# address.rs - source
Source of the Rust file `src/mm/address.rs`.
Keywords: rust, rustlang, rust-lang

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    use super::PageTableEntry;
    use crate::config::{PAGE_SIZE, PAGE_SIZE_BITS};
    use core::fmt::{self, Debug, Formatter};

    const PA_WIDTH_SV39: usize = 56;
    const VA_WIDTH_SV39: usize = 39;
    const PPN_WIDTH_SV39: usize = PA_WIDTH_SV39 - PAGE_SIZE_BITS;
    const VPN_WIDTH_SV39: usize = VA_WIDTH_SV39 - PAGE_SIZE_BITS;

    /// Definitions
    #[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
    pub struct PhysAddr(pub usize);

    #[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
    pub struct VirtAddr(pub usize);

    #[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
    pub struct PhysPageNum(pub usize);

    #[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
    pub struct VirtPageNum(pub usize);

    /// Debugging

    impl Debug for VirtAddr {
        fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
            f.write_fmt(format_args!("VA:{:#x}", self.0))
        }
    }
    impl Debug for VirtPageNum {
        fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
            f.write_fmt(format_args!("VPN:{:#x}", self.0))
        }
    }
    impl Debug for PhysAddr {
        fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
            f.write_fmt(format_args!("PA:{:#x}", self.0))
        }
    }
    impl Debug for PhysPageNum {
        fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
            f.write_fmt(format_args!("PPN:{:#x}", self.0))
        }
    }

    /// T: {PhysAddr, VirtAddr, PhysPageNum, VirtPageNum}
    /// T -> usize: T.0
    /// usize -> T: usize.into()

    impl From<usize> for PhysAddr {
        fn from(v: usize) -> Self {
            Self(v & ((1 << PA_WIDTH_SV39) - 1))
        }
    }
    impl From<usize> for PhysPageNum {
        fn from(v: usize) -> Self {
            Self(v & ((1 << PPN_WIDTH_SV39) - 1))
        }
    }
    impl From<usize> for VirtAddr {
        fn from(v: usize) -> Self {
            Self(v & ((1 << VA_WIDTH_SV39) - 1))
        }
    }
    impl From<usize> for VirtPageNum {
        fn from(v: usize) -> Self {
            Self(v & ((1 << VPN_WIDTH_SV39) - 1))
        }
    }
    impl From<PhysAddr> for usize {
        fn from(v: PhysAddr) -> Self {
            v.0
        }
    }
    impl From<PhysPageNum> for usize {
        fn from(v: PhysPageNum) -> Self {
            v.0
        }
    }
    impl From<VirtAddr> for usize {
        fn from(v: VirtAddr) -> Self {
            v.0
        }
    }
    impl From<VirtPageNum> for usize {
        fn from(v: VirtPageNum) -> Self {
            v.0
        }
    }

    impl VirtAddr {
        pub fn floor(&self) -> VirtPageNum {
            VirtPageNum(self.0 / PAGE_SIZE)
        }
        pub fn ceil(&self) -> VirtPageNum {
            VirtPageNum((self.0 - 1 + PAGE_SIZE) / PAGE_SIZE)
        }
        pub fn page_offset(&self) -> usize {
            self.0 & (PAGE_SIZE - 1)
        }
        pub fn aligned(&self) -> bool {
            self.page_offset() == 0
        }
    }
    impl From<VirtAddr> for VirtPageNum {
        fn from(v: VirtAddr) -> Self {
            assert_eq!(v.page_offset(), 0);
            v.floor()
        }
    }
    impl From<VirtPageNum> for VirtAddr {
        fn from(v: VirtPageNum) -> Self {
            Self(v.0 << PAGE_SIZE_BITS)
        }
    }
    impl PhysAddr {
        pub fn floor(&self) -> PhysPageNum {
            PhysPageNum(self.0 / PAGE_SIZE)
        }
        pub fn ceil(&self) -> PhysPageNum {
            PhysPageNum((self.0 - 1 + PAGE_SIZE) / PAGE_SIZE)
        }
        pub fn page_offset(&self) -> usize {
            self.0 & (PAGE_SIZE - 1)
        }
        pub fn aligned(&self) -> bool {
            self.page_offset() == 0
        }
    }
    impl From<PhysAddr> for PhysPageNum {
        fn from(v: PhysAddr) -> Self {
            assert_eq!(v.page_offset(), 0);
            v.floor()
        }
    }
    impl From<PhysPageNum> for PhysAddr {
        fn from(v: PhysPageNum) -> Self {
            Self(v.0 << PAGE_SIZE_BITS)
        }
    }

