1 files changed, 118 insertions, 0 deletions
diff --git a/libgo/runtime/thread.c b/libgo/runtime/thread.c
new file mode 100644
index 000000000..bac3f7dfd
--- /dev/null
+++ b/libgo/runtime/thread.c
@@ -0,0 +1,118 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include <errno.h>
+#include "runtime.h"
+#include "go-assert.h"
+
+void
+runtime_initlock(Lock *l)
+{
+	l->key = 0;
+	if(sem_init(&l->sem, 0, 0) != 0)
+		runtime_throw("sem_init failed");
+}
+
+static uint32
+runtime_xadd(uint32 volatile *val, int32 delta)
+{
+	uint32 oval, nval;
+
+	for(;;){
+		oval = *val;
+		nval = oval + delta;
+		if(runtime_cas(val, oval, nval))
+			return nval;
+	}
+}
+
+// noinline so that runtime_lock doesn't have to split the stack.
+static void runtime_lock_full(Lock *l) __attribute__ ((noinline));
+
+static void
+runtime_lock_full(Lock *l)
+{
+	for(;;){
+		if(sem_wait(&l->sem) == 0)
+			return;
+		if(errno != EINTR)
+			runtime_throw("sem_wait failed");
+	}
+}
+
+void
+runtime_lock(Lock *l)
+{
+	if(m != nil) {
+		if(m->locks < 0)
+			runtime_throw("lock count");
+		m->locks++;
+	}
+
+	if(runtime_xadd(&l->key, 1) > 1)	// someone else has it; wait
+		runtime_lock_full(l);
+}
+
+static void runtime_unlock_full(Lock *l) __attribute__ ((noinline));
+
+static void
+runtime_unlock_full(Lock *l)
+{
+	if(sem_post(&l->sem) != 0)
+		runtime_throw("sem_post failed");
+}
+
+void
+runtime_unlock(Lock *l)
+{
+	if(m != nil) {
+		m->locks--;
+		if(m->locks < 0)
+			runtime_throw("lock count");
+	}
+
+	if(runtime_xadd(&l->key, -1) > 0)	// someone else is waiting
+		runtime_unlock_full(l);
+}
+
+void
+runtime_destroylock(Lock *l)
+{
+	sem_destroy(&l->sem);
+}
+
+#ifndef HAVE_SYNC_BOOL_COMPARE_AND_SWAP_4
+
+// For targets which don't have the required sync support.  Really
+// this should be provided by gcc itself.  FIXME.
+
+static pthread_mutex_t sync_lock = PTHREAD_MUTEX_INITIALIZER;
+
+_Bool
+__sync_bool_compare_and_swap_4(uint32*, uint32, uint32)
+  __attribute__((visibility("hidden")));
+
+_Bool
+__sync_bool_compare_and_swap_4(uint32* ptr, uint32 old, uint32 new)
+{
+  int i;
+  _Bool ret;
+
+  i = pthread_mutex_lock(&sync_lock);
+  __go_assert(i == 0);
+
+  if(*ptr != old) {
+    ret = 0;
+  } else {
+    *ptr = new;
+    ret = 1;
+  }
+
+  i = pthread_mutex_unlock(&sync_lock);
+  __go_assert(i == 0);
+
+  return ret;
+}
+
+#endif