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 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 "_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 /* To reduce the memory needed we include some fields of the tables
  70    only conditionally.  */
  71 #if UDIV_TIME > 2 * UMUL_TIME
  72 # define SEL1(X) X,
  73 # define SEL2(X) ,X
  74 #else
  75 # define SEL1(X)
  76 # define SEL2(X)
  77 #endif
  78
  79
  80 /* Local variables.  */
  81 static const struct base_table_t base_table[] =
  82 {
  83 #if BITS_PER_MP_LIMB == 64
  84   /*  2 */ {SEL1(0ul) 1, 1},
  85   /*  3 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 1},
  86   /*  4 */ {SEL1(0ul) 1, 2},
  87   /*  5 */ {SEL1(0xcccccccccccccccdul) 0, 2},
  88   /*  6 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 2},
  89   /*  7 */ {SEL1(0x2492492492492493ul) 1, 3},
  90   /*  8 */ {SEL1(0ul) 1, 3},
  91   /*  9 */ {SEL1(0xe38e38e38e38e38ful) 0, 3},
  92   /* 10 */ {SEL1(0xcccccccccccccccdul) 0, 3},
  93   /* 11 */ {SEL1(0x2e8ba2e8ba2e8ba3ul) 0, 1},
  94   /* 12 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 3},
  95   /* 13 */ {SEL1(0x4ec4ec4ec4ec4ec5ul) 0, 2},
  96   /* 14 */ {SEL1(0x2492492492492493ul) 1, 4},
  97   /* 15 */ {SEL1(0x8888888888888889ul) 0, 3},
  98   /* 16 */ {SEL1(0ul) 1, 4},
  99   /* 17 */ {SEL1(0xf0f0f0f0f0f0f0f1ul) 0, 4},
 100   /* 18 */ {SEL1(0xe38e38e38e38e38ful) 0, 4},
 101   /* 19 */ {SEL1(0xd79435e50d79435ful) 0, 4},
 102   /* 20 */ {SEL1(0xcccccccccccccccdul) 0, 4},
 103   /* 21 */ {SEL1(0x8618618618618619ul) 1, 5},
 104   /* 22 */ {SEL1(0x2e8ba2e8ba2e8ba3ul) 0, 2},
 105   /* 23 */ {SEL1(0x642c8590b21642c9ul) 1, 5},
 106   /* 24 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 4},
 107   /* 25 */ {SEL1(0x47ae147ae147ae15ul) 1, 5},
 108   /* 26 */ {SEL1(0x4ec4ec4ec4ec4ec5ul) 0, 3},
 109   /* 27 */ {SEL1(0x97b425ed097b425ful) 0, 4},
 110   /* 28 */ {SEL1(0x2492492492492493ul) 1, 5},
 111   /* 29 */ {SEL1(0x1a7b9611a7b9611bul) 1, 5},
 112   /* 30 */ {SEL1(0x8888888888888889ul) 0, 4},
 113   /* 31 */ {SEL1(0x0842108421084211ul) 1, 5},
 114   /* 32 */ {SEL1(0ul) 1, 5},
 115   /* 33 */ {SEL1(0x0f83e0f83e0f83e1ul) 0, 1},
 116   /* 34 */ {SEL1(0xf0f0f0f0f0f0f0f1ul) 0, 5},
 117   /* 35 */ {SEL1(0xea0ea0ea0ea0ea0ful) 0, 5},
 118   /* 36 */ {SEL1(0xe38e38e38e38e38ful) 0, 5}
 119 #endif
 120 #if BITS_PER_MP_LIMB == 32
 121   /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
 122   /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 123   /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
 124   /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
 125   /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
 126   /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
 127   /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
 128   /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 129   /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
 130   /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
 131   /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
 132   /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
 133   /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
 134   /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
 135   /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
 136   /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
 137   /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
 138   /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
 139   /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
 140   /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
 141   /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
 142   /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
 143   /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
 144   /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
 145   /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
 146   /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
 147   /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
 148   /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
 149   /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
 150   /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
 151   /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
 152   /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
 153   /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
 154   /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
 155   /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
 156 #endif
 157 };
 158
 159 /* Lower-case digits.  */
 160 extern const char _itoa_lower_digits[];
 161 /* Upper-case digits.  */
 162 extern const char _itoa_upper_digits[];
 163
 164
 165 char *
 166 _itoa (value, buflim, base, upper_case)
 167      unsigned long long int value;
