stdio-common/_itowa.c

   1 /* Internal function for converting integers to ASCII.
   2    Copyright (C) 1994-1996,1999,2000,2002,2007 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Torbjorn Granlund <tege@matematik.su.se>
   5    and Ulrich Drepper <drepper@gnu.org>.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the 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    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #include <gmp-mparam.h>
  23 #include <gmp.h>
  24 #include <limits.h>
  25 #include <stdlib/gmp-impl.h>
  26 #include <stdlib/longlong.h>
  27
  28 #include "_itowa.h"
  29
  30
  31 /* Canonize environment.  For some architectures not all values might
  32    be defined in the GMP header files.  */
  33 #ifndef UMUL_TIME
  34 # define UMUL_TIME 1
  35 #endif
  36 #ifndef UDIV_TIME
  37 # define UDIV_TIME 3
  38 #endif
  39
  40 /* Control memory layout.  */
  41 #ifdef PACK
  42 # undef PACK
  43 # define PACK __attribute__ ((packed))
  44 #else
  45 # define PACK
  46 #endif
  47
  48
  49 /* Declare local types.  */
  50 struct base_table_t
  51 {
  52 #if (UDIV_TIME > 2 * UMUL_TIME)
  53   mp_limb_t base_multiplier;
  54 #endif
  55   char flag;
  56   char post_shift;
  57 #if BITS_PER_MP_LIMB == 32
  58   struct
  59     {
  60       char normalization_steps;
  61       char ndigits;
  62       mp_limb_t base PACK;
  63 #if UDIV_TIME > 2 * UMUL_TIME
  64       mp_limb_t base_ninv PACK;
  65 #endif
  66     } big;
  67 #endif
  68 };
  69
  70 /* To reduce the memory needed we include some fields of the tables
  71    only conditionally.  */
  72 #if UDIV_TIME > 2 * UMUL_TIME
  73 # define SEL1(X) X,
  74 # define SEL2(X) ,X
  75 #else
  76 # define SEL1(X)
  77 # define SEL2(X)
  78 #endif
  79
  80 /* Factor table for the different bases.  */
  81 extern const struct base_table_t _itoa_base_table[] attribute_hidden;
  82
  83 /* Lower-case digits.  */
  84 extern const wchar_t _itowa_lower_digits[] attribute_hidden;
  85 /* Upper-case digits.  */
  86 extern const wchar_t _itowa_upper_digits[] attribute_hidden;
  87
  88
  89 #if LLONG_MAX != LONG_MAX
  90 wchar_t *
  91 _itowa (value, buflim, base, upper_case)
  92      unsigned long long int value;
  93      wchar_t *buflim;
  94      unsigned int base;
  95      int upper_case;
  96 {
  97   const wchar_t *digits = (upper_case
  98                            ? _itowa_upper_digits : _itowa_lower_digits);
  99   wchar_t *bp = buflim;
 100   const struct base_table_t *brec = &_itoa_base_table[base - 2];
 101
 102   switch (base)
 103     {
 104 # define RUN_2N(BITS) \
 105       do                                                                      \
 106         {                                                                     \
 107           /* `unsigned long long int' always has 64 bits.  */                 \
 108           mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB);               \
 109                                                                               \
 110           if (BITS_PER_MP_LIMB == 32)                                         \
 111             {                                                                 \
 112               if (work_hi != 0)                                               \
 113                 {                                                             \
 114                   mp_limb_t work_lo;                                          \
 115                   int cnt;                                                    \
 116                                                                               \
 117                   work_lo = value & 0xfffffffful;                             \
 118                   for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)         \
 119                     {                                                         \
 120                       *--bp = digits[work_lo & ((1ul << BITS) - 1)];          \
 121                       work_lo >>= BITS;                                       \
 122                     }                                                         \
 123                   if (BITS_PER_MP_LIMB % BITS != 0)                           \
 124                     {                                                         \
 125                       work_lo                                                 \
 126                         |= ((work_hi                                          \
 127                              & ((1 << (BITS - BITS_PER_MP_LIMB%BITS))         \
 128                                 - 1))                                         \
 129                             << BITS_PER_MP_LIMB % BITS);                      \
 130                       work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;             \
 131                       if (work_hi == 0)                                       \
 132                         work_hi = work_lo;                                    \
 133                       else                                                    \
 134                         *--bp = digits[work_lo];                              \
 135                     }                                                         \
 136                 }                                                             \
 137               else                                                            \
 138                 work_hi = value & 0xfffffffful;                               \
 139             }                                                                 \
 140           do                                                                  \
 141             {                                                                 \
 142               *--bp = digits[work_hi & ((1 << BITS) - 1)];                    \
 143               work_hi >>= BITS;                                               \
 144             }                                                                 \
 145           while (work_hi != 0);                                               \
 146         }                                                                     \
 147       while (0)
 148     case 8:
 149       RUN_2N (3);
 150       break;
 151
 152     case 16:
 153       RUN_2N (4);
 154       break;
 155
 156     default:
 157       {
 158 # if BITS_PER_MP_LIMB == 64
 159         mp_limb_t base_multiplier = brec->base_multiplier;
 160         if (brec->flag)
 161           while (value != 0)
 162             {
 163               mp_limb_t quo, rem, x, dummy;
 164
 165               umul_ppmm (x, dummy, value, base_multiplier);
 166               quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
 167               rem = value - quo * base;
 168               *--bp = digits[rem];
 169               value = quo;
 170             }
 171         else
 172           while (value != 0)
 173             {
 174               mp_limb_t quo, rem, x, dummy;
 175
 176               umul_ppmm (x, dummy, value, base_multiplier);
 177               quo = x >> brec->post_shift;
 178               rem = value - quo * base;
 179               *--bp = digits[rem];
 180               value = quo;
 181             }
 182 # endif
 183 # if BITS_PER_MP_LIMB == 32
 184         mp_limb_t t[3];
 185         int n;
 186
 187         /* First convert x0 to 1-3 words in base s->big.base.
