, and thus also support RVA22. Anything targeting RVA20 wouldn't be forward compatible. RVA22 added vector and floating-point extensions that a processor conforming to RVA20 wouldn't necessarily have or that wouldn't necessarily be compatible with RVA22.
- snvzz 3y ago
  >What profile does Greenwave's GAP8 conform to? That's a microcontroller, and designed to run your custom code. Regardless, it does conform to RVI20 profile, and supports the optional M and C extensions. It will thus run RVI20 code w/o issue. >or that wouldn't necessarily be compatible with RVA22. If not clear enough, all RVA20 code runs unmodified on RVA22.
  - cptskippy 3y ago
    > That's a microcontroller, and designed to run your custom code. It is specifically marketed as an application processor. > If not clear enough, all RVA20 code runs unmodified on RVA22. Sorry I misunderstood what you were saying. I thought you meant software targeting RVA22 would run on a RVA20 processor.