EXTERNAL_HEADERS/architecture/i386/fpu.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * Copyright (c) 1992 NeXT Computer, Inc.
  25  *
  26  * Intel386 Family:     Floating Point unit.
  27  *
  28  * HISTORY
  29  *
  30  * 5 October 1992 ? at NeXT
  31  *      Added names to previously unamed fields in the mantissa.
  32  *
  33  * 5 April 1992 ? at NeXT
  34  *      Created.
  35  */
  36
  37 /*
  38  * Data register.
  39  */
  40
  41 typedef struct fp_data_reg {
  42     unsigned short              mant;
  43     unsigned short              mant1   :16,
  44                                 mant2   :16,
  45                                 mant3   :16;
  46     unsigned short              exp     :15,
  47                                 sign    :1;
  48 } fp_data_reg_t;
  49
  50 /*
  51  * Data register stack.
  52  */
  53
  54 typedef struct fp_stack {
  55     fp_data_reg_t               ST[8];
  56 } fp_stack_t;
  57
  58 /*
  59  * Register stack tag word.
  60  */
  61
  62 typedef struct fp_tag {
  63     unsigned short              tag0    :2,
  64                                 tag1    :2,
  65                                 tag2    :2,
  66                                 tag3    :2,
  67                                 tag4    :2,
  68                                 tag5    :2,
  69                                 tag6    :2,
  70                                 tag7    :2;
  71 #define FP_TAG_VALID            0
  72 #define FP_TAG_ZERO             1
  73 #define FP_TAG_SPEC             2
  74 #define FP_TAG_EMPTY            3
  75 } fp_tag_t;
  76
  77 /*
  78  * Status word.
  79  */
  80
  81 typedef struct fp_status {
  82     unsigned short              invalid :1,
  83                                 denorm  :1,
  84                                 zdiv    :1,
  85                                 ovrfl   :1,
  86                                 undfl   :1,
  87                                 precis  :1,
  88                                 stkflt  :1,
  89                                 errsumm :1,
  90                                 c0      :1,
  91                                 c1      :1,
  92                                 c2      :1,
  93                                 tos     :3,
  94                                 c3      :1,
  95                                 busy    :1;
  96 } fp_status_t;
  97
  98 /*
  99  * Control word.
 100  */
 101
 102 typedef struct fp_control {
 103     unsigned short              invalid :1,
 104                                 denorm  :1,
 105                                 zdiv    :1,
 106                                 ovrfl   :1,
 107                                 undfl   :1,
 108                                 precis  :1,
 109                                         :2,
 110                                 pc      :2,
 111 #define FP_PREC_24B             0
 112 #define FP_PREC_53B             2
 113 #define FP_PREC_64B             3
 114                                 rc      :2,
 115 #define FP_RND_NEAR             0
 116 #define FP_RND_DOWN             1
 117 #define FP_RND_UP               2
 118 #define FP_CHOP                 3
 119                                 /*inf*/ :1,
 120                                         :3;
 121 } fp_control_t;
 122
 123 #include <architecture/i386/sel.h>
 124
 125 /*
 126  * Floating point 'environment'
 127  * used by FSTENV/FLDENV instructions.
 128  */
 129
 130 typedef struct fp_env {
 131     fp_control_t                control;
 132     unsigned short                      :16;
 133     fp_status_t                 status;
 134     unsigned short                      :16;
 135     fp_tag_t                    tag;
 136     unsigned short                      :16;
 137     unsigned int                ip;
 138     sel_t                       cs;
 139     unsigned short              opcode;
 140     unsigned int                dp;
 141     sel_t                       ds;
 142     unsigned short                      :16;
 143 } fp_env_t;
 144
 145 /*
 146  * Floating point state
 147  * used by FSAVE/FRSTOR instructions.
 148  */
 149
 150 typedef struct fp_state {
 151     fp_env_t                    environ;
 152     fp_stack_t                  stack;
 153 } fp_state_t;