Update NOTES.opensolaris with scheduling details
[kopensolaris-gnu/glibc.git] / 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