1 /* Generate mpz_fac_ui data.
3 Copyright 2002 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1 of the License, or (at your
10 option) any later version.
12 The GNU MP Library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15 License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
20 MA 02110-1301, USA. */
28 /* sets x=y*(y+2)*(y+4)*....*(y+2*(z-1)) */
30 odd_products (mpz_t x, mpz_t y, int z)
45 /* returns 0 on success */
47 gen_consts (int numb, int nail, int limb)
50 unsigned long a, b, first = 1;
52 printf ("/* This file is automatically generated by gen-fac_ui.c */\n\n");
53 printf ("#if GMP_NUMB_BITS != %d\n", numb);
54 printf ("Error , error this data is for %d GMP_NUMB_BITS only\n", numb);
56 printf ("#if GMP_LIMB_BITS != %d\n", limb);
57 printf ("Error , error this data is for %d GMP_LIMB_BITS only\n", limb);
61 ("/* This table is 0!,1!,2!,3!,...,n! where n! has <= GMP_NUMB_BITS bits */\n");
63 ("#define ONE_LIMB_FACTORIAL_TABLE CNST_LIMB(0x1),CNST_LIMB(0x1),CNST_LIMB(0x2),");
64 mpz_init_set_ui (x, 2);
67 mpz_mul_ui (x, x, b); /* so b!=a */
68 if (mpz_sizeinbase (x, 2) > numb)
78 printf ("CNST_LIMB(0x");
79 mpz_out_str (stdout, 16, x);
85 mpz_mul_2exp (x, x, limb + 1); /* x=2^(limb+1) */
87 mpz_set_ui (y, 10000);
88 mpz_mul (x, x, y); /* x=2^(limb+1)*10^4 */
89 mpz_set_ui (y, 27182); /* exp(1)*10^4 */
90 mpz_tdiv_q (x, x, y); /* x=2^(limb+1)/exp(1) */
91 printf ("\n/* is 2^(GMP_LIMB_BITS+1)/exp(1) */\n");
92 printf ("#define FAC2OVERE CNST_LIMB(0x");
93 mpz_out_str (stdout, 16, x);
98 ("\n/* FACMULn is largest odd x such that x*(x+2)*...*(x+2(n-1))<=2^GMP_NUMB_BITS-1 */\n\n");
101 for (a = 2; a <= 4; a++)
104 mpz_mul_2exp (x, x, numb);
106 /* so x is approx sol */
108 mpz_sub_ui (x, x, 1);
110 mpz_mul_2exp (y, y, numb);
111 mpz_sub_ui (y, y, 1);
112 /* decrement x until we are <= real sol */
115 mpz_sub_ui (x, x, 2);
116 odd_products (t, x, a);
117 if (mpz_cmp (t, y) <= 0)
121 /* increment x until > real sol */
124 mpz_add_ui (x, x, 2);
125 odd_products (t, x, a);
126 if (mpz_cmp (t, y) > 0)
130 /* dec once to get real sol */
131 mpz_sub_ui (x, x, 2);
132 printf ("#define FACMUL%lu CNST_LIMB(0x", a);
133 mpz_out_str (stdout, 16, x);
141 main (int argc, char *argv[])
143 int nail_bits, limb_bits, numb_bits;
147 fprintf (stderr, "Usage: gen-fac_ui limbbits nailbits\n");
150 limb_bits = atoi (argv[1]);
151 nail_bits = atoi (argv[2]);
152 numb_bits = limb_bits - nail_bits;
153 if (limb_bits < 0 || nail_bits < 0 || numb_bits < 0)
155 fprintf (stderr, "Invalid limb/nail bits %d,%d\n", limb_bits,
159 gen_consts (numb_bits, nail_bits, limb_bits);