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authorThomas Bushnell <thomas@gnu.org>1997-02-25 21:28:37 +0000
committerThomas Bushnell <thomas@gnu.org>1997-02-25 21:28:37 +0000
commitf07a4c844da9f0ecae5bbee1ab94be56505f26f7 (patch)
tree12b07c7e578fc1a5f53dbfde2632408491ff2a70 /ipc/port.h
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+/*
+ * Mach Operating System
+ * Copyright (c) 1991,1990,1989 Carnegie Mellon University.
+ * Copyright (c) 1993,1994 The University of Utah and
+ * the Computer Systems Laboratory (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON, THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF
+ * THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM ANY LIABILITY
+ * OF ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF
+ * THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
+ * School of Computer Science
+ * Carnegie Mellon University
+ * Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+/*
+ */
+/*
+ * File: ipc/ipc_port.h
+ * Author: Rich Draves
+ * Date: 1989
+ *
+ * Implementation specific complement to mach/port.h.
+ */
+
+#ifndef _IPC_PORT_H_
+#define _IPC_PORT_H_
+
+#include <mach/port.h>
+
+/*
+ * mach_port_t must be an unsigned type. Port values
+ * have two parts, a generation number and an index.
+ * These macros encapsulate all knowledge of how
+ * a mach_port_t is layed out. However, ipc/ipc_entry.c
+ * implicitly assumes when it uses the splay tree functions
+ * that the generation number is in the low bits, so that
+ * names are ordered first by index and then by generation.
+ *
+ * If the size of generation numbers changes,
+ * be sure to update IE_BITS_GEN_MASK and friends
+ * in ipc/ipc_entry.h.
+ */
+
+#if PORT_GENERATIONS
+#define MACH_PORT_INDEX(name) ((name) >> 8)
+#define MACH_PORT_GEN(name) (((name) & 0xff) << 24)
+#define MACH_PORT_MAKE(index, gen) (((index) << 8) | ((gen) >> 24))
+#else
+#define MACH_PORT_INDEX(name) (name)
+#define MACH_PORT_GEN(name) 0
+#define MACH_PORT_MAKE(index, gen) (index)
+#endif
+
+#define MACH_PORT_NGEN(name) MACH_PORT_MAKE(0, MACH_PORT_GEN(name))
+#define MACH_PORT_MAKEB(index, bits) MACH_PORT_MAKE(index, IE_BITS_GEN(bits))
+
+/*
+ * Typedefs for code cleanliness. These must all have
+ * the same (unsigned) type as mach_port_t.
+ */
+
+typedef mach_port_t mach_port_index_t; /* index values */
+typedef mach_port_t mach_port_gen_t; /* generation numbers */
+
+
+#define MACH_PORT_UREFS_MAX ((mach_port_urefs_t) ((1 << 16) - 1))
+
+#define MACH_PORT_UREFS_OVERFLOW(urefs, delta) \
+ (((delta) > 0) && \
+ ((((urefs) + (delta)) <= (urefs)) || \
+ (((urefs) + (delta)) > MACH_PORT_UREFS_MAX)))
+
+#define MACH_PORT_UREFS_UNDERFLOW(urefs, delta) \
+ (((delta) < 0) && (-(delta) > (urefs)))
+
+#endif /* _IPC_PORT_H_ */