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  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1992 NeXT Computer, Inc.
  27  *
  28  * Intel386 Family:     Floating Point unit.
  29  *
  30  * HISTORY
  31  *
  32  * 5 October 1992 ? at NeXT
  33  *      Added names to previously unamed fields in the mantissa.
  34  *
  35  * 5 April 1992 ? at NeXT
  36  *      Created.
  37  */
  38
  39 /*
  40  * Data register.
  41  */
  42
  43 typedef struct fp_data_reg {
  44     unsigned short              mant;
  45     unsigned short              mant1   :16,
  46                                 mant2   :16,
  47                                 mant3   :16;
  48     unsigned short              exp     :15,
  49                                 sign    :1;
  50 } fp_data_reg_t;
  51
  52 /*
  53  * Data register stack.
  54  */
  55
  56 typedef struct fp_stack {
  57     fp_data_reg_t               ST[8];
  58 } fp_stack_t;
  59
  60 /*
  61  * Register stack tag word.
  62  */
  63
  64 typedef struct fp_tag {
  65     unsigned short              tag0    :2,
  66                                 tag1    :2,
  67                                 tag2    :2,
  68                                 tag3    :2,
  69                                 tag4    :2,
  70                                 tag5    :2,
  71                                 tag6    :2,
  72                                 tag7    :2;
  73 #define FP_TAG_VALID            0
  74 #define FP_TAG_ZERO             1
  75 #define FP_TAG_SPEC             2
  76 #define FP_TAG_EMPTY            3
  77 } fp_tag_t;
  78
  79 /*
  80  * Status word.
  81  */
  82
  83 typedef struct fp_status {
  84     unsigned short              invalid :1,
  85                                 denorm  :1,
  86                                 zdiv    :1,
  87                                 ovrfl   :1,
  88                                 undfl   :1,
  89                                 precis  :1,
  90                                 stkflt  :1,
  91                                 errsumm :1,
  92                                 c0      :1,
  93                                 c1      :1,
  94                                 c2      :1,
  95                                 tos     :3,
  96                                 c3      :1,
  97                                 busy    :1;
  98 } fp_status_t;
  99
 100 /*
 101  * Control word.
 102  */
 103
 104 typedef struct fp_control {
 105     unsigned short              invalid :1,
 106                                 denorm  :1,
 107                                 zdiv    :1,
 108                                 ovrfl   :1,
 109                                 undfl   :1,
 110                                 precis  :1,
 111                                         :2,
 112                                 pc      :2,
 113 #define FP_PREC_24B             0
 114 #define FP_PREC_53B             2
 115 #define FP_PREC_64B             3
 116                                 rc      :2,
 117 #define FP_RND_NEAR             0
 118 #define FP_RND_DOWN             1
 119 #define FP_RND_UP               2
 120 #define FP_CHOP                 3
 121                                 /*inf*/ :1,
 122                                         :3;
 123 } fp_control_t;
 124
 125 #include <architecture/i386/sel.h>
 126
 127 /*
 128  * Floating point 'environment'
 129  * used by FSTENV/FLDENV instructions.
 130  */
 131
 132 typedef struct fp_env {
 133     fp_control_t                control;
 134     unsigned short                      :16;
 135     fp_status_t                 status;
 136     unsigned short                      :16;
 137     fp_tag_t                    tag;
 138     unsigned short                      :16;
 139     unsigned int                ip;
 140     sel_t                       cs;
 141     unsigned short              opcode;
 142     unsigned int                dp;
 143     sel_t                       ds;
 144     unsigned short                      :16;
 145 } fp_env_t;
 146
 147 /*
 148  * Floating point state
 149  * used by FSAVE/FRSTOR instructions.
 150  */
 151
 152 typedef struct fp_state {
 153     fp_env_t                    environ;
 154     fp_stack_t                  stack;
 155 } fp_state_t;