more new libthread

src/libthread/ref.c

@@ -0,0 +1,27 @@
+#include "u.h"
+#include "libc.h"
+#include "thread.h"
+
+static long
+refadd(Ref *r, long a)
+{
+	long ref;
+
+	lock(&r->lock);
+	r->ref += a;
+	ref = r->ref;
+	unlock(&r->lock);
+	return ref;
+}
+
+long
+incref(Ref *r)
+{
+	return refadd(r, 1);
+}
+
+long
+decref(Ref *r)
+{
+	return refadd(r, -1);
+}