stdio-common/_itoa.c

   1 /* Internal function for converting integers to ASCII.
   2 Copyright (C) 1994, 1995, 1996 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.ai.mit.edu>.
   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
  19 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  20 Cambridge, MA 02139, 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 "_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 1
  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 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 base PACK;
  62 #if UDIV_TIME > 2 * UMUL_TIME
  63       mp_limb base_ninv PACK;
  64 #endif
  65     } big;
  66 #endif
  67 };
  68
  69 /* To reduce the memory needed we include some fields of the tables
  70    only confitionally.  */
  71 #if BITS_PER_MP_LIMB == 32
  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 #endif
  80
  81
  82 /* Local variables.  */
  83 static const struct base_table_t base_table[] =
  84 {
  85 #if BITS_PER_MP_LIMB == 64
  86   /*  2 */ {0ul, 1, 1},
  87   /*  3 */ {0xaaaaaaaaaaaaaaabul, 0, 1},
  88   /*  4 */ {0ul, 1, 2},
  89   /*  5 */ {0xcccccccccccccccdul, 0, 2},
  90   /*  6 */ {0xaaaaaaaaaaaaaaabul, 0, 2},
  91   /*  7 */ {0x2492492492492493ul, 1, 3},
  92   /*  8 */ {0ul, 1, 3},
  93   /*  9 */ {0xe38e38e38e38e38ful, 0, 3},
  94   /* 10 */ {0xcccccccccccccccdul, 0, 3},
  95   /* 11 */ {0x2e8ba2e8ba2e8ba3ul, 0, 1},
  96   /* 12 */ {0xaaaaaaaaaaaaaaabul, 0, 3},
  97   /* 13 */ {0x4ec4ec4ec4ec4ec5ul, 0, 2},
  98   /* 14 */ {0x2492492492492493ul, 1, 4},
  99   /* 15 */ {0x8888888888888889ul, 0, 3},
 100   /* 16 */ {0ul, 1, 4},
 101   /* 17 */ {0xf0f0f0f0f0f0f0f1ul, 0, 4},
 102   /* 18 */ {0xe38e38e38e38e38ful, 0, 4},
 103   /* 19 */ {0xd79435e50d79435ful, 0, 4},
 104   /* 20 */ {0xcccccccccccccccdul, 0, 4},
 105   /* 21 */ {0x8618618618618619ul, 1, 5},
 106   /* 22 */ {0x2e8ba2e8ba2e8ba3ul, 0, 2},
 107   /* 23 */ {0x642c8590b21642c9ul, 1, 5},
 108   /* 24 */ {0xaaaaaaaaaaaaaaabul, 0, 4},
 109   /* 25 */ {0x47ae147ae147ae15ul, 1, 5},
 110   /* 26 */ {0x4ec4ec4ec4ec4ec5ul, 0, 3},
 111   /* 27 */ {0x97b425ed097b425ful, 0, 4},
 112   /* 28 */ {0x2492492492492493ul, 1, 5},
 113   /* 29 */ {0x1a7b9611a7b9611bul, 1, 5},
 114   /* 30 */ {0x8888888888888889ul, 0, 4},
 115   /* 31 */ {0x0842108421084211ul, 1, 5},
 116   /* 32 */ {0ul, 1, 5},
 117   /* 33 */ {0x0f83e0f83e0f83e1ul, 0, 1},
 118   /* 34 */ {0xf0f0f0f0f0f0f0f1ul, 0, 5},
 119   /* 35 */ {0xea0ea0ea0ea0ea0ful, 0, 5},
 120   /* 36 */ {0xe38e38e38e38e38ful, 0, 5}
 121 #endif
 122 #if BITS_PER_MP_LIMB == 32
 123   /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
 124   /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 125   /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
 126   /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
 127   /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
 128   /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
 129   /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
 130   /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 131   /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
 132   /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
 133   /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
 134   /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
 135   /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
 136   /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
 137   /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
 138   /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
 139   /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
 140   /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
 141   /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
 142   /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
 143   /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
 144   /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
 145   /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
 146   /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
 147   /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
 148   /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
 149   /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
 150   /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
 151   /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
 152   /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
 153   /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
 154   /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
 155   /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
 156   /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
 157   /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
 158 #endif
 159 };
 160
 161 /* Lower-case digits.  */
 162 const char _itoa_lower_digits[]
