3 files changed, 122 insertions, 0 deletions
diff --git a/rust/qemu-api/src/bitops.rs b/rust/qemu-api/src/bitops.rs
new file mode 100644
index 0000000..023ec1a
--- /dev/null
+++ b/rust/qemu-api/src/bitops.rs
@@ -0,0 +1,119 @@
+// Copyright (C) 2024 Intel Corporation.
+// Author(s): Zhao Liu <zhai1.liu@intel.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! This module provides bit operation extensions to integer types.
+//! It is usually included via the `qemu_api` prelude.
+
+use std::ops::{
+    Add, AddAssign, BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Div, DivAssign,
+    Mul, MulAssign, Not, Rem, RemAssign, Shl, ShlAssign, Shr, ShrAssign,
+};
+
+/// Trait for extensions to integer types
+pub trait IntegerExt:
+    Add<Self, Output = Self> + AddAssign<Self> +
+    BitAnd<Self, Output = Self> + BitAndAssign<Self> +
+    BitOr<Self, Output = Self> + BitOrAssign<Self> +
+    BitXor<Self, Output = Self> + BitXorAssign<Self> +
+    Copy +
+    Div<Self, Output = Self> + DivAssign<Self> +
+    Eq +
+    Mul<Self, Output = Self> + MulAssign<Self> +
+    Not<Output = Self> + Ord + PartialOrd +
+    Rem<Self, Output = Self> + RemAssign<Self> +
+    Shl<Self, Output = Self> + ShlAssign<Self> +
+    Shl<u32, Output = Self> + ShlAssign<u32> + // add more as needed
+    Shr<Self, Output = Self> + ShrAssign<Self> +
+    Shr<u32, Output = Self> + ShrAssign<u32> // add more as needed
+{
+    const BITS: u32;
+    const MAX: Self;
+    const MIN: Self;
+    const ONE: Self;
+    const ZERO: Self;
+
+    #[inline]
+    #[must_use]
+    fn bit(start: u32) -> Self
+    {
+        debug_assert!(start < Self::BITS);
+
+        Self::ONE << start
+    }
+
+    #[inline]
+    #[must_use]
+    fn mask(start: u32, length: u32) -> Self
+    {
+        /* FIXME: Implement a more elegant check with error handling support? */
+        debug_assert!(start < Self::BITS && length > 0 && length <= Self::BITS - start);
+
+        (Self::MAX >> (Self::BITS - length)) << start
+    }
+
+    #[inline]
+    #[must_use]
+    fn deposit<U: IntegerExt>(self, start: u32, length: u32,
+                          fieldval: U) -> Self
+        where Self: From<U>
+    {
+        debug_assert!(length <= U::BITS);
+
+        let mask = Self::mask(start, length);
+        (self & !mask) | ((Self::from(fieldval) << start) & mask)
+    }
+
+    #[inline]
+    #[must_use]
+    fn extract(self, start: u32, length: u32) -> Self
+    {
+        let mask = Self::mask(start, length);
+        (self & mask) >> start
+    }
+}
+
+macro_rules! impl_num_ext {
+    ($type:ty) => {
+        impl IntegerExt for $type {
+            const BITS: u32 = <$type>::BITS;
+            const MAX: Self = <$type>::MAX;
+            const MIN: Self = <$type>::MIN;
+            const ONE: Self = 1;
+            const ZERO: Self = 0;
+        }
+    };
+}
+
+impl_num_ext!(u8);
+impl_num_ext!(u16);
+impl_num_ext!(u32);
+impl_num_ext!(u64);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_deposit() {
+        assert_eq!(15u32.deposit(8, 8, 1u32), 256 + 15);
+        assert_eq!(15u32.deposit(8, 1, 255u8), 256 + 15);
+    }
+
+    #[test]
+    fn test_extract() {
+        assert_eq!(15u32.extract(2, 4), 3);
+    }
+
+    #[test]
+    fn test_bit() {
+        assert_eq!(u8::bit(7), 128);
+        assert_eq!(u32::bit(16), 0x10000);
+    }
+
+    #[test]
+    fn test_mask() {
+        assert_eq!(u8::mask(7, 1), 128);
+        assert_eq!(u32::mask(8, 8), 0xff00);
+    }
+}
diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
index 0efbef4..9e007e1 100644
--- a/rust/qemu-api/src/lib.rs
+++ b/rust/qemu-api/src/lib.rs
@@ -12,6 +12,7 @@ pub mod bindings;
 #[rustfmt::skip]
 pub mod prelude;
 
+pub mod bitops;
 pub mod c_str;
 pub mod cell;
 pub mod definitions;
diff --git a/rust/qemu-api/src/prelude.rs b/rust/qemu-api/src/prelude.rs
index dfaddbd..a39e228 100644
--- a/rust/qemu-api/src/prelude.rs
+++ b/rust/qemu-api/src/prelude.rs
@@ -2,5 +2,7 @@
 // Author(s): Paolo Bonzini <pbonzini@redhat.com>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+pub use crate::bitops::IntegerExt;
+
 pub use crate::cell::BqlCell;
 pub use crate::cell::BqlRefCell;