test: add unit test for miselect

Adds a basic unit test for the `miselect` CSR.

Author: 0xllx0

riscv/CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Added
+
+- Add `miselect` CSR
+
 ## [v0.15.0] - 2025-09-08
 
 ### Added

riscv/src/register/miselect.rs

@@ -45,3 +45,20 @@ read_write_csr_field! {
     /// and the relevant `mireg*` value.
     value: [0:62],
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        (0..=usize::BITS)
+            .map(|r| ((1u128 << r) - 1) as usize)
+            .for_each(|bits| {
+                let mut miselect = Miselect::from_bits(bits);
+
+                test_csr_field!(miselect, is_custom);
+                test_csr_field!(miselect, value: [0, usize::BITS - 2], 0);
+            });
+    }
+}