EXTERNAL_HEADERS/architecture/i386/fpu.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  * Copyright (c) 1992 NeXT Computer, Inc.
  32  *
  33  * Intel386 Family:     Floating Point unit.
  34  *
  35  * HISTORY
  36  *
  37  * 5 October 1992 ? at NeXT
  38  *      Added names to previously unamed fields in the mantissa.
  39  *
  40  * 5 April 1992 ? at NeXT
  41  *      Created.
  42  */
  43
  44 /*
  45  * Data register.
  46  */
  47
  48 typedef struct fp_data_reg {
  49     unsigned short              mant;
  50     unsigned short              mant1   :16,
  51                                 mant2   :16,
  52                                 mant3   :16;
  53     unsigned short              exp     :15,
  54                                 sign    :1;
  55 } fp_data_reg_t;
  56
  57 /*
  58  * Data register stack.
  59  */
  60
  61 typedef struct fp_stack {
  62     fp_data_reg_t               ST[8];
  63 } fp_stack_t;
  64
  65 /*
  66  * Register stack tag word.
  67  */
  68
  69 typedef struct fp_tag {
  70     unsigned short              tag0    :2,
  71                                 tag1    :2,
  72                                 tag2    :2,
  73                                 tag3    :2,
  74                                 tag4    :2,
  75                                 tag5    :2,
  76                                 tag6    :2,
  77                                 tag7    :2;
  78 #define FP_TAG_VALID            0
  79 #define FP_TAG_ZERO             1
  80 #define FP_TAG_SPEC             2
  81 #define FP_TAG_EMPTY            3
  82 } fp_tag_t;
  83
  84 /*
  85  * Status word.
  86  */
  87
  88 typedef struct fp_status {
  89     unsigned short              invalid :1,
  90                                 denorm  :1,
  91                                 zdiv    :1,
  92                                 ovrfl   :1,
  93                                 undfl   :1,
  94                                 precis  :1,
  95                                 stkflt  :1,
  96                                 errsumm :1,
  97                                 c0      :1,
  98                                 c1      :1,
  99                                 c2      :1,
 100                                 tos     :3,
 101                                 c3      :1,
 102                                 busy    :1;
 103 } fp_status_t;
 104
 105 /*
 106  * Control word.
 107  */
 108
 109 typedef struct fp_control {
 110     unsigned short              invalid :1,
 111                                 denorm  :1,
 112                                 zdiv    :1,
 113                                 ovrfl   :1,
 114                                 undfl   :1,
 115                                 precis  :1,
 116                                         :2,
 117                                 pc      :2,
 118 #define FP_PREC_24B             0
 119 #define FP_PREC_53B             2
 120 #define FP_PREC_64B             3
 121                                 rc      :2,
 122 #define FP_RND_NEAR             0
 123 #define FP_RND_DOWN             1
 124 #define FP_RND_UP               2
 125 #define FP_CHOP                 3
 126                                 /*inf*/ :1,
 127                                         :3;
 128 } fp_control_t;
 129
 130 #include <architecture/i386/sel.h>
 131
 132 /*
 133  * Floating point 'environment'
 134  * used by FSTENV/FLDENV instructions.
 135  */
 136
 137 typedef struct fp_env {
 138     fp_control_t                control;
 139     unsigned short                      :16;
 140     fp_status_t                 status;
 141     unsigned short                      :16;
 142     fp_tag_t                    tag;
 143     unsigned short                      :16;
 144     unsigned int                ip;
 145     sel_t                       cs;
 146     unsigned short              opcode;
 147     unsigned int                dp;
 148     sel_t                       ds;
 149     unsigned short                      :16;
 150 } fp_env_t;
 151
 152 /*
 153  * Floating point state
 154  * used by FSAVE/FRSTOR instructions.
 155  */
 156
 157 typedef struct fp_state {
 158     fp_env_t                    environ;
 159     fp_stack_t                  stack;
 160 } fp_state_t;