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 } 119