 188            Optimize for frequent cases of 32 bit numbers.  */
 189         if ((mp_limb_t) (value >> 32) >= 1)
 190           {
 191 # if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
 192             int big_normalization_steps = brec->big.normalization_steps;
 193             mp_limb_t big_base_norm
 194               = brec->big.base << big_normalization_steps;
 195 # endif
 196             if ((mp_limb_t) (value >> 32) >= brec->big.base)
 197               {
 198                 mp_limb_t x1hi, x1lo, r;
 199                 /* If you want to optimize this, take advantage of
 200                    that the quotient in the first udiv_qrnnd will
 201                    always be very small.  It might be faster just to
 202                    subtract in a tight loop.  */
 203
 204 # if UDIV_TIME > 2 * UMUL_TIME
 205                 mp_limb_t x, xh, xl;
 206
 207                 if (big_normalization_steps == 0)
 208                   xh = 0;
 209                 else
 210                   xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
 211                 xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
 212                 udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
 213                                    brec->big.base_ninv);
 214
 215                 xl = ((mp_limb_t) value) << big_normalization_steps;
 216                 udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
 217                                    brec->big.base_ninv);
 218                 t[2] = x >> big_normalization_steps;
 219
 220                 if (big_normalization_steps == 0)
 221                   xh = x1hi;
 222                 else
 223                   xh = ((x1hi << big_normalization_steps)
 224                         | (x1lo >> (32 - big_normalization_steps)));
 225                 xl = x1lo << big_normalization_steps;
 226                 udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
 227                                    brec->big.base_ninv);
 228                 t[1] = x >> big_normalization_steps;
 229 # elif UDIV_NEEDS_NORMALIZATION
 230                 mp_limb_t x, xh, xl;
 231
 232                 if (big_normalization_steps == 0)
 233                   xh = 0;
 234                 else
 235                   xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
 236                 xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
 237                 udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
 238
 239                 xl = ((mp_limb_t) value) << big_normalization_steps;
 240                 udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
 241                 t[2] = x >> big_normalization_steps;
 242
 243                 if (big_normalization_steps == 0)
 244                   xh = x1hi;
 245                 else
 246                   xh = ((x1hi << big_normalization_steps)
 247                         | (x1lo >> 32 - big_normalization_steps));
 248                 xl = x1lo << big_normalization_steps;
 249                 udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
 250                 t[1] = x >> big_normalization_steps;
 251 # else
 252                 udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
 253                             brec->big.base);
 254                 udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
 255                 udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
 256 # endif
 257                 n = 3;
 258               }
 259             else
 260               {
 261 # if UDIV_TIME > 2 * UMUL_TIME
 262                 mp_limb_t x;
 263
 264                 value <<= brec->big.normalization_steps;
 265                 udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
 266                                    (mp_limb_t) value, big_base_norm,
 267                                    brec->big.base_ninv);
 268                 t[1] = x >> brec->big.normalization_steps;
 269 # elif UDIV_NEEDS_NORMALIZATION
 270                 mp_limb_t x;
 271
 272                 value <<= big_normalization_steps;
 273                 udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
 274                             (mp_limb_t) value, big_base_norm);
 275                 t[1] = x >> big_normalization_steps;
 276 # else
 277                 udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
 278                             (mp_limb_t) value, brec->big.base);
 279 # endif
 280                 n = 2;
 281               }
 282           }
 283         else
 284           {
 285             t[0] = value;
 286             n = 1;
 287           }
 288
 289         /* Convert the 1-3 words in t[], word by word, to ASCII.  */
 290         do
 291           {
 292             mp_limb_t ti = t[--n];
 293             int ndig_for_this_limb = 0;
 294
 295 # if UDIV_TIME > 2 * UMUL_TIME
 296             mp_limb_t base_multiplier = brec->base_multiplier;
 297             if (brec->flag)
 298               while (ti != 0)
 299                 {
 300                   mp_limb_t quo, rem, x, dummy;
 301
 302                   umul_ppmm (x, dummy, ti, base_multiplier);
 303                   quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
 304                   rem = ti - quo * base;
 305                   *--bp = digits[rem];
 306                   ti = quo;
 307                   ++ndig_for_this_limb;
 308                 }
 309             else
 310               while (ti != 0)
 311                 {
 312                   mp_limb_t quo, rem, x, dummy;
 313
 314                   umul_ppmm (x, dummy, ti, base_multiplier);
 315                   quo = x >> brec->post_shift;
 316                   rem = ti - quo * base;
 317                   *--bp = digits[rem];
 318                   ti = quo;
 319                   ++ndig_for_this_limb;
 320                 }
 321 # else
 322             while (ti != 0)
 323               {
 324                 mp_limb_t quo, rem;
 325
 326                 quo = ti / base;
 327                 rem = ti % base;
 328                 *--bp = digits[rem];
 329                 ti = quo;
 330                 ++ndig_for_this_limb;
 331               }
 332 # endif
 333             /* If this wasn't the most significant word, pad with zeros.  */
 334             if (n != 0)
 335               while (ndig_for_this_limb < brec->big.ndigits)
 336                 {
 337                   *--bp = '0';
 338                   ++ndig_for_this_limb;
 339                 }
 340           }
 341         while (n != 0);
 342 # endif
 343       }
 344       break;
 345     }
 346
 347   return bp;
 348 }
 349 #endif