1 files changed, 21 insertions, 0 deletions
diff --git a/riscv/arith.h b/riscv/arith.h
index 3b807e9..20b1504 100644
--- a/riscv/arith.h
+++ b/riscv/arith.h
@@ -7,6 +7,7 @@
 #include <cstdint>
 #include <climits>
 #include <cstddef>
+#include <type_traits>
 
 inline uint64_t mulhu(uint64_t a, uint64_t b)
 {
@@ -221,4 +222,24 @@ static inline uint64_t xperm(uint64_t rs1, uint64_t rs2, size_t sz_log2, size_t
   return r;
 }
 
+// Rotates right an unsigned integer by the given number of bits.
+template <typename T>
+static inline T rotate_right(T x, std::size_t shiftamt) {
+  static_assert(std::is_unsigned<T>::value);
+  static constexpr T mask = (8 * sizeof(T)) - 1;
+  const std::size_t rshift = shiftamt & mask;
+  const std::size_t lshift = (-rshift) & mask;
+  return (x << lshift) | (x >> rshift);
+}
+
+// Rotates right an unsigned integer by the given number of bits.
+template <typename T>
+static inline T rotate_left(T x, std::size_t shiftamt) {
+  static_assert(std::is_unsigned<T>::value);
+  static constexpr T mask = (8 * sizeof(T)) - 1;
+  const std::size_t lshift = shiftamt & mask;
+  const std::size_t rshift = (-lshift) & mask;
+  return (x << lshift) | (x >> rshift);
+}
+
 #endif