- made improvements to memory code (refactored)

- started on improvements to the page frame allocator. it should be able to provide a usable page for any given virtual memory address requested.

kernel/src/arch/x86_64/memory/mod.rs

@@ -1,14 +1,20 @@
 pub mod allocation;
-pub mod memory_map;
+pub mod mapping;
+pub mod units;
 
-// use lib_alloc::allocator::FoundryAllocator;
-use limine::{memory_map::EntryType, response::MemoryMapResponse};
 use spin::{Mutex, Once};
 use x86_64::{
-    PhysAddr, VirtAddr,
-    registers::control::Cr3,
-    structures::paging::{FrameAllocator, OffsetPageTable, PageTable, PhysFrame, Size4KiB},
+    registers::control::Cr3, structures::paging::{FrameAllocator, OffsetPageTable, PageTable}
+    ,
+    VirtAddr,
 };
+use allocation::page_alloc::FoundryOSFrameAllocator;
+use units::MemoryUnits::*;
+
+pub const STACK_VIRTUAL_SPACE: usize = 0x5555_5555_0000; // start address of the memory space where we store allocated stacks
+pub const HEAP_VIRTUAL_SPACE: usize = 0x4444_4444_0000; // start address of heap allocated memory
+pub const HEAP_SIZE: usize = MiB(1).to_bytes();
+
 
 pub static FRAME_ALLOCATOR: Once<Mutex<FoundryOSFrameAllocator>> = Once::new();
 pub static OFFSET_PAGE_TABLE: Once<Mutex<OffsetPageTable>> = Once::new();
@@ -53,56 +59,3 @@ pub fn init_page_table(physical_memory_offset: VirtAddr) {
     }
 }
 
-pub struct FoundryOSFrameAllocator {
-    memory_map: &'static MemoryMapResponse,
-    next: usize,
-}
-
-impl FoundryOSFrameAllocator {
-    /// Creates a new `FoundryOSFrameAllocator` from a memory map.
-    ///
-    /// This function takes a reference to a `MemoryMapResponse` and initializes a
-    /// `FoundryOSFrameAllocator` with it. The `next` field is set to 0, indicating that
-    /// the first frame to be allocated is the first frame in the memory map.
-    pub unsafe fn init(memory_map: &'static MemoryMapResponse) { unsafe {
-        FRAME_ALLOCATOR.call_once(|| Mutex::new(Self {
-            memory_map,
-            next: 0,
-        }));
-    }}
-
-    pub fn count_usable_frames(&self) -> u32 {
-        self.usable_frames().count() as u32
-    }
-
-    /// An iterator over all usable frames in the memory map.
-    ///
-    /// Yields one `PhysFrame` for each available 4KiB frame in the memory map.
-    ///
-    /// This function is used to allocate frames for the pagemap.
-    fn usable_frames(&self) -> impl Iterator<Item = PhysFrame> + use<> {
-        let regions = self.memory_map.entries().iter();
-        let usable_regions = regions.filter(|region| region.entry_type == EntryType::USABLE);
-        let addr_ranges = usable_regions.map(|region| region.base..region.base + region.length);
-        let frame_addresses = addr_ranges.flat_map(|r| r.step_by(4096));
-        frame_addresses.map(|addr| PhysFrame::from_start_address(PhysAddr::new(addr)).unwrap())
-    }
-}
-
-unsafe impl FrameAllocator<Size4KiB> for FoundryOSFrameAllocator {
-    /// Allocates a frame from the list of usable frames.
-    ///
-    /// This function returns the next available `PhysFrame` from the memory map,
-    /// if one exists. Once a frame is allocated, the internal counter is incremented
-    /// to point to the next frame for future allocations.
-    ///
-    /// # Returns
-    ///
-    /// - `Some(PhysFrame)`: If a usable frame is available.
-    /// - `None`: If there are no more usable frames to allocate.
-    fn allocate_frame(&mut self) -> Option<PhysFrame> {
-        let frame = self.usable_frames().nth(self.next);
-        self.next += 1;
-        frame
-    }
-}