From 08484b5e7a93181c49f4ce8654270dfa47dd6ebb Mon Sep 17 00:00:00 2001 From: Tsukasa OI Date: Wed, 30 Apr 2025 05:42:42 +0000 Subject: std_detect: RISC-V platform guide documentation (non-table part) This is a partial revert of a revert, making the commit e907456b2e10622ccd854a3bba8d02ce170b5dbb come around again for non-table part. --- .../stdarch/crates/std_detect/src/detect/arch/riscv.rs | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'library/stdarch/crates/std_detect/src/detect') diff --git a/library/stdarch/crates/std_detect/src/detect/arch/riscv.rs b/library/stdarch/crates/std_detect/src/detect/arch/riscv.rs index 63790537f85..c85ba04861e 100644 --- a/library/stdarch/crates/std_detect/src/detect/arch/riscv.rs +++ b/library/stdarch/crates/std_detect/src/detect/arch/riscv.rs @@ -22,6 +22,19 @@ features! { /// /// [ISA manual]: https://riscv.org/specifications/ratified/ /// + /// # Platform-specific/agnostic Behavior and Availability + /// + /// Runtime detection depends on the platform-specific feature detection + /// facility and its availability per feature is + /// highly platform/version-specific. + /// + /// Still, a best-effort attempt is performed to enable subset/dependent + /// features if a superset feature is enabled regardless of the platform. + /// For instance, if the A extension (`"a"`) is enabled, its subsets (the + /// Zalrsc and Zaamo extensions; `"zalrsc"` and `"zaamo"`) are also enabled. + /// Likewise, if the F extension (`"f"`) is enabled, one of its dependencies + /// (the Zicsr extension `"zicsr"`) is also enabled. + /// /// # Unprivileged Specification /// /// The supported ratified RISC-V instruction sets are as follows: @@ -122,7 +135,9 @@ features! { /// corresponding unaligned memory access is reasonably fast. /// /// * `"unaligned-scalar-mem"` + /// * Runtime detection requires Linux kernel version 6.4 or later. /// * `"unaligned-vector-mem"` + /// * Runtime detection requires Linux kernel version 6.13 or later. #[stable(feature = "riscv_ratified", since = "1.78.0")] @FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] rv32i: "rv32i"; -- cgit 1.4.1-3-g733a5