@@ -22,133 +22,87 @@ features! {
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///
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/// [ISA manual]: https://riscv.org/specifications/ratified/
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///
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- /// # Platform-specific/agnostic Behavior and Availability
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- ///
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- /// Runtime detection depends on the platform-specific feature detection
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- /// facility and its availability per feature is
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- /// highly platform/version-specific.
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- ///
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- /// Still, a best-effort attempt is performed to enable subset/dependent
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- /// features if a superset feature is enabled regardless of the platform.
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- /// For instance, if the A extension (`"a"`) is enabled, its subsets (the
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- /// Zalrsc and Zaamo extensions; `"zalrsc"` and `"zaamo"`) are also enabled.
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- /// Likewise, if the F extension (`"f"`) is enabled, one of its dependencies
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- /// (the Zicsr extension `"zicsr"`) is also enabled.
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- ///
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/// # Unprivileged Specification
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///
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- /// The supported ratified RISC-V instruction sets are as follows (OS
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- /// columns denote runtime feature detection support with or without the
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- /// minimum supported version):
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- ///
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- /// | Literal | Base | Linux |
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- /// |:---------- |:------- |:---------- |
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- /// | `"rv32e"` | RV32E | No |
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- /// | `"rv32i"` | RV32I | Yes [^ima] |
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- /// | `"rv64i"` | RV64I | Yes [^ima] |
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- ///
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- /// | Literal | Extension | Linux |
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- /// |:--------------- |:----------- |:------------------ |
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- /// | `"a"` | A | Yes [^ima] |
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- /// | `"b"` | B | 6.5 |
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- /// | `"c"` | C | Yes |
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- /// | `"d"` | D | Yes |
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- /// | `"f"` | F | Yes |
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- /// | `"m"` | M | Yes [^ima] |
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- /// | `"q"` | Q | No |
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- /// | `"v"` | V | 6.5 |
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- /// | `"zaamo"` | Zaamo | No [^ima] [^dep] |
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- /// | `"zacas"` | Zacas | 6.8 |
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- /// | `"zalrsc"` | Zalrsc | No [^ima] [^dep] |
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- /// | `"zawrs"` | Zawrs | 6.11 |
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- /// | `"zba"` | Zba | 6.5 |
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- /// | `"zbb"` | Zbb | 6.5 |
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- /// | `"zbc"` | Zbc | 6.8 |
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- /// | `"zbkb"` | Zbkb | 6.8 |
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- /// | `"zbkc"` | Zbkc | 6.8 |
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- /// | `"zbkx"` | Zbkx | 6.8 |
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- /// | `"zbs"` | Zbs | 6.5 |
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- /// | `"zca"` | Zca | 6.11 [^dep] |
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- /// | `"zcb"` | Zcb | 6.11 [^dep] |
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- /// | `"zcd"` | Zcd | 6.11 [^dep] |
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- /// | `"zcf"` | Zcf | 6.11 [^dep] |
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- /// | `"zcmop"` | Zcmop | 6.11 |
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- /// | `"zdinx"` | Zdinx | No |
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- /// | `"zfa"` | Zfa | 6.8 |
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- /// | `"zfh"` | Zfh | 6.8 |
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- /// | `"zfhmin"` | Zfhmin | 6.8 |
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- /// | `"zfinx"` | Zfinx | No |
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- /// | `"zhinx"` | Zhinx | No |
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- /// | `"zhinxmin"` | Zhinxmin | No |
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- /// | `"zicboz"` | Zicboz | 6.7 |
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- /// | `"zicntr"` | Zicntr | No [^ima-cntr] [^cntr] |
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- /// | `"zicond"` | Zicond | 6.8 |
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- /// | `"zicsr"` | Zicsr | No [^ima] [^dep] |
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- /// | `"zifencei"` | Zifencei | No [^ima] |
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- /// | `"zihintntl"` | Zihintntl | 6.8 |
