include/floatformat.h

   1 /* IEEE floating point support declarations, for GDB, the GNU Debugger.
   2    Copyright 1991, 1994, 1995, 1997, 2000, 2003, 2005
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GDB.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  20
  21 #if !defined (FLOATFORMAT_H)
  22 #define FLOATFORMAT_H 1
  23
  24 #include "ansidecl.h"
  25
  26 /* A floatformat consists of a sign bit, an exponent and a mantissa.  Once the
  27    bytes are concatenated according to the byteorder flag, then each of those
  28    fields is contiguous.  We number the bits with 0 being the most significant
  29    (i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field
  30    contains with the *_start and *_len fields.  */
  31
  32 /* What is the order of the bytes. */
  33
  34 enum floatformat_byteorders {
  35
  36   /* Standard little endian byte order.
  37      EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */
  38
  39   floatformat_little,
  40
  41   /* Standard big endian byte order.
  42      EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */
  43
  44   floatformat_big,
  45
  46   /* Little endian byte order but big endian word order.
  47      EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */
  48
  49   floatformat_littlebyte_bigword
  50
  51 };
  52
  53 enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no };
  54
  55 struct floatformat
  56 {
  57   enum floatformat_byteorders byteorder;
  58   unsigned int totalsize;       /* Total size of number in bits */
  59
  60   /* Sign bit is always one bit long.  1 means negative, 0 means positive.  */
  61   unsigned int sign_start;
  62
  63   unsigned int exp_start;
  64   unsigned int exp_len;
  65   /* Bias added to a "true" exponent to form the biased exponent.  It
  66      is intentionally signed as, otherwize, -exp_bias can turn into a
  67      very large number (e.g., given the exp_bias of 0x3fff and a 64
  68      bit long, the equation (long)(1 - exp_bias) evaluates to
  69      4294950914) instead of -16382).  */
  70   int exp_bias;
  71   /* Exponent value which indicates NaN.  This is the actual value stored in
  72      the float, not adjusted by the exp_bias.  This usually consists of all
  73      one bits.  */
  74   unsigned int exp_nan;
  75
  76   unsigned int man_start;
  77   unsigned int man_len;
  78
  79   /* Is the integer bit explicit or implicit?  */
  80   enum floatformat_intbit intbit;
  81
  82   /* Internal name for debugging. */
  83   const char *name;
  84
  85   /* Validator method.  */
  86   int (*is_valid) (const struct floatformat *fmt, const void *from);
  87 };
  88
  89 /* floatformats for IEEE single and double, big and little endian.  */
  90
  91 extern const struct floatformat floatformat_ieee_single_big;
  92 extern const struct floatformat floatformat_ieee_single_little;
  93 extern const struct floatformat floatformat_ieee_double_big;
  94 extern const struct floatformat floatformat_ieee_double_little;
  95
  96 /* floatformat for ARM IEEE double, little endian bytes and big endian words */
  97
  98 extern const struct floatformat floatformat_ieee_double_littlebyte_bigword;
  99
 100 /* floatformats for various extendeds.  */
 101
 102 extern const struct floatformat floatformat_i387_ext;
 103 extern const struct floatformat floatformat_m68881_ext;
 104 extern const struct floatformat floatformat_i960_ext;
 105 extern const struct floatformat floatformat_m88110_ext;
 106 extern const struct floatformat floatformat_m88110_harris_ext;
 107 extern const struct floatformat floatformat_arm_ext_big;
 108 extern const struct floatformat floatformat_arm_ext_littlebyte_bigword;
 109 /* IA-64 Floating Point register spilt into memory.  */
 110 extern const struct floatformat floatformat_ia64_spill_big;
 111 extern const struct floatformat floatformat_ia64_spill_little;
 112 extern const struct floatformat floatformat_ia64_quad_big;
 113 extern const struct floatformat floatformat_ia64_quad_little;
 114
 115 /* Convert from FMT to a double.
 116    FROM is the address of the extended float.
 117    Store the double in *TO.  */
 118
 119 extern void
 120 floatformat_to_double (const struct floatformat *, const void *, double *);
 121
 122 /* The converse: convert the double *FROM to FMT
 123    and store where TO points.  */
 124
 125 extern void
 126 floatformat_from_double (const struct floatformat *, const double *, void *);
 127
 128 /* Return non-zero iff the data at FROM is a valid number in format FMT.  */
 129
 130 extern int
 131 floatformat_is_valid (const struct floatformat *fmt, const void *from);
 132
 133 #endif  /* defined (FLOATFORMAT_H) */