 163         = "0123456789abcdefghijklmnopqrstuvwxyz";
 164 /* Upper-case digits.  */
 165 const char _itoa_upper_digits[]
 166         = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 167
 168
 169 char *
 170 _itoa (value, buflim, base, upper_case)
 171      unsigned long long int value;
 172      char *buflim;
 173      unsigned int base;
 174      int upper_case;
 175 {
 176   const char *digits = upper_case ? _itoa_upper_digits : _itoa_lower_digits;
 177   char *bp = buflim;
 178   const struct base_table_t *brec = &base_table[base - 2];
 179
 180   switch (base)
 181     {
 182 #define RUN_2N(BITS)                                                      \
 183       do                                                                  \
 184         {                                                                 \
 185           /* `unsigned long long int' always has 64 bits.  */             \
 186           mp_limb work_hi = value >> (64 - BITS_PER_MP_LIMB);             \
 187                                                                           \
 188           if (BITS_PER_MP_LIMB == 32)                                     \
 189             if (work_hi != 0)                                             \
 190               {                                                           \
 191                 mp_limb work_lo;                                          \
 192                 int cnt;                                                  \
 193                                                                           \
 194                 work_lo = value & 0xfffffffful;                           \
 195                 for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)       \
 196                   {                                                       \
 197                     *--bp = digits[work_lo & ((1ul << BITS) - 1)];        \
 198                     work_lo >>= BITS;                                     \
 199                   }                                                       \
 200                 if (BITS_PER_MP_LIMB % BITS != 0)                         \
 201                   {                                                       \
 202                     work_lo |= ((work_hi                                  \
 203                                  & ((1 << BITS - BITS_PER_MP_LIMB % BITS) \
 204                                     - 1))                                 \
 205                                 << BITS_PER_MP_LIMB % BITS);              \
 206                     *--bp = digits[work_lo];                              \
 207                     work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;           \
 208                   }                                                       \
 209               }                                                           \
 210             else                                                          \
 211               work_hi = value & 0xfffffffful;                             \
 212           do                                                              \
 213             {                                                             \
 214               *--bp = digits[work_hi & ((1 << BITS) - 1)];                \
 215               work_hi >>= BITS;                                           \
 216             }                                                             \
 217           while (work_hi != 0);                                           \
 218         }                                                                 \
 219       while (0)
 220     case 8:
 221       RUN_2N (3);
 222       break;
 223
 224     case 16:
 225       RUN_2N (4);
 226       break;
 227
 228     default:
 229       {
 230 #if BITS_PER_MP_LIMB == 64
 231         mp_limb base_multiplier = brec->base_multiplier;
 232         if (brec->flag)
 233           while (value != 0)
 234             {
 235               mp_limb quo, rem, x, dummy;
 236
 237               umul_ppmm (x, dummy, value, base_multiplier);
 238               quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
 239               rem = value - quo * base;
 240               *--bp = digits[rem];
 241               value = quo;
 242             }
 243         else
 244           while (value != 0)
 245             {
 246               mp_limb quo, rem, x, dummy;
 247
 248               umul_ppmm (x, dummy, value, base_multiplier);
 249               quo = x >> brec->post_shift;
 250               rem = value - quo * base;
 251               *--bp = digits[rem];
 252               value = quo;
 253             }
 254 #endif
 255 #if BITS_PER_MP_LIMB == 32
 256         mp_limb t[3];
 257         int n;
 258
 259         /* First convert x0 to 1-3 words in base s->big.base.