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- /// | `"zihintpause"` | Zihintpause | 6.10 |
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- /// | `"zihpm"` | Zihpm | No |
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- /// | `"zimop"` | Zimop | 6.11 |
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- /// | `"zk"` | Zk | No [^zkr] |
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- /// | `"zkn"` | Zkn | 6.8 |
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- /// | `"zknd"` | Zknd | 6.8 |
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- /// | `"zkne"` | Zkne | 6.8 |
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- /// | `"zknh"` | Zknh | 6.8 |
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- /// | `"zkr"` | Zkr | No [^zkr] |
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- /// | `"zks"` | Zks | 6.8 |
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- /// | `"zksed"` | Zksed | 6.8 |
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- /// | `"zksh"` | Zksh | 6.8 |
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- /// | `"zkt"` | Zkt | 6.8 |
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- /// | `"ztso"` | Ztso | 6.8 |
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- /// | `"zvbb"` | Zvbb | 6.8 |
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- /// | `"zvbc"` | Zvbc | 6.8 |
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- /// | `"zve32f"` | Zve32f | 6.11 [^dep] |
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- /// | `"zve32x"` | Zve32x | 6.11 [^dep] |
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- /// | `"zve64d"` | Zve64d | 6.11 [^dep] |
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- /// | `"zve64f"` | Zve64f | 6.11 [^dep] |
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- /// | `"zve64x"` | Zve64x | 6.11 [^dep] |
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- /// | `"zvfh"` | Zvfh | 6.8 |
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- /// | `"zvfhmin"` | Zvfhmin | 6.8 |
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- /// | `"zvkb"` | Zvkb | 6.8 |
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- /// | `"zvkg"` | Zvkg | 6.8 |
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- /// | `"zvkn"` | Zvkn | 6.8 |
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- /// | `"zvknc"` | Zvknc | 6.8 |
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- /// | `"zvkned"` | Zvkned | 6.8 |
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- /// | `"zvkng"` | Zvkng | 6.8 |
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- /// | `"zvknha"` | Zvknha | 6.8 |
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- /// | `"zvknhb"` | Zvknhb | 6.8 |
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- /// | `"zvks"` | Zvks | 6.8 |
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- /// | `"zvksc"` | Zvksc | 6.8 |
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- /// | `"zvksed"` | Zvksed | 6.8 |
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- /// | `"zvksg"` | Zvksg | 6.8 |
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- /// | `"zvksh"` | Zvksh | 6.8 |
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- /// | `"zvkt"` | Zvkt | 6.8 |
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- ///
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- /// [^ima]: Or enabled when the IMA base behavior is enabled on the Linux
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- /// kernel version 6.4 or later (for bases, the only matching one -- either
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- /// `"rv32i"` or `"rv64i"` -- is enabled).
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- ///
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- /// [^ima-cntr]: If the IMA base behavior is enabled on the Linux kernel
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- /// version 6.4 or later, the Zicntr extension should be also present.
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- /// However, it seems that Linux does not guarantee its existence.
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- ///
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- /// [^cntr]: Even if this extension is available, it does not necessarily
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- /// mean all performance counters are accessible.
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- /// For instance, the Linux kernel version 6.6 or later prohibits accesses
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- /// to performance counters other than `time` (wall-clock) by default.
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- /// Also beware that, even if performance counters like `cycle` and
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- /// `instret` are accessible, their value can be unreliable (e.g. returning
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- /// the constant value) under certain circumstances.
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- ///
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- /// [^dep]: Or enabled as a dependency of another extension (a superset)
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- /// even if runtime detection of this feature itself is not supported (as
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- /// long as the runtime detection of the superset is supported).
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+ /// The supported ratified RISC-V instruction sets are as follows:
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///
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- /// [^zkr]: Linux does not report existence of this extension even if
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- /// supported by the hardware mainly because the `seed` CSR is normally
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- /// inaccessible from the user mode.
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- /// For the Zk extension features except this CSR, check existence of both
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- /// `"zkn"` and `"zkt"` features instead.
