core: Add spinlock code

core/src/lib/spinlock.zig

@@ -0,0 +1,24 @@
+const std = @import("std");
+const debug = @import("../arch/debug.zig");
+
+pub const SpinLock = struct {
+    lock_value: std.atomic.Value(u32) = std.atomic.Value(u32).init(0),
+
+    pub fn lock(self: *SpinLock) void {
+        while (self.lock_value.cmpxchgWeak(0, 1, .seq_cst, .seq_cst) != null) {}
+    }
+
+    pub fn unlock(self: *SpinLock) void {
+        if (self.lock_value.cmpxchgStrong(1, 0, .seq_cst, .seq_cst) != null) {
+            debug.print("Error: SpinLock.unlock() called on an unlocked lock!\n", .{});
+        }
+    }
+
+    pub fn tryLock(self: *SpinLock) bool {
+        return self.lock_value.cmpxchgStrong(0, 1, .seq_cst, .seq_cst) == null;
+    }
+
+    pub fn isLocked(self: *SpinLock) bool {
+        return self.lock_value.load() != 0;
+    }
+};