FreeBSD/Linux Kernel Cross Reference
sys/i386/include/psl.h
1 /*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * from: @(#)psl.h 5.2 (Berkeley) 1/18/91
33 * $FreeBSD$
34 */
35
36 #ifndef _MACHINE_PSL_H_
37 #define _MACHINE_PSL_H_
38
39 /*
40 * 386 processor status longword.
41 */
42 #define PSL_C 0x00000001 /* carry bit */
43 #define PSL_PF 0x00000004 /* parity bit */
44 #define PSL_AF 0x00000010 /* bcd carry bit */
45 #define PSL_Z 0x00000040 /* zero bit */
46 #define PSL_N 0x00000080 /* negative bit */
47 #define PSL_T 0x00000100 /* trace enable bit */
48 #define PSL_I 0x00000200 /* interrupt enable bit */
49 #define PSL_D 0x00000400 /* string instruction direction bit */
50 #define PSL_V 0x00000800 /* overflow bit */
51 #define PSL_IOPL 0x00003000 /* i/o privilege level */
52 #define PSL_NT 0x00004000 /* nested task bit */
53 #define PSL_RF 0x00010000 /* resume flag bit */
54 #define PSL_VM 0x00020000 /* virtual 8086 mode bit */
55 #define PSL_AC 0x00040000 /* alignment checking */
56 #define PSL_VIF 0x00080000 /* virtual interrupt enable */
57 #define PSL_VIP 0x00100000 /* virtual interrupt pending */
58 #define PSL_ID 0x00200000 /* identification bit */
59
60 /*
61 * The i486 manual says that we are not supposed to change reserved flags,
62 * but this is too much trouble since the reserved flags depend on the cpu
63 * and setting them to their historical values works in practice.
64 */
65 #define PSL_RESERVED_DEFAULT 0x00000002
66
67 /*
68 * Initial flags for kernel and user mode. The kernel later inherits
69 * PSL_I and some other flags from user mode.
70 */
71 #define PSL_KERNEL PSL_RESERVED_DEFAULT
72 #define PSL_USER (PSL_RESERVED_DEFAULT | PSL_I)
73
74 /*
75 * Bits that can be changed in user mode on 486's. We allow these bits
76 * to be changed using ptrace(), sigreturn() and procfs. Setting PS_NT
77 * is undesirable but it may as well be allowed since users can inflict
78 * it on the kernel directly. Changes to PSL_AC are silently ignored on
79 * 386's.
80 */
81 #define PSL_USERCHANGE (PSL_C | PSL_PF | PSL_AF | PSL_Z | PSL_N | PSL_T \
82 | PSL_D | PSL_V | PSL_NT | PSL_AC | PSL_ID)
83
84 #endif /* !_MACHINE_PSL_H_ */
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