refactor(domain): move irq tests to separate file, fix MemoryRegion import in platform

crates/domain/src/irq/mod.rs

@@ -0,0 +1,38 @@
+use types::id::{IrqId, ThreadId};
+
+use crate::error::KernelError;
+
+#[cfg(test)]
+#[path = "tests.rs"]
+mod tests;
+
+const MAX_IRQS: usize = 256;
+
+pub struct IrqRoutingTable {
+    owners: [Option<ThreadId>; MAX_IRQS],
+}
+
+impl IrqRoutingTable {
+    pub fn new() -> Self {
+        Self {
+            owners: [None; MAX_IRQS],
+        }
+    }
+
+    pub fn register(&mut self, irq: IrqId, thread: ThreadId) -> Result<(), KernelError> {
+        let idx = irq.raw() as usize;
+        if self.owners[idx].is_some() {
+            return Err(KernelError::IrqAlreadyOwned(irq));
+        }
+        self.owners[idx] = Some(thread);
+        Ok(())
+    }
+
+    pub fn unregister(&mut self, irq: IrqId) {
+        self.owners[irq.raw() as usize] = None;
+    }
+
+    pub fn owner(&self, irq: IrqId) -> Option<ThreadId> {
+        self.owners[irq.raw() as usize]
+    }
+}