 168      char *buflim;
 169      unsigned int base;
 170      int upper_case;
 171 {
 172   const char *digits = upper_case ? _itoa_upper_digits : _itoa_lower_digits;
 173   char *bp = buflim;
 174   const struct base_table_t *brec = &base_table[base - 2];
 175
 176   switch (base)
 177     {
 178 #define RUN_2N(BITS)                                                      \
 179       do                                                                  \
 180         {                                                                 \
 181           /* `unsigned long long int' always has 64 bits.  */             \
 182           mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB);           \
 183                                                                           \
 184           if (BITS_PER_MP_LIMB == 32)                                     \
 185             {                                                             \
 186               if (work_hi != 0)                                           \
 187                 {                                                         \
 188                   mp_limb_t work_lo;                                      \
 189                   int cnt;                                                \
 190                                                                           \
 191                   work_lo = value & 0xfffffffful;                         \
 192                   for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)     \
 193                     {                                                     \
 194                       *--bp = digits[work_lo & ((1ul << BITS) - 1)];      \
 195                       work_lo >>= BITS;                                   \
 196                     }                                                     \
 197                   if (BITS_PER_MP_LIMB % BITS != 0)                       \
 198                     {                                                     \
 199                       work_lo                                             \
 200                         |= ((work_hi                                      \
 201                              & ((1 << (BITS - BITS_PER_MP_LIMB%BITS))     \
 202                                 - 1))                                     \
 203                             << BITS_PER_MP_LIMB % BITS);                  \
 204                       *--bp = digits[work_lo];                            \
 205                       work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;         \
 206                     }                                                     \
 207                 }                                                         \
 208               else                                                        \
 209                 work_hi = value & 0xfffffffful;                           \
 210             }                                                             \
 211           do                                                              \
 212             {                                                             \
 213               *--bp = digits[work_hi & ((1 << BITS) - 1)];                \
 214               work_hi >>= BITS;                                           \
 215             }                                                             \
 216           while (work_hi != 0);                                           \
 217         }                                                                 \
 218       while (0)
 219     case 8:
 220       RUN_2N (3);
 221       break;
 222
 223     case 16:
 224       RUN_2N (4);
 225       break;
 226
 227     default:
 228       {
 229 #if BITS_PER_MP_LIMB == 64
 230         mp_limb_t base_multiplier = brec->base_multiplier;
 231         if (brec->flag)
 232           while (value != 0)
 233             {
 234               mp_limb_t quo, rem, x, dummy;
 235
 236               umul_ppmm (x, dummy, value, base_multiplier);
 237               quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
 238               rem = value - quo * base;
 239               *--bp = digits[rem];
 240               value = quo;
 241             }
 242         else
 243           while (value != 0)
 244             {
 245               mp_limb_t quo, rem, x, dummy;
 246
 247               umul_ppmm (x, dummy, value, base_multiplier);
 248               quo = x >> brec->post_shift;
 249               rem = value - quo * base;
 250               *--bp = digits[rem];
 251               value = quo;
 252             }
 253 #endif
 254 #if BITS_PER_MP_LIMB == 32
 255         mp_limb_t t[3];
 256         int n;
 257
 258         /* First convert x0 to 1-3 words in base s->big.base.
