libdecnumber/decimal128.h

   1 /* Decimal 128-bit format module header for the decNumber C Library
   2    Copyright (C) 2005 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 #if !defined(DECIMAL128)
  23 #define DECIMAL128
  24 #define DEC128NAME     "decimal128"     /* Short name */
  25 #define DEC128FULLNAME "Decimal 128-bit Number" /* Verbose name */
  26 #define DEC128AUTHOR   "Mike Cowlishaw" /* Who to blame */
  27
  28 #if defined(DECIMAL32)
  29 #error decimal128.h must precede decimal32.h for correct DECNUMDIGITS
  30 #else
  31 #if defined(DECIMAL64)
  32 #error decimal128.h must precede decimal64.h for correct DECNUMDIGITS
  33 #endif
  34 #endif
  35
  36   /* parameters for decimal128s */
  37 #define DECIMAL128_Bytes  16    /* length */
  38 #define DECIMAL128_Pmax   34    /* maximum precision (digits) */
  39 #define DECIMAL128_Emax   6144  /* maximum adjusted exponent */
  40 #define DECIMAL128_Emin  -6143  /* minimum adjusted exponent */
  41 #define DECIMAL128_Bias   6176  /* bias for the exponent */
  42 #define DECIMAL128_String 43    /* maximum string length, +1 */
  43   /* highest biased exponent (Elimit-1) */
  44 #define DECIMAL128_Ehigh  (DECIMAL128_Emax+DECIMAL128_Bias-DECIMAL128_Pmax+1)
  45
  46 #ifndef DECNUMDIGITS
  47 #define DECNUMDIGITS DECIMAL128_Pmax    /* size if not already defined */
  48 #endif
  49 #ifndef DECNUMBER
  50 #include "decNumber.h"          /* context and number library */
  51 #endif
  52
  53   /* Decimal 128-bit type, accessible by bytes */
  54 typedef struct
  55 {
  56   uint8_t bytes[DECIMAL128_Bytes];      /* decimal128: 1, 5, 12, 110 bits */
  57 } decimal128;
  58
  59   /* special values [top byte excluding sign bit; last two bits are
  60      don't-care for Infinity on input, last bit don't-care for NaN] */
  61 #if !defined(DECIMAL_NaN)
  62 #define DECIMAL_NaN     0x7c    /* 0 11111 00 NaN */
  63 #define DECIMAL_sNaN    0x7e    /* 0 11111 10 sNaN */
  64 #define DECIMAL_Inf     0x78    /* 0 11110 00 Infinity */
  65 #endif
  66
  67   /* Macros for accessing decimal128 fields.  These assume the argument
  68      is a reference (pointer) to the decimal128 structure */
  69   /* Get sign */
  70 #define decimal128Sign(d)       ((unsigned)(d)->bytes[0]>>7)
  71
  72   /* Get combination field */
  73 #define decimal128Comb(d)       (((d)->bytes[0] & 0x7c)>>2)
  74
  75   /* Get exponent continuation [does not remove bias] */
  76 #define decimal128ExpCon(d)     ((((d)->bytes[0] & 0x03)<<10)       \
  77                                 | ((unsigned)(d)->bytes[1]<<2)        \
  78                                 | ((unsigned)(d)->bytes[2]>>6))
  79
  80   /* Set sign [this assumes sign previously 0] */
  81 #define decimal128SetSign(d, b) {                                   \
  82     (d)->bytes[0]|=((unsigned)(b)<<7);}
  83
  84   /* Set exponent continuation [does not apply bias] */
  85   /* This assumes range has been checked and exponent previously 0; */
  86   /* type of exponent must be unsigned */
  87 #define decimal128SetExpCon(d, e) {                                 \
  88     (d)->bytes[0]|=(uint8_t)((e)>>10);                                \
  89     (d)->bytes[1] =(uint8_t)(((e)&0x3fc)>>2);                         \
  90     (d)->bytes[2]|=(uint8_t)(((e)&0x03)<<6);}
  91
  92   /* ------------------------------------------------------------------ */
  93   /* Routines                                                           */
  94   /* ------------------------------------------------------------------ */
  95
  96 #ifdef IN_LIBGCC2
  97 #define decimal128FromString __decimal128FromString
  98 #define decimal128ToString __decimal128ToString
  99 #define decimal128ToEngString __decimal128ToEngString
 100 #define decimal128FromNumber __decimal128FromNumber
 101 #define decimal128ToNumber __decimal128ToNumber
 102 #endif
 103
 104   /* String conversions */
 105 decimal128 *decimal128FromString (decimal128 *, char *, decContext *);
 106 char *decimal128ToString (decimal128 *, char *);
 107 char *decimal128ToEngString (decimal128 *, char *);
 108
 109   /* decNumber conversions */
 110 decimal128 *decimal128FromNumber (decimal128 *, decNumber *, decContext *);
 111 decNumber *decimal128ToNumber (decimal128 *, decNumber *);
 112
 113 #endif