feat(pl/pc): add APIC timer support

src/ex/init.zig

@@ -1,8 +1,13 @@
 const std = @import("std");
-const b = @import("root");
-const pl = b.pl;
-const ke = b.ke;
-const mm = b.mm;
+const r = @import("root");
+const pl = r.pl;
+const ke = r.ke;
+const mm = r.mm;
+const amd64 = @import("arch");
+
+fn callback(_: ?*anyopaque) void {
+    std.log.info("Timer callback called", .{});
+}
 
 pub fn init(boot_info: *pl.BootInfo) void {
     mm.init(boot_info);
@@ -10,6 +15,13 @@ pub fn init(boot_info: *pl.BootInfo) void {
     pl.late_init(boot_info);
     ke.sched.late_init();
 
+    var timer: ke.Timer = undefined;
+    var dpc: ke.Dpc = .init(callback);
+
+    timer.init();
+
+    ke.timer.set(&timer, std.time.ns_per_ms * 50, &dpc);
+
     while (true) {
         std.atomic.spinLoopHint();
     }