Initial project import

tools/v/vlib/x/atomics/examples/spinlock.v

@@ -0,0 +1,59 @@
+module main
+
+import x.atomics
+
+struct SpinLock {
+mut:
+	state u32 // 0 = unlocked, 1 = locked
+}
+
+fn acquire(mut spinlock SpinLock) {
+	for !atomics.cas_u32(&spinlock.state, 0, 1) {
+		// Busy-wait
+	}
+}
+
+fn release(mut spinlock SpinLock) {
+	atomics.store_u32(&spinlock.state, 0)
+}
+
+struct SharedData {
+mut:
+	spinlock SpinLock
+	value    int
+}
+
+fn worker(mut data SharedData, iterations int) {
+	for _ in 0 .. iterations {
+		acquire(mut data.spinlock)
+		data.value++
+		release(mut data.spinlock)
+	}
+}
+
+fn main() {
+	mut data := &SharedData{}
+
+	num_threads := 4
+	iterations_per_thread := 10000
+
+	mut threads := []thread{}
+
+	for _ in 0 .. num_threads {
+		threads << spawn worker(mut data, iterations_per_thread)
+	}
+
+	threads.wait()
+
+	expected := num_threads * iterations_per_thread
+	actual := data.value
+
+	println('Expected: ${expected}')
+	println('Actual:   ${actual}')
+
+	if actual == expected {
+		println('Spinlock works correctly')
+	} else {
+		println('Race condition detected')
+	}
+}