Missing from previous checkin.

This is the core portion of the async I/O interface.

src/core/async.c

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <errno.h>
+#include <gpxe/process.h>
+#include <gpxe/async.h>
+
+/** @file
+ *
+ * Asynchronous operations
+ *
+ */
+
+/**
+ * Wait for asynchronous operation to complete
+ *
+ * @v aop		Asynchronous operation
+ * @ret rc		Return status code
+ *
+ * Blocks until the specified asynchronous operation has completed.
+ * The return status is the return status of the asynchronous
+ * operation itself.
+ */
+int async_wait ( struct async_operation *aop ) {
+	int rc;
+
+	/* Wait for operation to complete */
+	do {
+		step();
+		rc = async_status ( aop );
+	} while ( rc == -EINPROGRESS );
+	
+	/* Prepare for next call to async_wait() */
+	async_set_status ( aop, -EINPROGRESS );
+
+	return rc;
+}