EXTERNAL_HEADERS/architecture/i386/fpu.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:     Floating Point unit.
  32  *
  33  * HISTORY
  34  *
  35  * 5 October 1992 ? at NeXT
  36  *      Added names to previously unamed fields in the mantissa.
  37  *
  38  * 5 April 1992 ? at NeXT
  39  *      Created.
  40  */
  41
  42 /*
  43  * Data register.
  44  */
  45
  46 typedef struct fp_data_reg {
  47     unsigned short              mant;
  48     unsigned short              mant1   :16,
  49                                 mant2   :16,
  50                                 mant3   :16;
  51     unsigned short              exp     :15,
  52                                 sign    :1;
  53 } fp_data_reg_t;
  54
  55 /*
  56  * Data register stack.
  57  */
  58
  59 typedef struct fp_stack {
  60     fp_data_reg_t               ST[8];
  61 } fp_stack_t;
  62
  63 /*
  64  * Register stack tag word.
  65  */
  66
  67 typedef struct fp_tag {
  68     unsigned short              tag0    :2,
  69                                 tag1    :2,
  70                                 tag2    :2,
  71                                 tag3    :2,
  72                                 tag4    :2,
  73                                 tag5    :2,
  74                                 tag6    :2,
  75                                 tag7    :2;
  76 #define FP_TAG_VALID            0
  77 #define FP_TAG_ZERO             1
  78 #define FP_TAG_SPEC             2
  79 #define FP_TAG_EMPTY            3
  80 } fp_tag_t;
  81
  82 /*
  83  * Status word.
  84  */
  85
  86 typedef struct fp_status {
  87     unsigned short              invalid :1,
  88                                 denorm  :1,
  89                                 zdiv    :1,
  90                                 ovrfl   :1,
  91                                 undfl   :1,
  92                                 precis  :1,
  93                                 stkflt  :1,
  94                                 errsumm :1,
  95                                 c0      :1,
  96                                 c1      :1,
  97                                 c2      :1,
  98                                 tos     :3,
  99                                 c3      :1,
 100                                 busy    :1;
 101 } fp_status_t;
 102
 103 /*
 104  * Control word.
 105  */
 106
 107 typedef struct fp_control {
 108     unsigned short              invalid :1,
 109                                 denorm  :1,
 110                                 zdiv    :1,
 111                                 ovrfl   :1,
 112                                 undfl   :1,
 113                                 precis  :1,
 114                                         :2,
 115                                 pc      :2,
 116 #define FP_PREC_24B             0
 117 #define FP_PREC_53B             2
 118 #define FP_PREC_64B             3
 119                                 rc      :2,
 120 #define FP_RND_NEAR             0
 121 #define FP_RND_DOWN             1
 122 #define FP_RND_UP               2
 123 #define FP_CHOP                 3
 124                                 /*inf*/ :1,
 125                                         :3;
 126 } fp_control_t;
 127
 128 #include <architecture/i386/sel.h>
 129
 130 /*
 131  * Floating point 'environment'
 132  * used by FSTENV/FLDENV instructions.
 133  */
 134
 135 typedef struct fp_env {
 136     fp_control_t                control;
 137     unsigned short                      :16;
 138     fp_status_t                 status;
 139     unsigned short                      :16;
 140     fp_tag_t                    tag;
 141     unsigned short                      :16;
 142     unsigned int                ip;
 143     sel_t                       cs;
 144     unsigned short              opcode;
 145     unsigned int                dp;
 146     sel_t                       ds;
 147     unsigned short                      :16;
 148 } fp_env_t;
 149
 150 /*
 151  * Floating point state
 152  * used by FSAVE/FRSTOR instructions.
 153  */
 154
 155 typedef struct fp_state {
 156     fp_env_t                    environ;
 157     fp_stack_t                  stack;
 158 } fp_state_t;