1 /* Internal function for converting integers to ASCII.
2 Copyright (C) 1994-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <gmp-mparam.h>
20 #include <gmp.h>
21 #include <limits.h>
22 #include <stdlib/gmp-impl.h>
23 #include <stdlib/longlong.h>
24
25 #include <_itowa.h>
26
27
28 /* Canonize environment. For some architectures not all values might
29 be defined in the GMP header files. */
30 #ifndef UMUL_TIME
31 # define UMUL_TIME 1
32 #endif
33 #ifndef UDIV_TIME
34 # define UDIV_TIME 3
35 #endif
36
37 /* Control memory layout. */
38 #ifdef PACK
39 # undef PACK
40 # define PACK __attribute__ ((packed))
41 #else
42 # define PACK
43 #endif
44
45
46 /* Declare local types. */
47 struct base_table_t
48 {
49 #if (UDIV_TIME > 2 * UMUL_TIME)
50 mp_limb_t base_multiplier;
51 #endif
52 char flag;
53 char post_shift;
54 #if BITS_PER_MP_LIMB == 32
55 struct
56 {
57 char normalization_steps;
58 char ndigits;
59 mp_limb_t base PACK;
60 #if UDIV_TIME > 2 * UMUL_TIME
61 mp_limb_t base_ninv PACK;
62 #endif
63 } big;
64 #endif
65 };
66
67 /* To reduce the memory needed we include some fields of the tables
68 only conditionally. */
69 #if UDIV_TIME > 2 * UMUL_TIME
70 # define SEL1(X) X,
71 # define SEL2(X) ,X
72 #else
73 # define SEL1(X)
74 # define SEL2(X)
75 #endif
76
77 /* Factor table for the different bases. */
78 extern const struct base_table_t _itoa_base_table[] attribute_hidden;
79
80 /* Lower-case digits. */
81 extern const wchar_t _itowa_lower_digits[] attribute_hidden;
82 /* Upper-case digits. */
83 extern const wchar_t _itowa_upper_digits[] attribute_hidden;
84
85
86 #if _ITOA_NEEDED
87 wchar_t *
88 _itowa (unsigned long long int value, wchar_t *buflim, unsigned int base,
89 int upper_case)
90 {
91 const wchar_t *digits = (upper_case
92 ? _itowa_upper_digits : _itowa_lower_digits);
93 wchar_t *bp = buflim;
94 const struct base_table_t *brec = &_itoa_base_table[base - 2];
95
96 switch (base)
97 {
98 # define RUN_2N(BITS) \
99 do \
100 { \
101 /* `unsigned long long int' always has 64 bits. */ \
102 mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB); \
103 \
104 if (BITS_PER_MP_LIMB == 32) \
105 { \
106 if (work_hi != 0) \
107 { \
108 mp_limb_t work_lo; \
109 int cnt; \
110 \
111 work_lo = value & 0xfffffffful; \
112 for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt) \
113 { \
114 *--bp = digits[work_lo & ((1ul << BITS) - 1)]; \
115 work_lo >>= BITS; \
116 } \
117 if (BITS_PER_MP_LIMB % BITS != 0) \
118 { \
119 work_lo \
120 |= ((work_hi \
121 & ((1 << (BITS - BITS_PER_MP_LIMB%BITS)) \
122 - 1)) \
123 << BITS_PER_MP_LIMB % BITS); \
124 work_hi >>= BITS - BITS_PER_MP_LIMB % BITS; \
125 if (work_hi == 0) \
126 work_hi = work_lo; \
127 else \
128 *--bp = digits[work_lo]; \
129 } \
130 } \
131 else \
132 work_hi = value & 0xfffffffful; \
133 } \
134 do \
135 { \
136 *--bp = digits[work_hi & ((1 << BITS) - 1)]; \
137 work_hi >>= BITS; \
138 } \
139 while (work_hi != 0); \
140 } \
141 while (0)
142 case 8:
143 RUN_2N (3);
144 break;
145
146 case 16:
147 RUN_2N (4);
148 break;
149
150 default:
151 {
152 # if BITS_PER_MP_LIMB == 64
153 mp_limb_t base_multiplier = brec->base_multiplier;
154 if (brec->flag)
155 while (value != 0)
156 {
157 mp_limb_t quo, rem, x;
158 mp_limb_t dummy __attribute__ ((unused));
159
160 umul_ppmm (x, dummy, value, base_multiplier);
161 quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
162 rem = value - quo * base;
163 *--bp = digits[rem];
164 value = quo;
165 }
166 else
167 while (value != 0)
168 {
169 mp_limb_t quo, rem, x;
170 mp_limb_t dummy __attribute__ ((unused));
171
172 umul_ppmm (x, dummy, value, base_multiplier);
173 quo = x >> brec->post_shift;
174 rem = value - quo * base;
175 *--bp = digits[rem];
176 value = quo;
177 }
178 # endif
179 # if BITS_PER_MP_LIMB == 32
180 mp_limb_t t[3];
181 int n;
182
183 /* First convert x0 to 1-3 words in base s->big.base.
