1/* Generate mp_bases data.
2
3Copyright 1991, 1993, 1994, 1996, 2000, 2002, 2004 Free Software Foundation,
4Inc.
5
6This file is part of the GNU MP Library.
7
8The GNU MP Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MP Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
20
21#include <math.h>
22
23#include "dumbmp.c"
24
25
26int    chars_per_limb;
27double chars_per_bit_exactly;
28mpz_t  big_base;
29int    normalization_steps;
30mpz_t  big_base_inverted;
31
32mpz_t  t;
33
34#define POW2_P(n)  (((n) & ((n) - 1)) == 0)
35
36unsigned int
37ulog2 (unsigned int x)
38{
39  unsigned int i;
40  for (i = 0;  x != 0;  i++)
41    x >>= 1;
42  return i;
43}
44
45void
46generate (int limb_bits, int nail_bits, int base)
47{
48  int  numb_bits = limb_bits - nail_bits;
49
50  mpz_set_ui (t, 1L);
51  mpz_mul_2exp (t, t, numb_bits);
52  mpz_set_ui (big_base, 1L);
53  chars_per_limb = 0;
54  for (;;)
55    {
56      mpz_mul_ui (big_base, big_base, (long) base);
57      if (mpz_cmp (big_base, t) > 0)
58        break;
59      chars_per_limb++;
60    }
61
62  chars_per_bit_exactly = 0.69314718055994530942 / log ((double) base);
63
64  mpz_ui_pow_ui (big_base, (long) base, (long) chars_per_limb);
65
66  normalization_steps = limb_bits - mpz_sizeinbase (big_base, 2);
67
68  mpz_set_ui (t, 1L);
69  mpz_mul_2exp (t, t, 2*limb_bits - normalization_steps);
70  mpz_tdiv_q (big_base_inverted, t, big_base);
71  mpz_set_ui (t, 1L);
72  mpz_mul_2exp (t, t, limb_bits);
73  mpz_sub (big_base_inverted, big_base_inverted, t);
74}
75
76void
77header (int limb_bits, int nail_bits)
78{
79  int  numb_bits = limb_bits - nail_bits;
80
81  generate (limb_bits, nail_bits, 10);
82
83  printf ("/* This file generated by gen-bases.c - DO NOT EDIT. */\n");
84  printf ("\n");
85  printf ("#if GMP_NUMB_BITS != %d\n", numb_bits);
86  printf ("Error, error, this data is for %d bits\n", numb_bits);
87  printf ("#endif\n");
88  printf ("\n");
89  printf ("/* mp_bases[10] data, as literal values */\n");
90  printf ("#define MP_BASES_CHARS_PER_LIMB_10      %d\n", chars_per_limb);
91  printf ("#define MP_BASES_BIG_BASE_10            CNST_LIMB(0x");
92  mpz_out_str (stdout, 16, big_base);
93  printf (")\n");
94  printf ("#define MP_BASES_BIG_BASE_INVERTED_10   CNST_LIMB(0x");
95  mpz_out_str (stdout, 16, big_base_inverted);
96  printf (")\n");
97  printf ("#define MP_BASES_NORMALIZATION_STEPS_10 %d\n", normalization_steps);
98}
99
100void
101table (int limb_bits, int nail_bits)
102{
103  int  numb_bits = limb_bits - nail_bits;
104  int  base;
105
106  printf ("/* This file generated by gen-bases.c - DO NOT EDIT. */\n");
107  printf ("\n");
108  printf ("#include \"gmp.h\"\n");
109  printf ("#include \"gmp-impl.h\"\n");
110  printf ("\n");
111  printf ("#if GMP_NUMB_BITS != %d\n", numb_bits);
112  printf ("Error, error, this data is for %d bits\n", numb_bits);
113  printf ("#endif\n");
114  printf ("\n");
115  puts ("const struct bases mp_bases[257] =\n{");
116  puts ("  /*   0 */ { 0, 0.0, 0 },");
117  puts ("  /*   1 */ { 0, 1e37, 0 },");
118  for (base = 2; base <= 256; base++)
119    {
120      generate (limb_bits, nail_bits, base);
121
122      printf ("  /* %3u */ { ", base);
123      if (POW2_P (base))
124	{
125          printf ("%u, %.16f, 0x%x },\n",
126                  chars_per_limb, chars_per_bit_exactly, ulog2 (base) - 1);
127	}
128      else
129	{
130          printf ("%u, %.16f, CNST_LIMB(0x",
131                  chars_per_limb, chars_per_bit_exactly);
132	  mpz_out_str (stdout, 16, big_base);
133          printf ("), CNST_LIMB(0x");
134	  mpz_out_str (stdout, 16, big_base_inverted);
135          printf (") },\n");
136	}
137    }
138
139  puts ("};");
140}
141
142int
143main (int argc, char **argv)
144{
145  int  limb_bits, nail_bits;
146
147  mpz_init (big_base);
148  mpz_init (big_base_inverted);
149  mpz_init (t);
150
151  if (argc != 4)
152    {
153      fprintf (stderr, "Usage: gen-bases <header|table> <limbbits> <nailbits>\n");
154      exit (1);
155    }
156
157  limb_bits = atoi (argv[2]);
158  nail_bits = atoi (argv[3]);
159
160  if (limb_bits <= 0
161      || nail_bits < 0
162      || nail_bits >= limb_bits)
163    {
164      fprintf (stderr, "Invalid limb/nail bits: %d %d\n",
165               limb_bits, nail_bits);
166      exit (1);
167    }
168
169  if (strcmp (argv[1], "header") == 0)
170    header (limb_bits, nail_bits);
171  else if (strcmp (argv[1], "table") == 0)
172    table (limb_bits, nail_bits);
173  else
174    {
175      fprintf (stderr, "Invalid header/table choice: %s\n", argv[1]);
176      exit (1);
177    }
178
179  return 0;
180}
181