stdio-common/_i18n_itoa.c

   1 /* Internal function for converting integers to string using locale
   2    specific digits.
   3    Copyright (C) 2000 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Library General Public License as
   9    published by the Free Software Foundation; either version 2 of the
  10    License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Library General Public License for more details.
  16
  17    You should have received a copy of the GNU Library General Public
  18    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  19    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include <gmp-mparam.h>
  23 #include <stdlib/gmp.h>
  24 #include <stdlib/gmp-impl.h>
  25 #include <stdlib/longlong.h>
  26
  27 #include "_i18n_itoa.h"
  28
  29
  30 /* Canonize environment.  For some architectures not all values might
  31    be defined in the GMP header files.  */
  32 #ifndef UMUL_TIME
  33 # define UMUL_TIME 1
  34 #endif
  35 #ifndef UDIV_TIME
  36 # define UDIV_TIME 3
  37 #endif
  38
  39 /* Control memory layout.  */
  40 #ifdef PACK
  41 # undef PACK
  42 # define PACK __attribute__ ((packed))
  43 #else
  44 # define PACK
  45 #endif
  46
  47
  48 /* Declare local types.  */
  49 struct base_table_t
  50 {
  51 #if (UDIV_TIME > 2 * UMUL_TIME)
  52   mp_limb_t base_multiplier;
  53 #endif
  54   char flag;
  55   char post_shift;
  56 #if BITS_PER_MP_LIMB == 32
  57   struct
  58     {
  59       char normalization_steps;
  60       char ndigits;
  61       mp_limb_t base PACK;
  62 #if UDIV_TIME > 2 * UMUL_TIME
  63       mp_limb_t base_ninv PACK;
  64 #endif
  65     } big;
  66 #endif
  67 };
  68
  69
  70 /* Variable in other file.  */
  71 extern const struct base_table_t _itoa_base_table[];
  72
  73
  74 char *
  75 _i18n_itoa (value, buflim)
  76      unsigned long long int value;
  77      char *buflim;
  78 {
  79   const struct base_table_t *brec = &_itoa_base_table[8];
  80
  81 #if BITS_PER_MP_LIMB == 64
  82   mp_limb_t base_multiplier = brec->base_multiplier;
  83   if (brec->flag)    while (value != 0)
  84       {
  85         mp_limb_t quo, rem, x, dummy;
  86
  87         umul_ppmm (x, dummy, value, base_multiplier);
  88         quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
  89         rem = value - quo * 10;
  90         buflim = outdigit_value (buflim, rem);
  91         value = quo;
  92       }
  93   else
  94     while (value != 0)
  95       {
  96         mp_limb_t quo, rem, x, dummy;
  97
  98         umul_ppmm (x, dummy, value, base_multiplier);
  99         quo = x >> brec->post_shift;
 100         rem = value - quo * 10;
 101         buflim = outdigit_value (buflim, rem);
 102         value = quo;
 103       }
 104 #endif
 105 #if BITS_PER_MP_LIMB == 32
 106   mp_limb_t t[3];
 107   int n;
 108
 109   /* First convert x0 to 1-3 words in base s->big.base.
