test

core/clock.c

@@ -0,0 +1,54 @@
+#include <zinnia/clock.h>
+#include <zinnia/compiler.h>
+#include <zinnia/print.h>
+#include <zinnia/spin.h>
+#include <stdatomic.h>
+#include <stdint.h>
+
+static struct clock* active_clock = nullptr;
+static uint64_t counter_base = 0;
+static struct spinlock lock = {};
+
+bool clock_available() {
+    return active_clock != nullptr;
+}
+
+uint64_t clock_get_elapsed_ns() {
+    struct clock* active = atomic_load(&active_clock);
+    if (__unlikely(!active))
+        return 0;
+
+    return atomic_load(&counter_base) + active->get_elapsed_ns(active);
+}
+
+bool clock_switch(struct clock* clock) {
+    spin_lock(&lock);
+
+    if (active_clock) {
+        if (clock->priority <= active_clock->priority) {
+            spin_unlock(&lock);
+            return false;
+        }
+    }
+
+    printf("Switching to clock source \"%s\"\n", clock->name);
+
+    uint64_t elapsed = clock_get_elapsed_ns();
+    counter_base += elapsed;
+
+    active_clock = clock;
+    spin_unlock(&lock);
+    return true;
+}
+
+void clock_spin_ns(uint64_t ns) {
+    if (active_clock == nullptr) {
+        printf("Unable to sleep for %lu ns, no clock available!\n", ns);
+        return;
+    }
+
+    uint64_t target = clock_get_elapsed_ns() + ns;
+    while (clock_get_elapsed_ns() < target) {
+        // TODO: Maybe pause?
+    }
+}