decContext.h   [plain text]

/* Decimal Context module header for the decNumber C Library
   Copyright (C) 2005, 2006 Free Software Foundation, Inc.
   Contributed by IBM Corporation.  Author Mike Cowlishaw.

   This file is part of GCC.

   GCC is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free
   Software Foundation; either version 2, or (at your option) any later
   version.

   In addition to the permissions in the GNU General Public License,
   the Free Software Foundation gives you unlimited permission to link
   the compiled version of this file into combinations with other
   programs, and to distribute those combinations without any
   restriction coming from the use of this file.  (The General Public
   License restrictions do apply in other respects; for example, they
   cover modification of the file, and distribution when not linked
   into a combine executable.)

   GCC is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or
   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   for more details.

   You should have received a copy of the GNU General Public License
   along with GCC; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.  */

/* ------------------------------------------------------------------ */
/*                                                                    */
/* Context must always be set correctly:                              */
/*                                                                    */
/*  digits   -- must be in the range 1 through 999999999              */
/*  emax     -- must be in the range 0 through 999999999              */
/*  emin     -- must be in the range 0 through -999999999             */
/*  round    -- must be one of the enumerated rounding modes          */
/*  traps    -- only defined bits may be set                          */
/*  status   -- [any bits may be cleared, but not set, by user]       */
/*  clamp    -- must be either 0 or 1                                 */
/*  extended -- must be either 0 or 1 [present only if DECSUBSET]     */
/*                                                                    */
/* ------------------------------------------------------------------ */

#if !defined(DECCONTEXT)
#define DECCONTEXT
#define DECCNAME     "decContext"	/* Short name */
#define DECCFULLNAME "Decimal Context Descriptor"	/* Verbose name */
#define DECCAUTHOR   "Mike Cowlishaw"	/* Who to blame */

#include "gstdint.h"		/* C99 standard integers */
#include <signal.h>		/* for traps */


  /* Conditional code flag -- set this to 0 for best performance */
#define DECSUBSET 0		/* 1 to enable subset arithmetic */

  /* Context for operations, with associated constants */
enum rounding
{
  DEC_ROUND_CEILING,		/* round towards +infinity */
  DEC_ROUND_UP,			/* round away from 0 */
  DEC_ROUND_HALF_UP,		/* 0.5 rounds up */
  DEC_ROUND_HALF_EVEN,		/* 0.5 rounds to nearest even */
  DEC_ROUND_HALF_DOWN,		/* 0.5 rounds down */
  DEC_ROUND_DOWN,		/* round towards 0 (truncate) */
  DEC_ROUND_FLOOR,		/* round towards -infinity */
  DEC_ROUND_MAX			/* enum must be less than this */
};

typedef struct
{
  int32_t digits;		/* working precision */
  int32_t emax;			/* maximum positive exponent */
  int32_t emin;			/* minimum negative exponent */
  enum rounding round;		/* rounding mode */
  uint32_t traps;		/* trap-enabler flags */
  uint32_t status;		/* status flags */
  uint8_t clamp;		/* flag: apply IEEE exponent clamp */
#if DECSUBSET
  uint8_t extended;		/* flag: special-values allowed */
#endif
} decContext;

  /* Maxima and Minima */
#define DEC_MAX_DIGITS 999999999
#define DEC_MIN_DIGITS         1
#define DEC_MAX_EMAX   999999999
#define DEC_MIN_EMAX           0
#define DEC_MAX_EMIN           0
#define DEC_MIN_EMIN  -999999999

  /* Trap-enabler and Status flags (exceptional conditions), and their names */
  /* Top byte is reserved for internal use */
#define DEC_Conversion_syntax    0x00000001
#define DEC_Division_by_zero     0x00000002
#define DEC_Division_impossible  0x00000004
#define DEC_Division_undefined   0x00000008
#define DEC_Insufficient_storage 0x00000010	/* [used if malloc fails] */
#define DEC_Inexact              0x00000020
#define DEC_Invalid_context      0x00000040
#define DEC_Invalid_operation    0x00000080
#if DECSUBSET
#define DEC_Lost_digits          0x00000100
#endif
#define DEC_Overflow             0x00000200
#define DEC_Clamped              0x00000400
#define DEC_Rounded              0x00000800
#define DEC_Subnormal            0x00001000
#define DEC_Underflow            0x00002000

  /* IEEE 854 groupings for the flags */
  /* [DEC_Clamped, DEC_Lost_digits, DEC_Rounded, and DEC_Subnormal are */
  /* not in IEEE 854] */
#define DEC_IEEE_854_Division_by_zero  (DEC_Division_by_zero)
#if DECSUBSET
#define DEC_IEEE_854_Inexact           (DEC_Inexact | DEC_Lost_digits)
#else
#define DEC_IEEE_854_Inexact           (DEC_Inexact)
#endif
#define DEC_IEEE_854_Invalid_operation (DEC_Conversion_syntax |     \
                                          DEC_Division_impossible |   \
                                          DEC_Division_undefined |    \
                                          DEC_Insufficient_storage |  \
                                          DEC_Invalid_context |       \
                                          DEC_Invalid_operation)
#define DEC_IEEE_854_Overflow          (DEC_Overflow)
#define DEC_IEEE_854_Underflow         (DEC_Underflow)

  /* flags which are normally errors (results are qNaN, infinite, or 0) */
#define DEC_Errors (DEC_IEEE_854_Division_by_zero |                 \
                      DEC_IEEE_854_Invalid_operation |                \
                      DEC_IEEE_854_Overflow | DEC_IEEE_854_Underflow)
  /* flags which cause a result to become qNaN */
#define DEC_NaNs    DEC_IEEE_854_Invalid_operation

  /* flags which are normally for information only (have finite results) */
#if DECSUBSET
#define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact     \
                          | DEC_Lost_digits)
#else
#define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact)
#endif

  /* name strings for the exceptional conditions */

#define DEC_Condition_CS "Conversion syntax"
#define DEC_Condition_DZ "Division by zero"
#define DEC_Condition_DI "Division impossible"
#define DEC_Condition_DU "Division undefined"
#define DEC_Condition_IE "Inexact"
#define DEC_Condition_IS "Insufficient storage"
#define DEC_Condition_IC "Invalid context"
#define DEC_Condition_IO "Invalid operation"
#if DECSUBSET
#define DEC_Condition_LD "Lost digits"
#endif
#define DEC_Condition_OV "Overflow"
#define DEC_Condition_PA "Clamped"
#define DEC_Condition_RO "Rounded"
#define DEC_Condition_SU "Subnormal"
#define DEC_Condition_UN "Underflow"
#define DEC_Condition_ZE "No status"
#define DEC_Condition_MU "Multiple status"
#define DEC_Condition_Length 21	/* length of the longest string, */
				   /* including terminator */

  /* Initialization descriptors, used by decContextDefault */
#define DEC_INIT_BASE         0
#define DEC_INIT_DECIMAL32   32
#define DEC_INIT_DECIMAL64   64
#define DEC_INIT_DECIMAL128 128

  /* decContext routines */
#ifdef IN_LIBGCC2
#define decContextDefault __decContextDefault
#define decContextSetStatus __decContextSetStatus
#define decContextStatusToString __decContextStatusToString
#define decContextSetStatusFromString __decContextSetStatusFromString
#endif
decContext *decContextDefault (decContext *, int32_t);
decContext *decContextSetStatus (decContext *, uint32_t);
const char *decContextStatusToString (const decContext *);
decContext *decContextSetStatusFromString (decContext *, const char *);

#endif