libdecnumber/decContext.h

   1 /* Decimal Context module header for the decNumber C Library
   2    Copyright (C) 2005, 2006 Free Software Foundation, Inc.
   3    Contributed by IBM Corporation.  Author Mike Cowlishaw.
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify it under
   8    the terms of the GNU General Public License as published by the Free
   9    Software Foundation; either version 2, or (at your option) any later
  10    version.
  11
  12    GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13    WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15    for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 /* ------------------------------------------------------------------ */
  23 /*                                                                    */
  24 /* Context must always be set correctly:                              */
  25 /*                                                                    */
  26 /*  digits   -- must be in the range 1 through 999999999              */
  27 /*  emax     -- must be in the range 0 through 999999999              */
  28 /*  emin     -- must be in the range 0 through -999999999             */
  29 /*  round    -- must be one of the enumerated rounding modes          */
  30 /*  traps    -- only defined bits may be set                          */
  31 /*  status   -- [any bits may be cleared, but not set, by user]       */
  32 /*  clamp    -- must be either 0 or 1                                 */
  33 /*  extended -- must be either 0 or 1 [present only if DECSUBSET]     */
  34 /*                                                                    */
  35 /* ------------------------------------------------------------------ */
  36
  37 #if !defined(DECCONTEXT)
  38 #define DECCONTEXT
  39 #define DECCNAME     "decContext"       /* Short name */
  40 #define DECCFULLNAME "Decimal Context Descriptor"       /* Verbose name */
  41 #define DECCAUTHOR   "Mike Cowlishaw"   /* Who to blame */
  42
  43 #include "gstdint.h"            /* C99 standard integers */
  44 #include <signal.h>             /* for traps */
  45
  46
  47   /* Conditional code flag -- set this to 0 for best performance */
  48 #define DECSUBSET 0             /* 1 to enable subset arithmetic */
  49
  50   /* Context for operations, with associated constants */
  51 enum rounding
  52 {
  53   DEC_ROUND_CEILING,            /* round towards +infinity */
  54   DEC_ROUND_UP,                 /* round away from 0 */
  55   DEC_ROUND_HALF_UP,            /* 0.5 rounds up */
  56   DEC_ROUND_HALF_EVEN,          /* 0.5 rounds to nearest even */
  57   DEC_ROUND_HALF_DOWN,          /* 0.5 rounds down */
  58   DEC_ROUND_DOWN,               /* round towards 0 (truncate) */
  59   DEC_ROUND_FLOOR,              /* round towards -infinity */
  60   DEC_ROUND_MAX                 /* enum must be less than this */
  61 };
  62
  63 typedef struct
  64 {
  65   int32_t digits;               /* working precision */
  66   int32_t emax;                 /* maximum positive exponent */
  67   int32_t emin;                 /* minimum negative exponent */
  68   enum rounding round;          /* rounding mode */
  69   uint32_t traps;               /* trap-enabler flags */
  70   uint32_t status;              /* status flags */
  71   uint8_t clamp;                /* flag: apply IEEE exponent clamp */
  72 #if DECSUBSET
  73   uint8_t extended;             /* flag: special-values allowed */
  74 #endif
  75 } decContext;
  76
  77   /* Maxima and Minima */
  78 #define DEC_MAX_DIGITS 999999999
  79 #define DEC_MIN_DIGITS         1
  80 #define DEC_MAX_EMAX   999999999
  81 #define DEC_MIN_EMAX           0
  82 #define DEC_MAX_EMIN           0
  83 #define DEC_MIN_EMIN  -999999999
  84
  85   /* Trap-enabler and Status flags (exceptional conditions), and their names */
  86   /* Top byte is reserved for internal use */
  87 #define DEC_Conversion_syntax    0x00000001
  88 #define DEC_Division_by_zero     0x00000002
  89 #define DEC_Division_impossible  0x00000004
  90 #define DEC_Division_undefined   0x00000008