 259            Optimize for frequent cases of 32 bit numbers.  */
 260         if ((mp_limb_t) (value >> 32) >= 1)
 261           {
 262 #if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
 263             int big_normalization_steps = brec->big.normalization_steps;
 264             mp_limb_t big_base_norm
 265               = brec->big.base << big_normalization_steps;
 266 #endif
 267             if ((mp_limb_t) (value >> 32) >= brec->big.base)
 268               {
 269                 mp_limb_t x1hi, x1lo, r;
 270                 /* If you want to optimize this, take advantage of
 271                    that the quotient in the first udiv_qrnnd will
 272                    always be very small.  It might be faster just to
 273                    subtract in a tight loop.  */
 274
 275 #if UDIV_TIME > 2 * UMUL_TIME
 276                 mp_limb_t x, xh, xl;
 277
 278                 if (big_normalization_steps == 0)
 279                   xh = 0;
 280                 else
 281                   xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
 282                 xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
 283                 udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
 284                                    brec->big.base_ninv);
 285
 286                 xl = ((mp_limb_t) value) << big_normalization_steps;
 287                 udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
 288                                    big_normalization_steps);
 289                 t[2] = x >> big_normalization_steps;
 290
 291                 if (big_normalization_steps == 0)
 292                   xh = x1hi;
 293                 else
 294                   xh = ((x1hi << big_normalization_steps)
 295                         | (x1lo >> (32 - big_normalization_steps)));
 296                 xl = x1lo << big_normalization_steps;
 297                 udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
 298                                    big_normalization_steps);
 299                 t[1] = x >> big_normalization_steps;
 300 #elif UDIV_NEEDS_NORMALIZATION
 301                 mp_limb_t x, xh, xl;
 302
 303                 if (big_normalization_steps == 0)
 304                   xh = 0;
 305                 else
 306                   xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
 307                 xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
 308                 udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
 309
 310                 xl = ((mp_limb_t) value) << big_normalization_steps;
 311                 udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
 312                 t[2] = x >> big_normalization_steps;
 313
 314                 if (big_normalization_steps == 0)
 315                   xh = x1hi;
 316                 else
 317                   xh = ((x1hi << big_normalization_steps)
 318                         | (x1lo >> 32 - big_normalization_steps));
 319                 xl = x1lo << big_normalization_steps;
 320                 udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
 321                 t[1] = x >> big_normalization_steps;
 322 #else
 323                 udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
 324                             brec->big.base);
 325                 udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
 326                 udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
 327 #endif
 328                 n = 3;
 329               }
 330             else
 331               {
 332 #if (UDIV_TIME > 2 * UMUL_TIME)
 333                 mp_limb_t x;
 334
 335                 value <<= brec->big.normalization_steps;
 336                 udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
 337                                    (mp_limb_t) value, big_base_norm,
 338                                    brec->big.base_ninv);
 339                 t[1] = x >> brec->big.normalization_steps;
 340 #elif UDIV_NEEDS_NORMALIZATION
 341                 mp_limb_t x;
 342
 343                 value <<= big_normalization_steps;
 344                 udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
 345                             (mp_limb_t) value, big_base_norm);
 346                 t[1] = x >> big_normalization_steps;
 347 #else
 348                 udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
 349                             (mp_limb_t) value, brec->big.base);
 350 #endif
 351                 n = 2;
 352               }
 353           }
 354         else
 355           {
 356             t[0] = value;
 357             n = 1;
 358           }
 359
 360         /* Convert the 1-3 words in t[], word by word, to ASCII.  */
 361         do
 362           {
 363             mp_limb_t ti = t[--n];
 364             int ndig_for_this_limb = 0;
 365
 366 #if UDIV_TIME > 2 * UMUL_TIME
 367             mp_limb_t base_multiplier = brec->base_multiplier;
 368             if (brec->flag)
 369               while (ti != 0)
 370                 {
 371                   mp_limb_t quo, rem, x, dummy;
 372
 373                   umul_ppmm (x, dummy, ti, base_multiplier);
 374                   quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
 375                   rem = ti - quo * base;
 376                   *--bp = digits[rem];
 377                   ti = quo;
 378                   ++ndig_for_this_limb;
 379                 }
 380             else
 381               while (ti != 0)
 382                 {
 383                   mp_limb_t quo, rem, x, dummy;
 384
 385                   umul_ppmm (x, dummy, ti, base_multiplier);
 386                   quo = x >> brec->post_shift;
 387                   rem = ti - quo * base;
 388                   *--bp = digits[rem];
 389                   ti = quo;
 390                   ++ndig_for_this_limb;
 391                 }
 392 #else
 393             while (ti != 0)
 394               {
 395                 mp_limb_t quo, rem;
 396
 397                 quo = ti / base;
 398                 rem = ti % base;
 399                 *--bp = digits[rem];
 400                 ti = quo;
 401                 ++ndig_for_this_limb;
 402               }
 403 #endif
 404             /* If this wasn't the most significant word, pad with zeros.  */
 405             if (n != 0)
 406               while (ndig_for_this_limb < brec->big.ndigits)
 407                 {
 408                   *--bp = '0';
 409                   ++ndig_for_this_limb;
 410                 }
 411           }
 412         while (n != 0);
 413 #endif
 414       }
 415       break;
 416     }
 417
 418   return bp;
 419 }