EXTERNAL_HEADERS/architecture/i386/desc.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * Copyright (c) 1992 NeXT Computer, Inc.
  30  *
  31  * Intel386 Family:     Segment descriptors.
  32  *
  33  * HISTORY
  34  *
  35  * 29 March 1992 ? at NeXT
  36  *      Created.
  37  */
  38
  39 /*
  40  * Code segment descriptor.
  41  */
  42
  43 typedef struct code_desc {
  44     unsigned short      limit00;
  45     unsigned short      base00;
  46     unsigned char       base16;
  47     unsigned char       type    :5,
  48 #define DESC_CODE_EXEC  0x18
  49 #define DESC_CODE_READ  0x1a
  50                         dpl     :2,
  51                         present :1;
  52     unsigned char       limit16 :4,
  53                                 :2,
  54                         opsz    :1,
  55 #define DESC_CODE_16B   0
  56 #define DESC_CODE_32B   1
  57                         granular:1;
  58 #define DESC_GRAN_BYTE  0
  59 #define DESC_GRAN_PAGE  1
  60     unsigned char       base24;
  61 } code_desc_t;
  62
  63 /*
  64  * Data segment descriptor.
  65  */
  66
  67 typedef struct data_desc {
  68     unsigned short      limit00;
  69     unsigned short      base00;
  70     unsigned char       base16;
  71     unsigned char       type    :5,
  72 #define DESC_DATA_RONLY 0x10
  73 #define DESC_DATA_WRITE 0x12
  74                         dpl     :2,
  75                         present :1;
  76     unsigned char       limit16 :4,
  77                                 :2,
  78                         stksz   :1,
  79 #define DESC_DATA_16B   0
  80 #define DESC_DATA_32B   1
  81                         granular:1;
  82     unsigned char       base24;
  83 } data_desc_t;
  84
  85 /*
  86  * LDT segment descriptor.
  87  */
  88
  89 typedef struct ldt_desc {
  90     unsigned short      limit00;
  91     unsigned short      base00;
  92     unsigned char       base16;
  93     unsigned char       type    :5,
  94 #define DESC_LDT        0x02
  95                                 :2,
  96                         present :1;
  97     unsigned char       limit16 :4,
  98                                 :3,
  99                         granular:1;
 100     unsigned char       base24;
 101 } ldt_desc_t;
 102
 103 #include <architecture/i386/sel.h>
 104
 105 /*
 106  * Call gate descriptor.
 107  */
 108
 109 typedef struct call_gate {
 110     unsigned short      offset00;
 111     sel_t               seg;
 112     unsigned int        argcnt  :5,
 113                                 :3,
 114                         type    :5,
 115 #define DESC_CALL_GATE  0x0c
 116                         dpl     :2,
 117                         present :1,
 118                         offset16:16;
 119 } call_gate_t;
 120
 121 /*
 122  * Trap gate descriptor.
 123  */
 124
 125 typedef struct trap_gate {
 126     unsigned short      offset00;
 127     sel_t               seg;
 128     unsigned int                :8,
 129                         type    :5,
 130 #define DESC_TRAP_GATE  0x0f
 131                         dpl     :2,
 132                         present :1,
 133                         offset16:16;
 134 } trap_gate_t;
 135
 136
 137 /*
 138  * Interrupt gate descriptor.
 139  */
 140
 141 typedef struct intr_gate {
 142     unsigned short      offset00;
 143     sel_t               seg;
 144     unsigned int                :8,
 145                         type    :5,
 146 #define DESC_INTR_GATE  0x0e
 147                         dpl     :2,
 148                         present :1,
 149                         offset16:16;
 150 } intr_gate_t;