include/floatformat.h

   1 /* IEEE floating point support declarations, for GDB, the GNU Debugger.
   2    Copyright 1991, 1994, 1995, 1997, 2000 Free Software Foundation, Inc.
   3
   4 This file is part of GDB.
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 #if !defined (FLOATFORMAT_H)
  21 #define FLOATFORMAT_H 1
  22
  23 #include "ansidecl.h"
  24
  25 /* A floatformat consists of a sign bit, an exponent and a mantissa.  Once the
  26    bytes are concatenated according to the byteorder flag, then each of those
  27    fields is contiguous.  We number the bits with 0 being the most significant
  28    (i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field
  29    contains with the *_start and *_len fields.  */
  30
  31 /* What is the order of the bytes. */
  32
  33 enum floatformat_byteorders {
  34
  35   /* Standard little endian byte order.
  36      EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */
  37
  38   floatformat_little,
  39
  40   /* Standard big endian byte order.
  41      EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */
  42
  43   floatformat_big,
  44
  45   /* Little endian byte order but big endian word order.
  46      EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */
  47
  48   floatformat_littlebyte_bigword
  49
  50 };
  51
  52 enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no };
  53
  54 struct floatformat
  55 {
  56   enum floatformat_byteorders byteorder;
  57   unsigned int totalsize;       /* Total size of number in bits */
  58
  59   /* Sign bit is always one bit long.  1 means negative, 0 means positive.  */
  60   unsigned int sign_start;
  61
  62   unsigned int exp_start;
  63   unsigned int exp_len;
  64   /* Amount added to "true" exponent.  0x3fff for many IEEE extendeds.  */
  65   unsigned int exp_bias;
  66   /* Exponent value which indicates NaN.  This is the actual value stored in
  67      the float, not adjusted by the exp_bias.  This usually consists of all
  68      one bits.  */
  69   unsigned int exp_nan;
  70
  71   unsigned int man_start;
  72   unsigned int man_len;
  73
  74   /* Is the integer bit explicit or implicit?  */
  75   enum floatformat_intbit intbit;
  76
  77   /* Internal name for debugging. */
  78   const char *name;
  79 };
  80
  81 /* floatformats for IEEE single and double, big and little endian.  */
  82
  83 extern const struct floatformat floatformat_ieee_single_big;
  84 extern const struct floatformat floatformat_ieee_single_little;
  85 extern const struct floatformat floatformat_ieee_double_big;
  86 extern const struct floatformat floatformat_ieee_double_little;
  87
  88 /* floatformat for ARM IEEE double, little endian bytes and big endian words */
  89
  90 extern const struct floatformat floatformat_ieee_double_littlebyte_bigword;
  91
  92 /* floatformats for various extendeds.  */
  93
  94 extern const struct floatformat floatformat_i387_ext;
  95 extern const struct floatformat floatformat_m68881_ext;
  96 extern const struct floatformat floatformat_i960_ext;
  97 extern const struct floatformat floatformat_m88110_ext;
  98 extern const struct floatformat floatformat_arm_ext;
  99
 100 /* Convert from FMT to a double.
 101    FROM is the address of the extended float.
 102    Store the double in *TO.  */
 103
 104 extern void
 105 floatformat_to_double PARAMS ((const struct floatformat *, char *, double *));
 106
 107 /* The converse: convert the double *FROM to FMT
 108    and store where TO points.  */
 109
 110 extern void
 111 floatformat_from_double PARAMS ((const struct floatformat *,
 112                                  double *, char *));
 113
 114 #endif  /* defined (FLOATFORMAT_H) */