src/decNumber/decimal64.h

/* */
   1 // vim: filetype=c:tabstop=4:ai:expandtab
   2 // SPDX-License-Identifier: ICU
   3 // scspell-id: be530c08-f62c-11ec-8642-80ee73e9b8e7
   4 /* ------------------------------------------------------------------- */
   5 /* Decimal 64-bit format module header                                 */
   6 /* ------------------------------------------------------------------- */
   7 /*                                                                     */
   8 /* Copyright (c) IBM Corporation, 2000, 2005.  All rights reserved.    */
   9 /*                                                                     */
  10 /* This software is made available under the terms of the ICU License. */
  11 /*                                                                     */
  12 /* The description and User's Guide ("The decNumber C Library") for    */
  13 /* this software is called decNumber.pdf.  This document is available, */
  14 /* together with arithmetic and format specifications, testcases, and  */
  15 /* Web links, on the General Decimal Arithmetic page.                  */
  16 /*                                                                     */
  17 /* Please send comments, suggestions, and corrections to the author:   */
  18 /*   mfc@uk.ibm.com                                                    */
  19 /*   Mike Cowlishaw, IBM Fellow                                        */
  20 /*   IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK          */
  21 /*                                                                     */
  22 /* ------------------------------------------------------------------- */
  23 
  24 #if !defined(DECIMAL64)
  25 # define DECIMAL64
  26 # define DEC64NAME     "decimal64"                    /* Short name   */
  27 # define DEC64FULLNAME "Decimal 64-bit Number"        /* Verbose name */
  28 # define DEC64AUTHOR   "Mike Cowlishaw"               /* Who to blame */
  29 
  30   /* parameters for decimal64s */
  31 # define DECIMAL64_Bytes  8             /* length                     */
  32 # define DECIMAL64_Pmax   16            /* maximum precision (digits) */
  33 # define DECIMAL64_Emax   384           /* maximum adjusted exponent  */
  34 # define DECIMAL64_Emin  -383           /* minimum adjusted exponent  */
  35 # define DECIMAL64_Bias   398           /* bias for the exponent      */
  36 # define DECIMAL64_String 24            /* maximum string length, +1  */
  37 # define DECIMAL64_EconL  8             /* exp. continuation length   */
  38   /* highest biased exponent (Elimit-1)                               */
  39 # define DECIMAL64_Ehigh                                               \
  40     (DECIMAL64_Emax+DECIMAL64_Bias-DECIMAL64_Pmax+1)
  41 
  42   /* check enough digits, if pre-defined                              */
  43 # if defined(DECNUMDIGITS)
  44 #  if (DECNUMDIGITS<DECIMAL64_Pmax)
  45 #   error decimal64.h needs pre-defined DECNUMDIGITS>=16 for safe use
  46 #  endif
  47 # endif
  48 
  49 # if !defined(DECNUMDIGITS)
  50 #  define DECNUMDIGITS DECIMAL64_Pmax  /* size if not already defined */
  51 # endif /* if !defined(DECNUMDIGITS) */
  52 # if !defined(DECNUMBER)
  53 #  include "decNumber.h"                /* context and number library */
  54 # endif /* if !defined(DECNUMBER) */
  55 
  56   /* Decimal 64-bit type, accessible by bytes                         */
  57   typedef struct {
  58     uint8_t bytes[DECIMAL64_Bytes];    /* decimal64: 1, 5, 8, 50 bits */
  59     } decimal64;
  60 
  61   /* special values [top byte excluding sign bit; last two bits are   */
  62   /* don't-care for Infinity on input, last bit don't-care for NaN]   */
  63 # if !defined(DECIMAL_NaN)
  64 #  define DECIMAL_NaN     0x7c         /* 0 11111 00 NaN              */
  65 #  define DECIMAL_sNaN    0x7e         /* 0 11111 10 sNaN             */
  66 #  define DECIMAL_Inf     0x78         /* 0 11110 00 Infinity         */
  67 # endif
  68 
  69   /* ---------------------------------------------------------------- */
  70   /* Routines                                                         */
  71   /* ---------------------------------------------------------------- */
  72   /* String conversions                                               */
  73   decimal64 * decimal64FromString(decimal64 *, const char *,
  74     decContext *);
  75   char * decimal64ToString(const decimal64 *, char *);
  76   char * decimal64ToEngString(const decimal64 *, char *);
  77 
  78   /* decNumber conversions                                            */
  79   decimal64 * decimal64FromNumber(decimal64 *, const decNumber *,
  80                                   decContext *);
  81   decNumber * decimal64ToNumber(const decimal64 *, decNumber *);
  82 
  83   /* Format-dependent utilities                                       */
  84   uint32_t    decimal64IsCanonical(const decimal64 *);
  85   decimal64 * decimal64Canonical(decimal64 *, const decimal64 *);
  86 
  87 #endif
/* */
root/src/decNumber/decimal64.h
