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RISC-V: Add placeholder for the "B" extension

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The "B" extension is once abandoned (instead, it is ratified as a collection
of "Zb*" extensions).  However, it is later redefined and ratified as a
superset of "Zba", "Zbb" and "Zbs" extensions (but not "Zbc" carry-less
multiplication for limited benefits and implementation cost).

Although non-functional (because feature detection is not yet implemented),
it provides the foundation to implement this extension (along with
straightforward documentation showing subsets of "B").
This commit is contained in:
Tsukasa OI 2025-04-11 01:13:44 +00:00 • committed by Amanieu d'Antras
parent 68c54c19be
commit ed2d3ee924
1 changed files with 5 additions and 2 deletions
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7
library/stdarch/crates/std_detect/src/detect/arch/riscv.rs
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@ -32,10 +32,9 @@ features! {
/// * A: `"a"`
/// * Zaamo: `"zaamo"`
/// * Zalrsc: `"zalrsc"`
/// * Bit-Manipulation Extensions:
/// * B: `"b"`
/// * Zba: `"zba"`
/// * Zbb: `"zbb"`
/// * Zbc: `"zbc"`
/// * Zbs: `"zbs"`
/// * C: `"c"`
/// * D: `"d"`
@ -54,6 +53,7 @@ features! {
/// * Zdinx: `"zdinx"`
/// * Zhinx: `"zhinx"`
/// * Zhinxmin: `"zhinxmin"`
/// * Zbc: `"zbc"`
/// * Zbkb: `"zbkb"`
/// * Zbkc: `"zbkc"`
/// * Zbkx: `"zbkx"`
@ -159,6 +159,9 @@ features! {
@FEATURE: #[stable(feature = "riscv_ratified", since = "1.78.0")] c: "c";
/// "C" Extension for Compressed Instructions
@FEATURE: #[unstable(feature = "stdarch_riscv_feature_detection", issue = "111192")] b: "b";
without cfg check: true;
/// "B" Extension for Bit Manipulation
@FEATURE: #[stable(feature = "riscv_ratified", since = "1.78.0")] zba: "zba";
/// "Zba" Extension for Address Generation
@FEATURE: #[stable(feature = "riscv_ratified", since = "1.78.0")] zbb: "zbb";