1 files changed, 110 insertions, 0 deletions
diff --git a/src/kernel/KernelKit/Semaphore.h b/src/kernel/KernelKit/Semaphore.h
new file mode 100644
index 00000000..831774a5
--- /dev/null
+++ b/src/kernel/KernelKit/Semaphore.h
@@ -0,0 +1,110 @@
+/* ========================================
+
+  Copyright (C) 2024-2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
+
+======================================== */
+
+#pragma once
+
+/// @author Amlal El Mahrouss
+/// @file Semaphore.h
+/// @brief Semaphore structure and functions for synchronization in the kernel.
+
+#include <CompilerKit/CompilerKit.h>
+#include <KernelKit/Timer.h>
+#include <NeKit/Defines.h>
+
+#define kSemaphoreOwnerIndex (0U)
+#define kSemaphoreCountIndex (1U)
+
+#define kSemaphoreCount (2U)
+
+#define kSemaphoreIncrementOwner(sem) (sem[kSemaphoreOwnerIndex]++)
+#define kSemaphoreDecrementOwner(sem) (sem[kSemaphoreOwnerIndex]--)
+
+namespace Kernel {
+/// @brief Semaphore structure used for synchronization.
+typedef UInt64 SemaphoreArr[kSemaphoreCount];
+
+/// @brief Checks if the semaphore is valid.
+inline BOOL rtl_sem_is_valid(const SemaphoreArr& sem, UInt64 owner = 0) {
+  return sem[kSemaphoreOwnerIndex] == owner && sem[kSemaphoreCountIndex] > 0;
+}
+
+/// @brief Releases the semaphore, resetting its owner and count.
+/// @param sem
+/// @return
+inline BOOL rtl_sem_release(SemaphoreArr& sem) {
+  sem[kSemaphoreOwnerIndex] = 0;
+  sem[kSemaphoreCountIndex] = 0;
+
+  return TRUE;
+}
+
+/// @brief Initializes the semaphore with an owner and a count of zero.
+/// @param sem the semaphore array to use.
+/// @param owner the owner to set, could be anything identifitable.
+/// @return
+inline BOOL rtl_sem_acquire(SemaphoreArr& sem, UInt64 owner) {
+  if (!owner) {
+    err_global_get() = kErrorInvalidData;
+    return FALSE;  // Invalid owner
+  }
+
+  sem[kSemaphoreOwnerIndex] = owner;
+  sem[kSemaphoreCountIndex] = 0;
+
+  return TRUE;
+}
+
+/// @brief Waits for the semaphore to be available, blocking until it is.
+/// @param sem
+/// @param timeout
+/// @param condition condition pointer.
+/// @return
+inline BOOL rtl_sem_wait(SemaphoreArr& sem, UInt64 owner, UInt64 timeout,
+                         BOOL* condition = nullptr) {
+  if (!rtl_sem_is_valid(sem, owner)) {
+    return FALSE;
+  }
+
+  if (timeout <= 0) {
+    err_global_get() = kErrorTimeout;
+
+    return FALSE;
+  }
+
+  if (!condition || *condition) {
+    if (sem[kSemaphoreCountIndex] == 0) {
+      err_global_get() = kErrorUnavailable;
+      return FALSE;
+    }
+
+    err_global_get() = kErrorSuccess;
+    sem[kSemaphoreCountIndex]--;
+
+    return TRUE;
+  }
+
+  HardwareTimer timer(timeout);
+  BOOL          ret = timer.Wait();
+
+  if (ret) {
+    if (!condition || *condition) {
+      if (sem[kSemaphoreCountIndex] == 0) {
+        err_global_get() = kErrorUnavailable;
+        return FALSE;
+      }
+
+      err_global_get() = kErrorSuccess;
+      sem[kSemaphoreCountIndex]--;
+
+      return TRUE;
+    }
+  }
+
+  err_global_get() = kErrorTimeout;
+
+  return FALSE;  // Failed to acquire semaphore
+}
+}  // namespace Kernel
+\ No newline at end of file