184 Optimize for frequent cases of 32 bit numbers. */
185 if ((mp_limb_t) (value >> 32) >= 1)
186 {
187 # if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
188 int big_normalization_steps = brec->big.normalization_steps;
189 mp_limb_t big_base_norm
190 = brec->big.base << big_normalization_steps;
191 # endif
192 if ((mp_limb_t) (value >> 32) >= brec->big.base)
193 {
194 mp_limb_t x1hi, x1lo, r;
195 /* If you want to optimize this, take advantage of
196 that the quotient in the first udiv_qrnnd will
197 always be very small. It might be faster just to
198 subtract in a tight loop. */
199
200 # if UDIV_TIME > 2 * UMUL_TIME
201 mp_limb_t x, xh, xl;
202
203 if (big_normalization_steps == 0)
204 xh = 0;
205 else
206 xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
207 xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
208 udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
209 brec->big.base_ninv);
210
211 xl = ((mp_limb_t) value) << big_normalization_steps;
212 udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
213 brec->big.base_ninv);
214 t[2] = x >> big_normalization_steps;
215
216 if (big_normalization_steps == 0)
217 xh = x1hi;
218 else
219 xh = ((x1hi << big_normalization_steps)
220 | (x1lo >> (32 - big_normalization_steps)));
221 xl = x1lo << big_normalization_steps;
222 udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
223 brec->big.base_ninv);
224 t[1] = x >> big_normalization_steps;
225 # elif UDIV_NEEDS_NORMALIZATION
226 mp_limb_t x, xh, xl;
227
228 if (big_normalization_steps == 0)
229 xh = 0;
230 else
231 xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
232 xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
233 udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
234
235 xl = ((mp_limb_t) value) << big_normalization_steps;
236 udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
237 t[2] = x >> big_normalization_steps;
238
239 if (big_normalization_steps == 0)
240 xh = x1hi;
241 else
242 xh = ((x1hi << big_normalization_steps)
243 | (x1lo >> 32 - big_normalization_steps));
244 xl = x1lo << big_normalization_steps;
245 udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
246 t[1] = x >> big_normalization_steps;
247 # else
248 udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
249 brec->big.base);
250 udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
251 udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
252 # endif
253 n = 3;
254 }
255 else
256 {
257 # if UDIV_TIME > 2 * UMUL_TIME
258 mp_limb_t x;
259
260 value <<= brec->big.normalization_steps;
261 udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
262 (mp_limb_t) value, big_base_norm,
263 brec->big.base_ninv);
264 t[1] = x >> brec->big.normalization_steps;
265 # elif UDIV_NEEDS_NORMALIZATION
266 mp_limb_t x;
267
268 value <<= big_normalization_steps;
269 udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
270 (mp_limb_t) value, big_base_norm);
271 t[1] = x >> big_normalization_steps;
272 # else
273 udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
274 (mp_limb_t) value, brec->big.base);
275 # endif
276 n = 2;
277 }
278 }
279 else
280 {
281 t[0] = value;
282 n = 1;
283 }
284
285 /* Convert the 1-3 words in t[], word by word, to ASCII. */
286 do
287 {
288 mp_limb_t ti = t[--n];
289 int ndig_for_this_limb = 0;
290
291 # if UDIV_TIME > 2 * UMUL_TIME
292 mp_limb_t base_multiplier = brec->base_multiplier;
293 if (brec->flag)
294 while (ti != 0)
295 {
296 mp_limb_t quo, rem, x;
297 mp_limb_t dummy __attribute__ ((unused));
298
299 umul_ppmm (x, dummy, ti, base_multiplier);
300 quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
301 rem = ti - quo * base;
302 *--bp = digits[rem];
303 ti = quo;
304 ++ndig_for_this_limb;
305 }
306 else
307 while (ti != 0)
308 {
309 mp_limb_t quo, rem, x;
310 mp_limb_t dummy __attribute__ ((unused));
311
312 umul_ppmm (x, dummy, ti, base_multiplier);
313 quo = x >> brec->post_shift;
314 rem = ti - quo * base;
315 *--bp = digits[rem];
316 ti = quo;
317 ++ndig_for_this_limb;
318 }
319 # else
320 while (ti != 0)
321 {
322 mp_limb_t quo, rem;
323
324 quo = ti / base;
325 rem = ti % base;
326 *--bp = digits[rem];
327 ti = quo;
328 ++ndig_for_this_limb;
329 }
330 # endif
331 /* If this wasn't the most significant word, pad with zeros. */
332 if (n != 0)
333 while (ndig_for_this_limb < brec->big.ndigits)
334 {
335 *--bp = '0';
336 ++ndig_for_this_limb;
337 }
338 }
339 while (n != 0);
340 # endif
341 }
342 break;
343 }
344
345 return bp;
346 }
347 #endif