1 files changed, 63 insertions, 0 deletions
diff --git a/libpthread/sysdeps/l4/pt-spin.c b/libpthread/sysdeps/l4/pt-spin.c
new file mode 100644
index 00000000..b6978b0c
--- /dev/null
+++ b/libpthread/sysdeps/l4/pt-spin.c
@@ -0,0 +1,63 @@
+/* Spin locks.  L4 version.
+   Copyright (C) 2000, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <l4.h>
+
+#include <pthread.h>
+#include <sched.h>
+
+/* The default for single processor machines; don't spin, it's
+   pointless.  */
+#ifndef __PTHREAD_SPIN_COUNT
+# define __PTHREAD_SPIN_COUNT 1
+#endif
+
+/* The number of times to spin while trying to lock a spin lock object
+   before yielding the processor. */
+int __pthread_spin_count = __PTHREAD_SPIN_COUNT;
+
+
+/* Lock the spin lock object LOCK.  If the lock is held by another
+   thread spin until it becomes available.  */
+int
+_pthread_spin_lock (__pthread_spinlock_t *lock)
+{
+  l4_time_t timeout;
+  int i;
+
+  /* Start with a small timeout of 2 microseconds, then back off
+     exponentially.  */
+  timeout = l4_time_period (2);
+
+  while (1)
+    {
+      for (i = 0; i < __pthread_spin_count; i++)
+	{
+	  if (__pthread_spin_trylock (lock) == 0)
+	    return 0;
+	}
+      l4_sleep (timeout);
+
+      timeout = l4_time_mul2 (timeout);
+      if (timeout == L4_NEVER)
+	timeout = L4_TIME_PERIOD_MAX;
+    }
+}
+
+weak_alias (_pthread_spin_lock, pthread_spin_lock);