 110      Optimize for frequent cases of 32 bit numbers.  */
 111   if ((mp_limb_t) (value >> 32) >= 1)
 112     {
 113 #if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
 114       int big_normalization_steps = brec->big.normalization_steps;
 115       mp_limb_t big_base_norm
 116         = brec->big.base << big_normalization_steps;
 117 #endif
 118       if ((mp_limb_t) (value >> 32) >= brec->big.base)
 119         {
 120           mp_limb_t x1hi, x1lo, r;
 121           /* If you want to optimize this, take advantage of
 122              that the quotient in the first udiv_qrnnd will
 123              always be very small.  It might be faster just to
 124              subtract in a tight loop.  */
 125
 126 #if UDIV_TIME > 2 * UMUL_TIME
 127           mp_limb_t x, xh, xl;
 128
 129           if (big_normalization_steps == 0)
 130             xh = 0;
 131           else
 132             xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
 133           xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
 134           udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
 135                              brec->big.base_ninv);
 136
 137           xl = ((mp_limb_t) value) << big_normalization_steps;
 138           udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
 139                              brec->big.base_ninv);
 140           t[2] = x >> big_normalization_steps;
 141
 142           if (big_normalization_steps == 0)
 143             xh = x1hi;
 144           else
 145             xh = ((x1hi << big_normalization_steps)
 146                   | (x1lo >> (32 - big_normalization_steps)));
 147           xl = x1lo << big_normalization_steps;
 148           udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
 149                              brec->big.base_ninv);
 150           t[1] = x >> big_normalization_steps;
 151 #elif UDIV_NEEDS_NORMALIZATION
 152           mp_limb_t x, xh, xl;
 153
 154           if (big_normalization_steps == 0)
 155             xh = 0;
 156           else
 157             xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
 158           xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
 159           udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
 160
 161           xl = ((mp_limb_t) value) << big_normalization_steps;
 162           udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
 163           t[2] = x >> big_normalization_steps;
 164
 165           if (big_normalization_steps == 0)
 166             xh = x1hi;
 167           else
 168             xh = ((x1hi << big_normalization_steps)
 169                   | (x1lo >> 32 - big_normalization_steps));
 170           xl = x1lo << big_normalization_steps;
 171           udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
 172           t[1] = x >> big_normalization_steps;
 173 #else
 174           udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
 175                       brec->big.base);
 176           udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
 177           udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
 178 #endif
 179           n = 3;
 180         }
 181       else
 182         {
 183 #if (UDIV_TIME > 2 * UMUL_TIME)
 184           mp_limb_t x;
 185
 186           value <<= brec->big.normalization_steps;
 187           udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
 188                              (mp_limb_t) value, big_base_norm,
 189                              brec->big.base_ninv);
 190           t[1] = x >> brec->big.normalization_steps;
 191 #elif UDIV_NEEDS_NORMALIZATION
 192           mp_limb_t x;
 193
 194           value <<= big_normalization_steps;
 195           udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
 196                       (mp_limb_t) value, big_base_norm);
 197           t[1] = x >> big_normalization_steps;
 198 #else
 199           udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
 200                       (mp_limb_t) value, brec->big.base);
 201 #endif
 202           n = 2;
 203         }
 204     }
 205   else
 206     {
 207       t[0] = value;
 208       n = 1;
 209     }
 210
 211   /* Convert the 1-3 words in t[], word by word, to ASCII.  */
 212   do
 213     {
 214       mp_limb_t ti = t[--n];
 215       int ndig_for_this_limb = 0;
 216
 217 #if UDIV_TIME > 2 * UMUL_TIME
 218       mp_limb_t base_multiplier = brec->base_multiplier;
 219       if (brec->flag)
 220         while (ti != 0)
 221           {
 222             mp_limb_t quo, rem, x, dummy;
 223
 224             umul_ppmm (x, dummy, ti, base_multiplier);
 225             quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
 226             rem = ti - quo * 10;
 227             buflim = outdigit_value (buflim, rem);
 228             ti = quo;
 229             ++ndig_for_this_limb;
 230           }      else
 231         while (ti != 0)
 232           {
 233             mp_limb_t quo, rem, x, dummy;
 234
 235             umul_ppmm (x, dummy, ti, base_multiplier);
 236             quo = x >> brec->post_shift;
 237             rem = ti - quo * 10;
 238             buflim = outdigit_value (buflim, rem);
 239             ti = quo;
 240             ++ndig_for_this_limb;
 241           }
 242 #else
 243       while (ti != 0)
 244         {
 245           mp_limb_t quo, rem;
 246
 247           quo = ti / 10;
 248           rem = ti % 10;
 249           buflim = outdigit_value (buflim, rem);
 250           ti = quo;
 251           ++ndig_for_this_limb;
 252         }
 253 #endif
 254       /* If this wasn't the most significant word, pad with zeros.  */
 255       if (n != 0)
 256         while (ndig_for_this_limb < brec->big.ndigits)
 257           {
 258             *--buflim = '0';
 259             ++ndig_for_this_limb;
 260           }
 261     }
 262   while (n != 0);
 263 #endif
 264
 265   return buflim;
 266 }