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comparison bn_mp_karatsuba_mul.c @ 142:d29b64170cf0 libtommath-orig

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import of libtommath 0.32
author Matt Johnston <matt@ucc.asn.au>
date Sun, 19 Dec 2004 11:33:56 +0000
parents 86e0b50a9b58
children
comparison
equal deleted inserted replaced
19:e1037a1e12e7 142:d29b64170cf0
1 #include <tommath.h>
2 #ifdef BN_MP_KARATSUBA_MUL_C
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 * 4 *
3 * LibTomMath is a library that provides multiple-precision 5 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality. 6 * integer arithmetic as well as number theoretic functionality.
5 * 7 *
10 * The library is free for all purposes without any express 12 * The library is free for all purposes without any express
11 * guarantee it works. 13 * guarantee it works.
12 * 14 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org 15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */ 16 */
15 #include <tommath.h>
16 17
17 /* c = |a| * |b| using Karatsuba Multiplication using 18 /* c = |a| * |b| using Karatsuba Multiplication using
18 * three half size multiplications 19 * three half size multiplications
19 * 20 *
20 * Let B represent the radix [e.g. 2**DIGIT_BIT] and 21 * Let B represent the radix [e.g. 2**DIGIT_BIT] and
74 goto T1; 75 goto T1;
75 if (mp_init_size (&x1y1, B * 2) != MP_OKAY) 76 if (mp_init_size (&x1y1, B * 2) != MP_OKAY)
76 goto X0Y0; 77 goto X0Y0;
77 78
78 /* now shift the digits */ 79 /* now shift the digits */
79 x0.sign = x1.sign = a->sign;
80 y0.sign = y1.sign = b->sign;
81
82 x0.used = y0.used = B; 80 x0.used = y0.used = B;
83 x1.used = a->used - B; 81 x1.used = a->used - B;
84 y1.used = b->used - B; 82 y1.used = b->used - B;
85 83
86 { 84 {
160 X1:mp_clear (&x1); 158 X1:mp_clear (&x1);
161 X0:mp_clear (&x0); 159 X0:mp_clear (&x0);
162 ERR: 160 ERR:
163 return err; 161 return err;
164 } 162 }
163 #endif