1 | /* mpz_lcm_ui -- least common multiple of mpz and ulong. |
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2 | |
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3 | Copyright 2001, 2002 Free Software Foundation, Inc. |
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4 | |
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5 | This file is part of the GNU MP Library. |
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6 | |
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7 | The GNU MP Library is free software; you can redistribute it and/or modify |
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8 | it under the terms of the GNU Lesser General Public License as published by |
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9 | the Free Software Foundation; either version 2.1 of the License, or (at your |
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10 | option) any later version. |
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11 | |
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12 | The GNU MP Library is distributed in the hope that it will be useful, but |
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13 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
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14 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
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15 | License for more details. |
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16 | |
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17 | You should have received a copy of the GNU Lesser General Public License |
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18 | along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
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19 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
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20 | MA 02111-1307, USA. */ |
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21 | |
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22 | #include "gmp.h" |
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23 | #include "gmp-impl.h" |
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24 | #include "longlong.h" |
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25 | |
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26 | |
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27 | void |
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28 | mpz_lcm_ui (mpz_ptr r, mpz_srcptr u, unsigned long v) |
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29 | { |
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30 | mp_size_t usize; |
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31 | mp_srcptr up; |
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32 | mp_ptr rp; |
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33 | unsigned long g; |
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34 | mp_limb_t c; |
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35 | |
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36 | #if GMP_NAIL_BITS != 0 |
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37 | if (v > GMP_NUMB_MAX) |
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38 | { |
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39 | mpz_t vz; |
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40 | mp_limb_t vlimbs[2]; |
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41 | vlimbs[0] = v & GMP_NUMB_MASK; |
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42 | vlimbs[1] = v >> GMP_NUMB_BITS; |
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43 | PTR(vz) = vlimbs; |
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44 | SIZ(vz) = 2; |
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45 | mpz_lcm (r, u, vz); |
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46 | return; |
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47 | } |
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48 | #endif |
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49 | |
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50 | /* result zero if either operand zero */ |
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51 | usize = SIZ(u); |
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52 | if (usize == 0 || v == 0) |
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53 | { |
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54 | SIZ(r) = 0; |
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55 | return; |
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56 | } |
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57 | usize = ABS(usize); |
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58 | |
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59 | MPZ_REALLOC (r, usize+1); |
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60 | |
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61 | up = PTR(u); |
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62 | g = (unsigned long) mpn_gcd_1 (up, usize, (mp_limb_t) v); |
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63 | v /= g; |
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64 | |
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65 | rp = PTR(r); |
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66 | c = mpn_mul_1 (rp, up, usize, (mp_limb_t) v); |
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67 | rp[usize] = c; |
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68 | usize += (c != 0); |
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69 | SIZ(r) = usize; |
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70 | } |
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