| 1 | // Copyright (C) 2024 Intel Corporation. |
| 2 | // Author(s): Zhao Liu <zhao1.liu@intel.com> |
| 3 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 4 | |
| 5 | //! This module provides bit operation extensions to integer types. |
| 6 | |
| 7 | use std::ops::{ |
| 8 | Add, AddAssign, BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Div, DivAssign, |
| 9 | Mul, MulAssign, Not, Rem, RemAssign, Shl, ShlAssign, Shr, ShrAssign, |
| 10 | }; |
| 11 | |
| 12 | /// Trait for extensions to integer types |
| 13 | pub trait IntegerExt: |
| 14 | Add<Self, Output = Self> + AddAssign<Self> + |
| 15 | BitAnd<Self, Output = Self> + BitAndAssign<Self> + |
| 16 | BitOr<Self, Output = Self> + BitOrAssign<Self> + |
| 17 | BitXor<Self, Output = Self> + BitXorAssign<Self> + |
| 18 | Copy + |
| 19 | Div<Self, Output = Self> + DivAssign<Self> + |
| 20 | Eq + |
| 21 | Mul<Self, Output = Self> + MulAssign<Self> + |
| 22 | Not<Output = Self> + Ord + PartialOrd + |
| 23 | Rem<Self, Output = Self> + RemAssign<Self> + |
| 24 | Shl<Self, Output = Self> + ShlAssign<Self> + |
| 25 | Shl<u32, Output = Self> + ShlAssign<u32> + // add more as needed |
| 26 | Shr<Self, Output = Self> + ShrAssign<Self> + |
| 27 | Shr<u32, Output = Self> + ShrAssign<u32> // add more as needed |
| 28 | { |
| 29 | const BITS: u32; |
| 30 | const MAX: Self; |
| 31 | const MIN: Self; |
| 32 | const ONE: Self; |
| 33 | const ZERO: Self; |
| 34 | |
| 35 | #[inline] |
| 36 | #[must_use] |
| 37 | fn bit(start: u32) -> Self |
| 38 | { |
| 39 | debug_assert!(start < Self::BITS); |
| 40 | |
| 41 | Self::ONE << start |
| 42 | } |
| 43 | |
| 44 | #[inline] |
| 45 | #[must_use] |
| 46 | fn mask(start: u32, length: u32) -> Self |
| 47 | { |
| 48 | /* FIXME: Implement a more elegant check with error handling support? */ |
| 49 | debug_assert!(start < Self::BITS && length > 0 && length <= Self::BITS - start); |
| 50 | |
| 51 | (Self::MAX >> (Self::BITS - length)) << start |
| 52 | } |
| 53 | |
| 54 | #[inline] |
| 55 | #[must_use] |
| 56 | fn deposit<U: IntegerExt>(self, start: u32, length: u32, |
| 57 | fieldval: U) -> Self |
| 58 | where Self: From<U> |
| 59 | { |
| 60 | debug_assert!(length <= U::BITS); |
| 61 | |
| 62 | let mask = Self::mask(start, length); |
| 63 | (self & !mask) | ((Self::from(fieldval) << start) & mask) |
| 64 | } |
| 65 | |
| 66 | #[inline] |
| 67 | #[must_use] |
| 68 | fn extract(self, start: u32, length: u32) -> Self |
| 69 | { |
| 70 | let mask = Self::mask(start, length); |
| 71 | (self & mask) >> start |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | macro_rules! impl_num_ext { |
| 76 | ($type:ty) => { |
| 77 | impl IntegerExt for $type { |
| 78 | const BITS: u32 = <$type>::BITS; |
| 79 | const MAX: Self = <$type>::MAX; |
| 80 | const MIN: Self = <$type>::MIN; |
| 81 | const ONE: Self = 1; |
| 82 | const ZERO: Self = 0; |
| 83 | } |
| 84 | }; |
| 85 | } |
| 86 | |
| 87 | impl_num_ext!(u8); |
| 88 | impl_num_ext!(u16); |
| 89 | impl_num_ext!(u32); |
| 90 | impl_num_ext!(u64); |
| 91 | |
| 92 | #[cfg(test)] |
| 93 | mod tests { |
| 94 | use super::*; |
| 95 | |
| 96 | #[test] |
| 97 | fn test_deposit() { |
| 98 | assert_eq!(15u32.deposit(8, 8, 1u32), 256 + 15); |
| 99 | assert_eq!(15u32.deposit(8, 1, 255u8), 256 + 15); |
| 100 | } |
| 101 | |
| 102 | #[test] |
| 103 | fn test_extract() { |
| 104 | assert_eq!(15u32.extract(2, 4), 3); |
| 105 | } |
| 106 | |
| 107 | #[test] |
| 108 | fn test_bit() { |
| 109 | assert_eq!(u8::bit(7), 128); |
| 110 | assert_eq!(u32::bit(16), 0x10000); |
| 111 | } |
| 112 | |
| 113 | #[test] |
| 114 | fn test_mask() { |
| 115 | assert_eq!(u8::mask(7, 1), 128); |
| 116 | assert_eq!(u32::mask(8, 8), 0xff00); |
| 117 | } |
| 118 | } |