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  1. JDK
  2. JDK-8283865

riscv: Break down -XX:+UseRVB into seperate options for each bitmanip extension

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Details

    • Enhancement
    • Status: Resolved
    • P4
    • Resolution: Fixed
    • 19
    • 19
    • hotspot
    • None
    • b17
    • riscv
    • linux

    Backports

      Description

        Currently openjdk riscv supports RISC-V bitmanip extension as a bundle while spec provides four individual extensions: Zb[abcs][1].

        According to the spec, we need to break down `UseRVB` into two individual options `UseZba` and `UseZbb` to enable or disable Zba and Zbb respectively (openjdk riscv only supports Zba and Zbb for now).

        Since multi-letter extensions representation in the ISA bitmap is still not determined[2][3], availability for those extensions could not be queried from HWCAP. Feature detection of Zba and Zbb was removed temporarily.

        [1]: https://github.com/riscv/riscv-bitmanip/releases/download/1.0.0/bitmanip-1.0.0-38-g865e7a7.pdf
        [2]: http://lists.infradead.org/pipermail/linux-riscv/2021-November/010250.html
        [3]: http://lists.infradead.org/pipermail/linux-riscv/2021-November/010252.html

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                fjiang Feilong Jiang
                fjiang Feilong Jiang
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                  Created:
                  Updated:
                  Resolved: