libdecnumber/decContext.h

   1 /* Decimal context header module for the decNumber C Library.
   2    Copyright (C) 2005, 2007, 2009 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 3, 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 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 /* ------------------------------------------------------------------ */
  27 /* Decimal Context module header                                      */
  28 /* ------------------------------------------------------------------ */
  29 /*                                                                    */
  30 /* Context variables must always have valid values:                   */
  31 /*                                                                    */
  32 /*  status   -- [any bits may be cleared, but not set, by user]       */
  33 /*  round    -- must be one of the enumerated rounding modes          */
  34 /*                                                                    */
  35 /* The following variables are implied for fixed size formats (i.e.,  */
  36 /* they are ignored) but should still be set correctly in case used   */
  37 /* with decNumber functions:                                          */
  38 /*                                                                    */
  39 /*  clamp    -- must be either 0 or 1                                 */
  40 /*  digits   -- must be in the range 1 through 999999999              */
  41 /*  emax     -- must be in the range 0 through 999999999              */
  42 /*  emin     -- must be in the range 0 through -999999999             */
  43 /*  extended -- must be either 0 or 1 [present only if DECSUBSET]     */
  44 /*  traps    -- only defined bits may be set                          */
  45 /*                                                                    */
  46 /* ------------------------------------------------------------------ */
  47
  48 #if !defined(DECCONTEXT)
  49   #define DECCONTEXT
  50   #define DECCNAME     "decContext"                     /* Short name */
  51   #define DECCFULLNAME "Decimal Context Descriptor"   /* Verbose name */
  52   #define DECCAUTHOR   "Mike Cowlishaw"               /* Who to blame */
  53
  54   #include "gstdint.h"             /* C99 standard integers           */
  55   #include <stdio.h>               /* for printf, etc.                */
  56   #include <signal.h>              /* for traps                       */
  57
  58   /* Extended flags setting -- set this to 0 to use only IEEE flags   */
  59   #if !defined(DECEXTFLAG)
  60   #define DECEXTFLAG 1             /* 1=enable extended flags         */
  61   #endif
  62
  63   /* Conditional code flag -- set this to 0 for best performance      */
  64   #if !defined(DECSUBSET)
  65   #define DECSUBSET  0             /* 1=enable subset arithmetic      */
  66   #endif
  67
  68   /* Context for operations, with associated constants                */
  69   enum rounding {
  70     DEC_ROUND_CEILING,             /* round towards +infinity         */
  71     DEC_ROUND_UP,                  /* round away from 0               */
  72     DEC_ROUND_HALF_UP,             /* 0.5 rounds up                   */
  73     DEC_ROUND_HALF_EVEN,           /* 0.5 rounds to nearest even      */
  74     DEC_ROUND_HALF_DOWN,           /* 0.5 rounds down                 */
  75     DEC_ROUND_DOWN,                /* round towards 0 (truncate)      */
  76     DEC_ROUND_FLOOR,               /* round towards -infinity         */
  77     DEC_ROUND_05UP,                /* round for reround               */
  78     DEC_ROUND_MAX                  /* enum must be less than this     */
  79     };
  80   #define DEC_ROUND_DEFAULT DEC_ROUND_HALF_EVEN;
  81
  82   typedef struct {
  83     int32_t  digits;               /* working precision               */
  84     int32_t  emax;                 /* maximum positive exponent       */
  85     int32_t  emin;                 /* minimum negative exponent       */
  86     enum     rounding round;       /* rounding mode                   */
  87     uint32_t traps;                /* trap-enabler flags              */
  88     uint32_t status;               /* status flags                    */
  89     uint8_t  clamp;                /* flag: apply IEEE exponent clamp */
  90     #if DECSUBSET
  91     uint8_t  extended;             /* flag: special-values allowed    */
  92     #endif
  93     } decContext;
  94
  95   /* Maxima and Minima for context settings                           */
  96   #define DEC_MAX_DIGITS 999999999
  97   #define DEC_MIN_DIGITS         1
  98   #define DEC_MAX_EMAX   999999999
  99   #define DEC_MIN_EMAX           0
 100   #define DEC_MAX_EMIN           0
 101   #define DEC_MIN_EMIN  -999999999
 102   #define DEC_MAX_MATH      999999 /* max emax, etc., for math funcs. */
 103
 104   /* Classifications for decimal numbers, aligned with 754 (note that */
 105   /* 'normal' and 'subnormal' are meaningful only with a decContext   */
 106   /* or a fixed size format).                                         */
 107   enum decClass {
 108     DEC_CLASS_SNAN,
 109     DEC_CLASS_QNAN,
 110     DEC_CLASS_NEG_INF,
 111     DEC_CLASS_NEG_NORMAL,
 112     DEC_CLASS_NEG_SUBNORMAL,
 113     DEC_CLASS_NEG_ZERO,
 114     DEC_CLASS_POS_ZERO,
 115     DEC_CLASS_POS_SUBNORMAL,
 116     DEC_CLASS_POS_NORMAL,
 117     DEC_CLASS_POS_INF
 118     };
 119   /* Strings for the decClasses */
 120   #define DEC_ClassString_SN  "sNaN"
 121   #define DEC_ClassString_QN  "NaN"
 122   #define DEC_ClassString_NI  "-Infinity"
 123   #define DEC_ClassString_NN  "-Normal"
 124   #define DEC_ClassString_NS  "-Subnormal"
 125   #define DEC_ClassString_NZ  "-Zero"
 126   #define DEC_ClassString_PZ  "+Zero"
 127   #define DEC_ClassString_PS  "+Subnormal"
 128   #define DEC_ClassString_PN  "+Normal"
 129   #define DEC_ClassString_PI  "+Infinity"
 130   #define DEC_ClassString_UN  "Invalid"
 131
 132   /* Trap-enabler and Status flags (exceptional conditions), and      */
 133   /* their names.  The top byte is reserved for internal use          */
 134   #if DECEXTFLAG
 135     /* Extended flags */
 136     #define DEC_Conversion_syntax    0x00000001
 137     #define DEC_Division_by_zero     0x00000002
 138     #define DEC_Division_impossible  0x00000004
 139     #define DEC_Division_undefined   0x00000008
 140     #define DEC_Insufficient_storage 0x00000010 /* [when malloc fails]  */
 141     #define DEC_Inexact              0x00000020
 142     #define DEC_Invalid_context      0x00000040
 143     #define DEC_Invalid_operation    0x00000080
 144     #if DECSUBSET
 145     #define DEC_Lost_digits          0x00000100
 146     #endif
 147     #define DEC_Overflow             0x00000200
 148     #define DEC_Clamped              0x00000400
 149     #define DEC_Rounded              0x00000800
 150     #define DEC_Subnormal            0x00001000
 151     #define DEC_Underflow            0x00002000
 152   #else
 153     /* IEEE flags only */
 154     #define DEC_Conversion_syntax    0x00000010
 155     #define DEC_Division_by_zero     0x00000002
 156     #define DEC_Division_impossible  0x00000010
 157     #define DEC_Division_undefined   0x00000010
 158     #define DEC_Insufficient_storage 0x00000010 /* [when malloc fails]  */
 159     #define DEC_Inexact              0x00000001
 160     #define DEC_Invalid_context      0x00000010
 161     #define DEC_Invalid_operation    0x00000010
 162     #if DECSUBSET
 163     #define DEC_Lost_digits          0x00000000
 164     #endif
 165     #define DEC_Overflow             0x00000008
 166     #define DEC_Clamped              0x00000000
 167     #define DEC_Rounded              0x00000000
 168     #define DEC_Subnormal            0x00000000
 169     #define DEC_Underflow            0x00000004
 170   #endif
 171
 172   /* IEEE 754 groupings for the flags                                 */
 173   /* [DEC_Clamped, DEC_Lost_digits, DEC_Rounded, and DEC_Subnormal    */
 174   /* are not in IEEE 754]                                             */
 175   #define DEC_IEEE_754_Division_by_zero  (DEC_Division_by_zero)
 176   #if DECSUBSET
 177   #define DEC_IEEE_754_Inexact           (DEC_Inexact | DEC_Lost_digits)
 178   #else
 179   #define DEC_IEEE_754_Inexact           (DEC_Inexact)
 180   #endif
 181   #define DEC_IEEE_754_Invalid_operation (DEC_Conversion_syntax |     \
 182                                           DEC_Division_impossible |   \
 183                                           DEC_Division_undefined |    \
 184                                           DEC_Insufficient_storage |  \
 185                                           DEC_Invalid_context |       \
 186                                           DEC_Invalid_operation)
 187   #define DEC_IEEE_754_Overflow          (DEC_Overflow)
 188   #define DEC_IEEE_754_Underflow         (DEC_Underflow)
 189
 190   /* flags which are normally errors (result is qNaN, infinite, or 0) */
 191   #define DEC_Errors (DEC_IEEE_754_Division_by_zero |                 \
 192                       DEC_IEEE_754_Invalid_operation |                \
 193                       DEC_IEEE_754_Overflow | DEC_IEEE_754_Underflow)
 194   /* flags which cause a result to become qNaN                        */
 195   #define DEC_NaNs    DEC_IEEE_754_Invalid_operation
 196
 197   /* flags which are normally for information only (finite results)   */
 198   #if DECSUBSET
 199   #define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact    \
 200                           | DEC_Lost_digits)
 201   #else
 202   #define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact)
 203   #endif
 204
 205   /* IEEE 854 names (for compatibility with older decNumber versions) */
 206   #define DEC_IEEE_854_Division_by_zero  DEC_IEEE_754_Division_by_zero
 207   #define DEC_IEEE_854_Inexact           DEC_IEEE_754_Inexact
 208   #define DEC_IEEE_854_Invalid_operation DEC_IEEE_754_Invalid_operation
 209   #define DEC_IEEE_854_Overflow          DEC_IEEE_754_Overflow
 210   #define DEC_IEEE_854_Underflow         DEC_IEEE_754_Underflow
 211
 212   /* Name strings for the exceptional conditions                      */
 213   #define DEC_Condition_CS "Conversion syntax"
 214   #define DEC_Condition_DZ "Division by zero"
 215   #define DEC_Condition_DI "Division impossible"
 216   #define DEC_Condition_DU "Division undefined"
 217   #define DEC_Condition_IE "Inexact"
 218   #define DEC_Condition_IS "Insufficient storage"
 219   #define DEC_Condition_IC "Invalid context"
 220   #define DEC_Condition_IO "Invalid operation"
 221   #if DECSUBSET
 222   #define DEC_Condition_LD "Lost digits"
 223   #endif
 224   #define DEC_Condition_OV "Overflow"
 225   #define DEC_Condition_PA "Clamped"
 226   #define DEC_Condition_RO "Rounded"
 227   #define DEC_Condition_SU "Subnormal"
 228   #define DEC_Condition_UN "Underflow"
 229   #define DEC_Condition_ZE "No status"
 230   #define DEC_Condition_MU "Multiple status"
 231   #define DEC_Condition_Length 21  /* length of the longest string,   */
 232                                    /* including terminator            */
 233
 234   /* Initialization descriptors, used by decContextDefault            */
 235   #define DEC_INIT_BASE         0
 236   #define DEC_INIT_DECIMAL32   32
 237   #define DEC_INIT_DECIMAL64   64
 238   #define DEC_INIT_DECIMAL128 128
 239   /* Synonyms */
 240   #define DEC_INIT_DECSINGLE  DEC_INIT_DECIMAL32
 241   #define DEC_INIT_DECDOUBLE  DEC_INIT_DECIMAL64
 242   #define DEC_INIT_DECQUAD    DEC_INIT_DECIMAL128
 243
 244   /* decContext routines                                              */
 245
 246   #include "decContextSymbols.h"
 247
 248   #ifdef __cplusplus
 249   extern "C" {
 250   #endif
 251
 252   extern decContext  * decContextClearStatus(decContext *, uint32_t);
 253   extern decContext  * decContextDefault(decContext *, int32_t);
 254   extern enum rounding decContextGetRounding(decContext *);
 255   extern uint32_t      decContextGetStatus(decContext *);
 256   extern decContext  * decContextRestoreStatus(decContext *, uint32_t, uint32_t);
 257   extern uint32_t      decContextSaveStatus(decContext *, uint32_t);
 258   extern decContext  * decContextSetRounding(decContext *, enum rounding);
 259   extern decContext  * decContextSetStatus(decContext *, uint32_t);
 260   extern decContext  * decContextSetStatusFromString(decContext *, const char *);
 261   extern decContext  * decContextSetStatusFromStringQuiet(decContext *, const char *);
 262   extern decContext  * decContextSetStatusQuiet(decContext *, uint32_t);
 263   extern const char  * decContextStatusToString(const decContext *);
 264   extern int32_t       decContextTestEndian(uint8_t);
 265   extern uint32_t      decContextTestSavedStatus(uint32_t, uint32_t);
 266   extern uint32_t      decContextTestStatus(decContext *, uint32_t);
 267   extern decContext  * decContextZeroStatus(decContext *);
 268
 269   #ifdef __cplusplus
 270   }
 271   #endif
 272
 273 #endif