1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142

use int::{Int, LargeInt};

trait Ashl: Int + LargeInt {
    /// Returns `a << b`, requires `b < Self::BITS`
    fn ashl(self, offset: u32) -> Self
    where
        Self: LargeInt<HighHalf = <Self as LargeInt>::LowHalf>,
    {
        let half_bits = Self::BITS / 2;
        if offset & half_bits != 0 {
            Self::from_parts(Int::ZERO, self.low() << (offset - half_bits))
        } else if offset == 0 {
            self
        } else {
            Self::from_parts(
                self.low() << offset,
                (self.high() << offset) | (self.low() >> (half_bits - offset)),
            )
        }
    }
}

impl Ashl for u64 {}
impl Ashl for u128 {}

trait Ashr: Int + LargeInt {
    /// Returns arithmetic `a >> b`, requires `b < Self::BITS`
    fn ashr(self, offset: u32) -> Self
    where
        Self: LargeInt<LowHalf = <<Self as LargeInt>::HighHalf as Int>::UnsignedInt>,
    {
        let half_bits = Self::BITS / 2;
        if offset & half_bits != 0 {
            Self::from_parts(
                (self.high() >> (offset - half_bits)).unsigned(),
                self.high() >> (half_bits - 1),
            )
        } else if offset == 0 {
            self
        } else {
            let high_unsigned = self.high().unsigned();
            Self::from_parts(
                (high_unsigned << (half_bits - offset)) | (self.low() >> offset),
                self.high() >> offset,
            )
        }
    }
}

impl Ashr for i64 {}
impl Ashr for i128 {}

trait Lshr: Int + LargeInt {
    /// Returns logical `a >> b`, requires `b < Self::BITS`
    fn lshr(self, offset: u32) -> Self
    where
        Self: LargeInt<HighHalf = <Self as LargeInt>::LowHalf>,
    {
        let half_bits = Self::BITS / 2;
        if offset & half_bits != 0 {
            Self::from_parts(self.high() >> (offset - half_bits), Int::ZERO)
        } else if offset == 0 {
            self
        } else {
            Self::from_parts(
                (self.high() << (half_bits - offset)) | (self.low() >> offset),
                self.high() >> offset,
            )
        }
    }
}

impl Lshr for u64 {}
impl Lshr for u128 {}

intrinsics! {
    #[maybe_use_optimized_c_shim]
    #[arm_aeabi_alias = __aeabi_llsl]
    pub extern "C" fn __ashldi3(a: u64, b: u32) -> u64 {
        a.ashl(b)
    }

    pub extern "C" fn __ashlti3(a: u128, b: u32) -> u128 {
        a.ashl(b)
    }

    #[maybe_use_optimized_c_shim]
    #[arm_aeabi_alias = __aeabi_lasr]
    pub extern "C" fn __ashrdi3(a: i64, b: u32) -> i64 {
        a.ashr(b)
    }

    pub extern "C" fn __ashrti3(a: i128, b: u32) -> i128 {
        a.ashr(b)
    }

    #[maybe_use_optimized_c_shim]
    #[arm_aeabi_alias = __aeabi_llsr]
    pub extern "C" fn __lshrdi3(a: u64, b: u32) -> u64 {
        a.lshr(b)
    }

    pub extern "C" fn __lshrti3(a: u128, b: u32) -> u128 {
        a.lshr(b)
    }
}

u128_lang_items! {
    #[lang = "i128_shl"]
    pub fn rust_i128_shl(a: i128, b: u32) -> i128 {
        __ashlti3(a as _, b) as _
    }
    #[lang = "i128_shlo"]
    pub fn rust_i128_shlo(a: i128, b: u128) -> (i128, bool) {
        (rust_i128_shl(a, b as _), b >= 128)
    }
    #[lang = "u128_shl"]
    pub fn rust_u128_shl(a: u128, b: u32) -> u128 {
        __ashlti3(a, b)
    }
    #[lang = "u128_shlo"]
    pub fn rust_u128_shlo(a: u128, b: u128) -> (u128, bool) {
        (rust_u128_shl(a, b as _), b >= 128)
    }

    #[lang = "i128_shr"]
    pub fn rust_i128_shr(a: i128, b: u32) -> i128 {
        __ashrti3(a, b)
    }
    #[lang = "i128_shro"]
    pub fn rust_i128_shro(a: i128, b: u128) -> (i128, bool) {
        (rust_i128_shr(a, b as _), b >= 128)
    }
    #[lang = "u128_shr"]
    pub fn rust_u128_shr(a: u128, b: u32) -> u128 {
        __lshrti3(a, b)
    }
    #[lang = "u128_shro"]
    pub fn rust_u128_shro(a: u128, b: u128) -> (u128, bool) {
        (rust_u128_shr(a, b as _), b >= 128)
    }
}