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  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1992 NeXT Computer, Inc.
  24  *
  25  * Intel386 Family:     Floating Point unit.
  26  *
  27  * HISTORY
  28  *
  29  * 5 October 1992 ? at NeXT
  30  *      Added names to previously unamed fields in the mantissa.
  31  *
  32  * 5 April 1992 ? at NeXT
  33  *      Created.
  34  */
  35
  36 /*
  37  * Data register.
  38  */
  39
  40 typedef struct fp_data_reg {
  41     unsigned short              mant;
  42     unsigned short              mant1   :16,
  43                                 mant2   :16,
  44                                 mant3   :16;
  45     unsigned short              exp     :15,
  46                                 sign    :1;
  47 } fp_data_reg_t;
  48
  49 /*
  50  * Data register stack.
  51  */
  52
  53 typedef struct fp_stack {
  54     fp_data_reg_t               ST[8];
  55 } fp_stack_t;
  56
  57 /*
  58  * Register stack tag word.
  59  */
  60
  61 typedef struct fp_tag {
  62     unsigned short              tag0    :2,
  63                                 tag1    :2,
  64                                 tag2    :2,
  65                                 tag3    :2,
  66                                 tag4    :2,
  67                                 tag5    :2,
  68                                 tag6    :2,
  69                                 tag7    :2;
  70 #define FP_TAG_VALID            0
  71 #define FP_TAG_ZERO             1
  72 #define FP_TAG_SPEC             2
  73 #define FP_TAG_EMPTY            3
  74 } fp_tag_t;
  75
  76 /*
  77  * Status word.
  78  */
  79
  80 typedef struct fp_status {
  81     unsigned short              invalid :1,
  82                                 denorm  :1,
  83                                 zdiv    :1,
  84                                 ovrfl   :1,
  85                                 undfl   :1,
  86                                 precis  :1,
  87                                 stkflt  :1,
  88                                 errsumm :1,
  89                                 c0      :1,
  90                                 c1      :1,
  91                                 c2      :1,
  92                                 tos     :3,
  93                                 c3      :1,
  94                                 busy    :1;
  95 } fp_status_t;
  96
  97 /*
  98  * Control word.
  99  */
 100
 101 typedef struct fp_control {
 102     unsigned short              invalid :1,
 103                                 denorm  :1,
 104                                 zdiv    :1,
 105                                 ovrfl   :1,
 106                                 undfl   :1,
 107                                 precis  :1,
 108                                         :2,
 109                                 pc      :2,
 110 #define FP_PREC_24B             0
 111 #define FP_PREC_53B             2
 112 #define FP_PREC_64B             3
 113                                 rc      :2,
 114 #define FP_RND_NEAR             0
 115 #define FP_RND_DOWN             1
 116 #define FP_RND_UP               2
 117 #define FP_CHOP                 3
 118                                 /*inf*/ :1,
 119                                         :3;
 120 } fp_control_t;
 121
 122 #include <architecture/i386/sel.h>
 123
 124 /*
 125  * Floating point 'environment'
 126  * used by FSTENV/FLDENV instructions.
 127  */
 128
 129 typedef struct fp_env {
 130     fp_control_t                control;
 131     unsigned short                      :16;
 132     fp_status_t                 status;
 133     unsigned short                      :16;
 134     fp_tag_t                    tag;
 135     unsigned short                      :16;
 136     unsigned int                ip;
 137     sel_t                       cs;
 138     unsigned short              opcode;
 139     unsigned int                dp;
 140     sel_t                       ds;
 141     unsigned short                      :16;
 142 } fp_env_t;
 143
 144 /*
 145  * Floating point state
 146  * used by FSAVE/FRSTOR instructions.
 147  */
 148
 149 typedef struct fp_state {
 150     fp_env_t                    environ;
 151     fp_stack_t                  stack;
 152 } fp_state_t;