 260            Optimize for frequent cases of 32 bit numbers.  */
 261         if ((mp_limb) (value >> 32) >= 1)
 262           {
 263             int big_normalization_steps = brec->big.normalization_steps;
 264             mp_limb big_base_norm = brec->big.base << big_normalization_steps;
 265
 266             if ((mp_limb) (value >> 32) >= brec->big.base)
 267               {
 268                 mp_limb x1hi, x1lo, r;
 269                 /* If you want to optimize this, take advantage of
 270                    that the quotient in the first udiv_qrnnd will
 271                    always be very small.  It might be faster just to
 272                    subtract in a tight loop.  */
 273
 274 #if UDIV_TIME > 2 * UMUL_TIME
 275                 mp_limb x, xh, xl;
 276
 277                 if (big_normalization_steps == 0)
 278                   xh = 0;
 279                 else
 280                   xh = (mp_limb) (value >> 64 - big_normalization_steps);
 281                 xl = (mp_limb) (value >> 32 - big_normalization_steps);
 282                 udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
 283                                    brec->big.base_ninv);
 284
 285                 xl = ((mp_limb) value) << big_normalization_steps;
 286                 udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
 287                                    big_normalization_steps);
 288                 t[2] = x >> big_normalization_steps;
 289
 290                 if (big_normalization_steps == 0)
 291                   xh = x1hi;
 292                 else
 293                   xh = ((x1hi << big_normalization_steps)
 294                         | (x1lo >> 32 - big_normalization_steps));
 295                 xl = x1lo << big_normalization_steps;
 296                 udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
 297                                    big_normalization_steps);
 298                 t[1] = x >> big_normalization_steps;
 299 #elif UDIV_NEEDS_NORMALIZATION
 300                 mp_limb x, xh, xl;
 301
 302                 if (big_normalization_steps == 0)
 303                   xh = 0;
 304                 else
 305                   xh = (mp_limb) (value >> 64 - big_normalization_steps);
 306                 xl = (mp_limb) (value >> 32 - big_normalization_steps);
 307                 udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
 308
 309                 xl = ((mp_limb) value) << big_normalization_steps;
 310                 udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
 311                 t[2] = x >> big_normalization_steps;
 312
 313                 if (big_normalization_steps == 0)
 314                   xh = x1hi;
 315                 else
 316                   xh = ((x1hi << big_normalization_steps)
 317                         | (x1lo >> 32 - big_normalization_steps));
 318                 xl = x1lo << big_normalization_steps;
 319                 udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
 320                 t[1] = x >> big_normalization_steps;
 321 #else
 322                 udiv_qrnnd (x1hi, r, 0, (mp_limb) (value >> 32),
 323                             brec->big.base);
 324                 udiv_qrnnd (x1lo, t[2], r, (mp_limb) value, brec->big.base);
 325                 udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
 326 #endif
 327                 n = 3;
 328               }
 329             else
 330               {
 331 #if (UDIV_TIME > 2 * UMUL_TIME)
 332                 mp_limb x;
 333
 334                 value <<= brec->big.normalization_steps;
 335                 udiv_qrnnd_preinv (t[0], x, (mp_limb) (value >> 32),
 336                                    (mp_limb) value, big_base_norm,
 337                                    brec->big.base_ninv);
 338                 t[1] = x >> brec->big.normalization_steps;
 339 #elif UDIV_NEEDS_NORMALIZATION
 340                 mp_limb x;
 341
 342                 value <<= big_normalization_steps;
 343                 udiv_qrnnd (t[0], x, (mp_limb) (value >> 32),
 344                             (mp_limb) value, big_base_norm);
 345                 t[1] = x >> big_normalization_steps;
 346 #else
 347                 udiv_qrnnd (t[0], t[1], (mp_limb) (value >> 32),
 348                             (mp_limb) value, brec->big.base);
 349 #endif
 350                 n = 2;
 351               }
 352           }
 353         else
 354           {
 355             t[0] = value;
 356             n = 1;
 357           }
 358
 359         /* Convert the 1-3 words in t[], word by word, to ASCII.  */
 360         do
 361           {
 362             mp_limb ti = t[--n];
 363             int ndig_for_this_limb = 0;
 364
 365 #if UDIV_TIME > 2 * UMUL_TIME
 366             mp_limb base_multiplier = brec->base_multiplier;
 367             if (brec->flag)
 368               while (ti != 0)
 369                 {
 370                   mp_limb quo, rem, x, dummy;
 371
 372                   umul_ppmm (x, dummy, ti, base_multiplier);
 373                   quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
 374                   rem = ti - quo * base;
 375                   *--bp = digits[rem];
 376                   ti = quo;
 377                   ++ndig_for_this_limb;
 378                 }
 379             else
 380               while (ti != 0)
 381                 {
 382                   mp_limb quo, rem, x, dummy;
 383
 384                   umul_ppmm (x, dummy, ti, base_multiplier);
 385                   quo = x >> brec->post_shift;
 386                   rem = ti - quo * base;
 387                   *--bp = digits[rem];
 388                   ti = quo;
 389                   ++ndig_for_this_limb;
 390                 }
 391 #else
 392             while (ti != 0)
 393               {
 394                 mp_limb quo, rem;
 395
 396                 quo = ti / base;
 397                 rem = ti % base;
 398                 *--bp = digits[rem];
 399                 ti = quo;
 400                 ++ndig_for_this_limb;
 401               }
 402 #endif
 403             /* If this wasn't the most significant word, pad with zeros.  */
 404             if (n != 0)
 405               while (ndig_for_this_limb < brec->big.ndigits)
 406                 {
 407                   *--bp = '0';
 408                   ++ndig_for_this_limb;
 409                 }
 410           }
 411         while (n != 0);
 412 #endif
 413       }
 414       break;
 415     }
 416
 417   return bp;
 418 }