Mercurial > dropbear
annotate bn_mp_lcm.c @ 190:d8254fc979e9 libtommath-orig LTM_0.35
Initial import of libtommath 0.35
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Fri, 06 May 2005 08:59:30 +0000 |
| parents | d29b64170cf0 |
| children |
| rev | line source |
|---|---|
| 142 | 1 #include <tommath.h> |
| 2 #ifdef BN_MP_LCM_C | |
| 2 | 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
| 4 * | |
| 5 * LibTomMath is a library that provides multiple-precision | |
| 6 * integer arithmetic as well as number theoretic functionality. | |
| 7 * | |
| 8 * The library was designed directly after the MPI library by | |
| 9 * Michael Fromberger but has been written from scratch with | |
| 10 * additional optimizations in place. | |
| 11 * | |
| 12 * The library is free for all purposes without any express | |
| 13 * guarantee it works. | |
| 14 * | |
| 15 * Tom St Denis, [email protected], http://math.libtomcrypt.org | |
| 16 */ | |
| 17 | |
| 18 /* computes least common multiple as |a*b|/(a, b) */ | |
| 19 int mp_lcm (mp_int * a, mp_int * b, mp_int * c) | |
| 20 { | |
| 21 int res; | |
| 22 mp_int t1, t2; | |
| 23 | |
| 24 | |
| 25 if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) { | |
| 26 return res; | |
| 27 } | |
| 28 | |
| 29 /* t1 = get the GCD of the two inputs */ | |
| 30 if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) { | |
|
190
d8254fc979e9
Initial import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
142
diff
changeset
|
31 goto LBL_T; |
| 2 | 32 } |
| 33 | |
| 34 /* divide the smallest by the GCD */ | |
| 35 if (mp_cmp_mag(a, b) == MP_LT) { | |
| 36 /* store quotient in t2 such that t2 * b is the LCM */ | |
| 37 if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) { | |
|
190
d8254fc979e9
Initial import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
142
diff
changeset
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38 goto LBL_T; |
| 2 | 39 } |
| 40 res = mp_mul(b, &t2, c); | |
| 41 } else { | |
| 42 /* store quotient in t2 such that t2 * a is the LCM */ | |
| 43 if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) { | |
|
190
d8254fc979e9
Initial import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
142
diff
changeset
|
44 goto LBL_T; |
| 2 | 45 } |
| 46 res = mp_mul(a, &t2, c); | |
| 47 } | |
| 48 | |
| 49 /* fix the sign to positive */ | |
| 50 c->sign = MP_ZPOS; | |
| 51 | |
|
190
d8254fc979e9
Initial import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
142
diff
changeset
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52 LBL_T: |
| 2 | 53 mp_clear_multi (&t1, &t2, NULL); |
| 54 return res; | |
| 55 } | |
| 142 | 56 #endif |