  91 #define DEC_Insufficient_storage 0x00000010     /* [used if malloc fails] */
  92 #define DEC_Inexact              0x00000020
  93 #define DEC_Invalid_context      0x00000040
  94 #define DEC_Invalid_operation    0x00000080
  95 #if DECSUBSET
  96 #define DEC_Lost_digits          0x00000100
  97 #endif
  98 #define DEC_Overflow             0x00000200
  99 #define DEC_Clamped              0x00000400
 100 #define DEC_Rounded              0x00000800
 101 #define DEC_Subnormal            0x00001000
 102 #define DEC_Underflow            0x00002000
 103
 104   /* IEEE 854 groupings for the flags */
 105   /* [DEC_Clamped, DEC_Lost_digits, DEC_Rounded, and DEC_Subnormal are */
 106   /* not in IEEE 854] */
 107 #define DEC_IEEE_854_Division_by_zero  (DEC_Division_by_zero)
 108 #if DECSUBSET
 109 #define DEC_IEEE_854_Inexact           (DEC_Inexact | DEC_Lost_digits)
 110 #else
 111 #define DEC_IEEE_854_Inexact           (DEC_Inexact)
 112 #endif
 113 #define DEC_IEEE_854_Invalid_operation (DEC_Conversion_syntax |     \
 114                                           DEC_Division_impossible |   \
 115                                           DEC_Division_undefined |    \
 116                                           DEC_Insufficient_storage |  \
 117                                           DEC_Invalid_context |       \
 118                                           DEC_Invalid_operation)
 119 #define DEC_IEEE_854_Overflow          (DEC_Overflow)
 120 #define DEC_IEEE_854_Underflow         (DEC_Underflow)
 121
 122   /* flags which are normally errors (results are qNaN, infinite, or 0) */
 123 #define DEC_Errors (DEC_IEEE_854_Division_by_zero |                 \
 124                       DEC_IEEE_854_Invalid_operation |                \
 125                       DEC_IEEE_854_Overflow | DEC_IEEE_854_Underflow)
 126   /* flags which cause a result to become qNaN */
 127 #define DEC_NaNs    DEC_IEEE_854_Invalid_operation
 128
 129   /* flags which are normally for information only (have finite results) */
 130 #if DECSUBSET
 131 #define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact     \
 132                           | DEC_Lost_digits)
 133 #else
 134 #define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact)
 135 #endif
 136
 137   /* name strings for the exceptional conditions */
 138
 139 #define DEC_Condition_CS "Conversion syntax"
 140 #define DEC_Condition_DZ "Division by zero"
 141 #define DEC_Condition_DI "Division impossible"
 142 #define DEC_Condition_DU "Division undefined"
 143 #define DEC_Condition_IE "Inexact"
 144 #define DEC_Condition_IS "Insufficient storage"
 145 #define DEC_Condition_IC "Invalid context"
 146 #define DEC_Condition_IO "Invalid operation"
 147 #if DECSUBSET
 148 #define DEC_Condition_LD "Lost digits"
 149 #endif
 150 #define DEC_Condition_OV "Overflow"
 151 #define DEC_Condition_PA "Clamped"
 152 #define DEC_Condition_RO "Rounded"
 153 #define DEC_Condition_SU "Subnormal"
 154 #define DEC_Condition_UN "Underflow"
 155 #define DEC_Condition_ZE "No status"
 156 #define DEC_Condition_MU "Multiple status"
 157 #define DEC_Condition_Length 21 /* length of the longest string, */
 158                                    /* including terminator */
 159
 160   /* Initialization descriptors, used by decContextDefault */
 161 #define DEC_INIT_BASE         0
 162 #define DEC_INIT_DECIMAL32   32
 163 #define DEC_INIT_DECIMAL64   64
 164 #define DEC_INIT_DECIMAL128 128
 165
 166   /* decContext routines */
 167 #ifdef IN_LIBGCC2
 168 #define decContextDefault __decContextDefault
 169 #define decContextSetStatus __decContextSetStatus
 170 #define decContextStatusToString __decContextStatusToString
 171 #define decContextSetStatusFromString __decContextSetStatusFromString
 172 #endif
 173 decContext *decContextDefault (decContext *, int32_t);
 174 decContext *decContextSetStatus (decContext *, uint32_t);
 175 const char *decContextStatusToString (const decContext *);
 176 decContext *decContextSetStatusFromString (decContext *, const char *);
 177
 178 #endif