diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build index b927eb58c8..adcee66115 100644 --- a/rust/qemu-api/meson.build +++ b/rust/qemu-api/meson.build @@ -16,6 +16,7 @@ _qemu_api_rs = static_library( [ 'src/lib.rs', 'src/bindings.rs', + 'src/bitops.rs', 'src/cell.rs', 'src/c_str.rs', 'src/definitions.rs', diff --git a/rust/qemu-api/src/bitops.rs b/rust/qemu-api/src/bitops.rs new file mode 100644 index 0000000000..023ec1a998 --- /dev/null +++ b/rust/qemu-api/src/bitops.rs @@ -0,0 +1,119 @@ +// Copyright (C) 2024 Intel Corporation. +// Author(s): Zhao Liu +// 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 + AddAssign + + BitAnd + BitAndAssign + + BitOr + BitOrAssign + + BitXor + BitXorAssign + + Copy + + Div + DivAssign + + Eq + + Mul + MulAssign + + Not + Ord + PartialOrd + + Rem + RemAssign + + Shl + ShlAssign + + Shl + ShlAssign + // add more as needed + Shr + ShrAssign + + Shr + ShrAssign // 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(self, start: u32, length: u32, + fieldval: U) -> Self + where Self: From + { + 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 0efbef4744..9e007e1635 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 dfaddbd062..a39e228bab 100644 --- a/rust/qemu-api/src/prelude.rs +++ b/rust/qemu-api/src/prelude.rs @@ -2,5 +2,7 @@ // Author(s): Paolo Bonzini // SPDX-License-Identifier: GPL-2.0-or-later +pub use crate::bitops::IntegerExt; + pub use crate::cell::BqlCell; pub use crate::cell::BqlRefCell;