support for the Genode OS framework (#5560)

lib/genode_cpp/syslocks.h

@@ -0,0 +1,78 @@
+/*
+ *
+ *           Nim's Runtime Library
+ *       (c) Copyright 2017 Emery Hemingway
+ *
+ *   See the file "copying.txt", included in this
+ *   distribution, for details about the copyright.
+ *
+ */
+
+#ifndef _GENODE_CPP__SYSLOCKS_H_
+#define _GENODE_CPP__SYSLOCKS_H_
+
+/* Genode includes */
+#include <base/semaphore.h>
+#include <base/lock.h>
+
+namespace Nim {
+	struct SysLock;
+	struct SysCond;
+}
+
+struct Nim::SysLock
+{
+	Genode::Lock _lock_a, _lock_b;
+	bool         _locked;
+
+	void acquireSys()
+	{
+		_lock_a.lock();
+		_locked = true;
+		_lock_a.unlock();
+		_lock_b.lock();
+	}
+
+	bool tryAcquireSys()
+	{
+		if (_locked)
+			return false;
+
+		_lock_a.lock();
+		if (_locked) {
+			_lock_a.unlock();
+			return false;
+		} else {
+			_locked = true;
+			_lock_b.lock();
+			_lock_a.unlock();
+			return true;
+		}
+	}
+
+	void releaseSys()
+	{
+		_locked = false;
+		_lock_a.unlock();
+		_lock_b.unlock();
+	}
+};
+
+struct Nim::SysCond
+{
+	Genode::Semaphore _semaphore;
+
+	void waitSysCond(SysLock &syslock)
+	{
+		syslock.releaseSys();
+		_semaphore.down();
+		syslock.acquireSys();
+	}
+
+	void signalSysCond()
+	{
+		_semaphore.up();
+	}
+};
+
+#endif