include/floatformat.h

   1 /* IEEE floating point support declarations, for GDB, the GNU Debugger.
   2    Copyright 1991, 1994, 1995, 1997, 2000, 2003 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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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   /* Bias added to a "true" exponent to form the biased exponent.  It
  65      is intentionally signed as, otherwize, -exp_bias can turn into a
  66      very large number (e.g., given the exp_bias of 0x3fff and a 64
  67      bit long, the equation (long)(1 - exp_bias) evaluates to
  68      4294950914) instead of -16382).  */
  69   int exp_bias;
  70   /* Exponent value which indicates NaN.  This is the actual value stored in
  71      the float, not adjusted by the exp_bias.  This usually consists of all
  72      one bits.  */
  73   unsigned int exp_nan;
  74
  75   unsigned int man_start;
  76   unsigned int man_len;
  77
  78   /* Is the integer bit explicit or implicit?  */
  79   enum floatformat_intbit intbit;
  80
  81   /* Internal name for debugging. */
  82   const char *name;
  83
  84   /* Validator method.  */
  85   int (*is_valid) (const struct floatformat *fmt, const char *from);
  86 };
  87
  88 /* floatformats for IEEE single and double, big and little endian.  */
  89
  90 extern const struct floatformat floatformat_ieee_single_big;
  91 extern const struct floatformat floatformat_ieee_single_little;
  92 extern const struct floatformat floatformat_ieee_double_big;
  93 extern const struct floatformat floatformat_ieee_double_little;
  94
  95 /* floatformat for ARM IEEE double, little endian bytes and big endian words */
  96
  97 extern const struct floatformat floatformat_ieee_double_littlebyte_bigword;
  98
  99 /* floatformats for various extendeds.  */
 100
 101 extern const struct floatformat floatformat_i387_ext;
 102 extern const struct floatformat floatformat_m68881_ext;
 103 extern const struct floatformat floatformat_i960_ext;
 104 extern const struct floatformat floatformat_m88110_ext;
 105 extern const struct floatformat floatformat_m88110_harris_ext;
 106 extern const struct floatformat floatformat_arm_ext_big;
 107 extern const struct floatformat floatformat_arm_ext_littlebyte_bigword;
 108 /* IA-64 Floating Point register spilt into memory.  */
 109 extern const struct floatformat floatformat_ia64_spill_big;
 110 extern const struct floatformat floatformat_ia64_spill_little;
 111 extern const struct floatformat floatformat_ia64_quad_big;
 112 extern const struct floatformat floatformat_ia64_quad_little;
 113
 114 /* Convert from FMT to a double.
 115    FROM is the address of the extended float.
 116    Store the double in *TO.  */
 117
 118 extern void
 119 floatformat_to_double (const struct floatformat *, const char *, double *);
 120
 121 /* The converse: convert the double *FROM to FMT
 122    and store where TO points.  */
 123
 124 extern void
 125 floatformat_from_double (const struct floatformat *, const double *, char *);
 126
 127 /* Return non-zero iff the data at FROM is a valid number in format FMT.  */
 128
 129 extern int
 130 floatformat_is_valid (const struct floatformat *fmt, const char *from);
 131
 132 #endif  /* defined (FLOATFORMAT_H) */