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Ubuntu 24.04 LTS exists and needs only RV64GC and will be supported and enhanced for many more years. Debian has no plans to require more than RV64GC. RVA23 i

Ubuntu 24.04 LTS exists and needs only RV64GC and will be supported and enhanced for many more years. Debian has no plans to require more than RV64GC. RVA23 is a very good thing in certain markets, but nothing forces you to support it for a personal project.

boredatoms 2mo ago
I cant see debian remaining on rv64gc later on when enough rva23 boards are purchasable
- brucehoult 2mo ago
  Why? It'll still run fine. Just like Debian still runs on original x86-64-v1 from 1999, not x86-64-v3 (needs AVX2,FMA, BMI1, BMI2, LZCNT) or even x86-64-v3 (needs AVX-512). Similarly, Debian for arm64 still requires only ARMv8.0-A from 2011 not even ARMv8.2-A (everything from A75/A55 to A78/N1/V1) let alone ARMv9-A (A710, A510, X2 and on). Why would they do in the RISC-V world what they totally haven't done in amd64 or arm64?
  - camel-cdr 2mo ago
    No, debian requires ARMv8.0-A + FP + NEON, as those are optinal extensions (even optional in ARMv9.0-A)
    - brucehoult 2mo ago
      SVE2 is compulsory in ARMv9-A, but NEON is optional?
      - camel-cdr 2mo ago
        https://support.arm.com/documentation/109697/2026_06/Feature-descriptions/The-Armv9-0-architecture-extension https://support.arm.com/documentation/109697/2026_06/Feature... > In an Armv9.0 implementation, if FEAT_FP and FEAT_AdvSIMD are implemented, the following features are implemented: ... This implies they don't have to be implemented. https://support.arm.com/documentation/109697/2026_06/Feature-descriptions/The-Armv8-0-architecture-extension https://support.arm.com/documentation/109697/2026_06/Feature... > FEAT_FP is OPTIONAL from Armv8.0. > FEAT_AdvSIMD is OPTIONAL from Armv8.0. But also: > All Armv8-A systems that support standard operating systems with rich application environments also provide hardware support for Advanced SIMD instructions. and > All Armv8-A systems that support standard operating systems with rich application environments provide hardware support for Advanced SIMD and floating-point instructions. All Armv9-A systems that support standard operating systems with rich application environments also provide hardware support for SVE2 instructions. It is a requirement of the ARM Procedure Call Standard for AArch64, see Procedure Call Standard for the Arm 64-bit Architecture So, both FEAT_FP and FEAT_AdvSIMD are optional for Armv9-A and Armv8-A. But both are mandated in cores for "rich operating systems", which basically means it's mandated by the OS. Also, Armv9-A on OS level mandates SVE2.

boredatoms 2mo ago

I cant see debian remaining on rv64gc later on when enough rva23 boards are purchasable

brucehoult 2mo ago
Why? It'll still run fine. Just like Debian still runs on original x86-64-v1 from 1999, not x86-64-v3 (needs AVX2,FMA, BMI1, BMI2, LZCNT) or even x86-64-v3 (needs AVX-512). Similarly, Debian for arm64 still requires only ARMv8.0-A from 2011 not even ARMv8.2-A (everything from A75/A55 to A78/N1/V1) let alone ARMv9-A (A710, A510, X2 and on). Why would they do in the RISC-V world what they totally haven't done in amd64 or arm64?
- camel-cdr 2mo ago
  No, debian requires ARMv8.0-A + FP + NEON, as those are optinal extensions (even optional in ARMv9.0-A)
  - brucehoult 2mo ago
    SVE2 is compulsory in ARMv9-A, but NEON is optional?
    - camel-cdr 2mo ago
      https://support.arm.com/documentation/109697/2026_06/Feature-descriptions/The-Armv9-0-architecture-extension https://support.arm.com/documentation/109697/2026_06/Feature... > In an Armv9.0 implementation, if FEAT_FP and FEAT_AdvSIMD are implemented, the following features are implemented: ... This implies they don't have to be implemented. https://support.arm.com/documentation/109697/2026_06/Feature-descriptions/The-Armv8-0-architecture-extension https://support.arm.com/documentation/109697/2026_06/Feature... > FEAT_FP is OPTIONAL from Armv8.0. > FEAT_AdvSIMD is OPTIONAL from Armv8.0. But also: > All Armv8-A systems that support standard operating systems with rich application environments also provide hardware support for Advanced SIMD instructions. and > All Armv8-A systems that support standard operating systems with rich application environments provide hardware support for Advanced SIMD and floating-point instructions. All Armv9-A systems that support standard operating systems with rich application environments also provide hardware support for SVE2 instructions. It is a requirement of the ARM Procedure Call Standard for AArch64, see Procedure Call Standard for the Arm 64-bit Architecture So, both FEAT_FP and FEAT_AdvSIMD are optional for Armv9-A and Armv8-A. But both are mandated in cores for "rich operating systems", which basically means it's mandated by the OS. Also, Armv9-A on OS level mandates SVE2.