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+ /// * RV32E: `"rv32e"`
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+ /// * RV32I: `"rv32i"`
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+ /// * RV64I: `"rv64i"`
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+ /// * A: `"a"`
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+ /// * Zaamo: `"zaamo"`
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+ /// * Zalrsc: `"zalrsc"`
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+ /// * B: `"b"`
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+ /// * Zba: `"zba"`
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+ /// * Zbb: `"zbb"`
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+ /// * Zbs: `"zbs"`
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+ /// * C: `"c"`
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+ /// * Zca: `"zca"`
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+ /// * Zcd: `"zcd"` (if D is enabled)
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+ /// * Zcf: `"zcf"` (if F is enabled on RV32)
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+ /// * D: `"d"`
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+ /// * F: `"f"`
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+ /// * M: `"m"`
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+ /// * Q: `"q"`
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+ /// * V: `"v"`
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+ /// * Zve32x: `"zve32x"`
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+ /// * Zve32f: `"zve32f"`
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+ /// * Zve64x: `"zve64x"`
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+ /// * Zve64f: `"zve64f"`
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+ /// * Zve64d: `"zve64d"`
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+ /// * Zicboz: `"zicboz"`
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+ /// * Zicntr: `"zicntr"`
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+ /// * Zicond: `"zicond"`
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+ /// * Zicsr: `"zicsr"`
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+ /// * Zifencei: `"zifencei"`
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+ /// * Zihintntl: `"zihintntl"`
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+ /// * Zihintpause: `"zihintpause"`
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+ /// * Zihpm: `"zihpm"`
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+ /// * Zimop: `"zimop"`
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+ /// * Zacas: `"zacas"`
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+ /// * Zawrs: `"zawrs"`
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+ /// * Zfa: `"zfa"`
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+ /// * Zfh: `"zfh"`
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+ /// * Zfhmin: `"zfhmin"`
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+ /// * Zfinx: `"zfinx"`
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+ /// * Zdinx: `"zdinx"`
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+ /// * Zhinx: `"zhinx"`
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+ /// * Zhinxmin: `"zhinxmin"`
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+ /// * Zcb: `"zcb"`
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+ /// * Zcmop: `"zcmop"`
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+ /// * Zbc: `"zbc"`
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+ /// * Zbkb: `"zbkb"`
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+ /// * Zbkc: `"zbkc"`
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+ /// * Zbkx: `"zbkx"`
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+ /// * Zk: `"zk"`
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+ /// * Zkn: `"zkn"`
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+ /// * Zknd: `"zknd"`
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+ /// * Zkne: `"zkne"`
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+ /// * Zknh: `"zknh"`
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+ /// * Zkr: `"zkr"`
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+ /// * Zks: `"zks"`
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+ /// * Zksed: `"zksed"`
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+ /// * Zksh: `"zksh"`
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+ /// * Zkt: `"zkt"`
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+ /// * Zvbb: `"zvbb"`
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+ /// * Zvbc: `"zvbc"`
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+ /// * Zvfh: `"zvfh"`
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+ /// * Zvfhmin: `"zvfhmin"`
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+ /// * Zvkb: `"zvkb"`
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+ /// * Zvkg: `"zvkg"`
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+ /// * Zvkn: `"zvkn"`
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+ /// * Zvkned: `"zvkned"`
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+ /// * Zvknha: `"zvknha"`
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+ /// * Zvknhb: `"zvknhb"`
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+ /// * Zvknc: `"zvknc"`
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+ /// * Zvkng: `"zvkng"`
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+ /// * Zvks: `"zvks"`
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+ /// * Zvksed: `"zvksed"`
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+ /// * Zvksh: `"zvksh"`
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+ /// * Zvksc: `"zvksc"`
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+ /// * Zvksg: `"zvksg"`
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+ /// * Zvkt: `"zvkt"`
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+ /// * Ztso: `"ztso"`
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///
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/// There's also bases and extensions marked as standard instruction set,
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/// but they are in frozen or draft state. These instruction sets are also
@@ -168,9 +122,7 @@ features! {
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/// corresponding unaligned memory access is reasonably fast.
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///
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/// * `"unaligned-scalar-mem"`
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- /// * Runtime detection requires Linux kernel version 6.4 or later.
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/// * `"unaligned-vector-mem"`
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- /// * Runtime detection requires Linux kernel version 6.13 or later.
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#[ stable( feature = "riscv_ratified" , since = "1.78.0" ) ]
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@FEATURE : #[ unstable( feature = "stdarch_riscv_feature_detection" , issue = "111192" ) ] rv32i: "rv32i" ;
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