use core::{ffi::c_void, ops::Range, ptr::addr_of};

pub mod physical_memory_free_list;

/// The number of bits in the offset in a page.
pub const PAGE_SIZE_BITS: usize = 12;

/// The size of a page, in bytes.
pub const PAGE_SIZE: usize = 1 << PAGE_SIZE_BITS;

/// Returns the physical address range the kernel is in.
pub fn kernel_boundaries() -> Range<usize> {
    extern "C" {
        static kernel_start: c_void;
        static kernel_end: c_void;
    }

    // SAFETY: We only use these as addresses, we never dereference them.
    let (kernel_start_addr, kernel_end_addr) =
        unsafe { (addr_of!(kernel_start), addr_of!(kernel_end)) };

    kernel_start_addr as usize..kernel_end_addr as usize
}