Add simple uart driver, more functionality etc etc etc

x86_drivers/src/idt.rs

@@ -0,0 +1,56 @@
+use crate::gdt::{DPL, GdtSelector};
+
+#[repr(C, packed)]
+pub struct InterruptTableDescriptor {
+    size: u16,
+    offset: u64,
+}
+
+#[repr(transparent)]
+pub struct IdtTableEntry {
+    inner: u128,
+}
+
+pub type ISR = extern "x86-interrupt" fn(InterruptStackFrame) -> ();
+
+#[repr(C)]
+pub struct InterruptStackFrame {
+    ip: usize,
+    cs: usize,
+    flags: usize,
+    sp: usize,
+    ss: usize,
+}
+
+#[repr(u8)]
+pub enum Gate {
+    Interrupt = 0b1110,
+    Trap = 0b1111,
+}
+
+impl IdtTableEntry {
+    pub fn new(isr: ISR, selector: GdtSelector, ist: u8, gate: Gate, priority: DPL) -> Self {
+        let mut inner = 0b0;
+        let offset = (isr as *const ()) as u64;
+
+        let bytes = (offset >> 32) as u32;
+        inner |= (bytes as u128) << 64;
+
+        let bytes = (offset as u32) >> 16;
+        inner |= (bytes as u128) << 48;
+
+        let bytes = offset as u16;
+        inner |= bytes as u128;
+
+        inner |= (selector.raw() as u128) << 16;
+
+        assert!(ist <= 0b111);
+
+        inner |= (ist as u128) << 32;
+        inner |= (gate as u128) << 40;
+        inner |= (priority as u128) << 45;
+        inner |= 1 << 47;
+
+        Self { inner }
+    }
+}