1 files changed, 39 insertions, 5 deletions
diff --git a/src/shared/dtables.rs b/src/shared/dtables.rs
index d2e3413..c5337fb 100644
--- a/src/shared/dtables.rs
+++ b/src/shared/dtables.rs
@@ -1,27 +1,61 @@
 //! Functions and data-structures to load descriptor tables.
 
+use core::mem::size_of;
+
+use current::irq::IdtEntry;
+use shared::segmentation::SegmentDescriptor;
+
 /// A struct describing a pointer to a descriptor table (GDT / IDT).
 /// This is in a format suitable for giving to 'lgdt' or 'lidt'.
 #[derive(Debug)]
 #[repr(C, packed)]
-pub struct DescriptorTablePointer {
+pub struct DescriptorTablePointer<Entry> {
     /// Size of the DT.
     pub limit: u16,
     /// Pointer to the memory region containing the DT.
-    pub base: u64,
+    pub base: *const Entry,
 }
 
+impl<T> DescriptorTablePointer<T> {
+    fn new(slice: &[T]) -> Self {
+        let len = slice.len() * size_of::<T>();
+        assert!(len < 0x10000);
+        DescriptorTablePointer {
+            base: slice.as_ptr(),
+            limit: len as u16,
+        }
+    }
+}
+
+impl DescriptorTablePointer<SegmentDescriptor> {
+    pub fn new_gdtp(gdt: &[SegmentDescriptor]) -> Self {
+        let mut p = Self::new(gdt);
+        p.limit -= 1;
+        p
+    }
+    pub fn new_ldtp(ldt: &[SegmentDescriptor]) -> Self {
+        Self::new(ldt)
+    }
+}
+
+impl DescriptorTablePointer<IdtEntry> {
+    pub fn new_idtp(idt: &[IdtEntry]) -> Self {
+        Self::new(idt)
+    }
+}
+
+
 /// Load GDT table.
-pub unsafe fn lgdt(gdt: &DescriptorTablePointer) {
+pub unsafe fn lgdt(gdt: &DescriptorTablePointer<SegmentDescriptor>) {
     asm!("lgdt ($0)" :: "r" (gdt) : "memory");
 }
 
 /// Load LDT table.
-pub unsafe fn lldt(ldt: &DescriptorTablePointer) {
+pub unsafe fn lldt(ldt: &DescriptorTablePointer<SegmentDescriptor>) {
     asm!("lldt ($0)" :: "r" (ldt) : "memory");
 }
 
 /// Load IDT table.
-pub unsafe fn lidt(idt: &DescriptorTablePointer) {
+pub unsafe fn lidt(idt: &DescriptorTablePointer<IdtEntry>) {
     asm!("lidt ($0)" :: "r" (idt) : "memory");
 }