    impl VirtPageNum {
        pub fn indexes(&self) -> [usize; 3] {
            let mut vpn = self.0;
            let mut idx = [0usize; 3];
            for i in (0..3).rev() {
                idx[i] = vpn & 511;
                vpn >>= 9;
            }
            idx
        }
    }

    impl PhysAddr {
        pub fn get_mut<T>(&self) -> &'static mut T {
            unsafe { (self.0 as *mut T).as_mut().unwrap() }
        }
    }
    impl PhysPageNum {
        pub fn get_pte_array(&self) -> &'static mut [PageTableEntry] {
            let pa: PhysAddr = (*self).into();
            unsafe { core::slice::from_raw_parts_mut(pa.0 as *mut PageTableEntry, 512) }
        }
        pub fn get_bytes_array(&self) -> &'static mut [u8] {
            let pa: PhysAddr = (*self).into();
            unsafe { core::slice::from_raw_parts_mut(pa.0 as *mut u8, 4096) }
        }
        pub fn get_mut<T>(&self) -> &'static mut T {
            let pa: PhysAddr = (*self).into();
            pa.get_mut()
        }
    }

    pub trait StepByOne {
        fn step(&mut self);
    }
    impl StepByOne for VirtPageNum {
        fn step(&mut self) {
            self.0 += 1;
        }
    }

    #[derive(Copy, Clone)]
    pub struct SimpleRange<T>
    where
        T: StepByOne + Copy + PartialEq + PartialOrd + Debug,
    {
        l: T,
        r: T,
    }
    impl<T> SimpleRange<T>
    where
        T: StepByOne + Copy + PartialEq + PartialOrd + Debug,
    {
        pub fn new(start: T, end: T) -> Self {
            assert!(start <= end, "start {:?} > end {:?}!", start, end);
            Self { l: start, r: end }
        }
        pub fn get_start(&self) -> T {
            self.l
        }
        pub fn get_end(&self) -> T {
            self.r
        }
    }
    impl<T> IntoIterator for SimpleRange<T>
    where
        T: StepByOne + Copy + PartialEq + PartialOrd + Debug,
    {
        type Item = T;
        type IntoIter = SimpleRangeIterator<T>;
        fn into_iter(self) -> Self::IntoIter {
            SimpleRangeIterator::new(self.l, self.r)
        }
    }
    pub struct SimpleRangeIterator<T>
    where
        T: StepByOne + Copy + PartialEq + PartialOrd + Debug,
    {
        current: T,
        end: T,
    }
    impl<T> SimpleRangeIterator<T>
    where
        T: StepByOne + Copy + PartialEq + PartialOrd + Debug,
    {
        pub fn new(l: T, r: T) -> Self {
            Self { current: l, end: r }
        }
    }
    impl<T> Iterator for SimpleRangeIterator<T>
    where
        T: StepByOne + Copy + PartialEq + PartialOrd + Debug,
    {
        type Item = T;
        fn next(&mut self) -> Option<Self::Item> {
            if self.current == self.end {
                None
            } else {
                let t = self.current;
                self.current.step();
                Some(t)
            }
        }
    }
    pub type VPNRange = SimpleRange<VirtPageNum>;