version 1.1, 2000/01/10 15:35:27 |
version 1.1.1.3, 2003/08/25 16:06:33 |
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/* mpz_gcd_ui -- Calculate the greatest common divisior of two integers. |
/* mpz_gcd_ui -- Calculate the greatest common divisior of two integers. |
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Copyright (C) 1994, 1996 Free Software Foundation, Inc. |
Copyright 1994, 1996, 1999, 2000, 2001, 2002 Free Software Foundation, Inc. |
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This file is part of the GNU MP Library. |
This file is part of the GNU MP Library. |
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The GNU MP Library is free software; you can redistribute it and/or modify |
The GNU MP Library is free software; you can redistribute it and/or modify |
it under the terms of the GNU Library General Public License as published by |
it under the terms of the GNU Lesser General Public License as published by |
the Free Software Foundation; either version 2 of the License, or (at your |
the Free Software Foundation; either version 2.1 of the License, or (at your |
option) any later version. |
option) any later version. |
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The GNU MP Library is distributed in the hope that it will be useful, but |
The GNU MP Library is distributed in the hope that it will be useful, but |
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
License for more details. |
License for more details. |
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You should have received a copy of the GNU Library General Public License |
You should have received a copy of the GNU Lesser General Public License |
along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
MA 02111-1307, USA. */ |
MA 02111-1307, USA. */ |
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#include <stdio.h> /* for NULL */ |
#include "gmp.h" |
#include "gmp.h" |
#include "gmp-impl.h" |
#include "gmp-impl.h" |
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unsigned long int |
unsigned long int |
#if __STDC__ |
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mpz_gcd_ui (mpz_ptr w, mpz_srcptr u, unsigned long int v) |
mpz_gcd_ui (mpz_ptr w, mpz_srcptr u, unsigned long int v) |
#else |
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mpz_gcd_ui (w, u, v) |
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mpz_ptr w; |
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mpz_srcptr u; |
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unsigned long int v; |
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#endif |
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{ |
{ |
mp_size_t size; |
mp_size_t un; |
mp_limb_t res; |
mp_limb_t res; |
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size = ABS (u->_mp_size); |
#if GMP_NAIL_BITS != 0 |
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if (v > GMP_NUMB_MAX) |
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{ |
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mpz_t vz; |
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mp_limb_t vlimbs[2]; |
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vlimbs[0] = v & GMP_NUMB_MASK; |
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vlimbs[1] = v >> GMP_NUMB_BITS; |
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PTR(vz) = vlimbs; |
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SIZ(vz) = 2; |
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mpz_gcd (w, u, vz); |
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return; |
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} |
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#endif |
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if (size == 0) |
un = ABSIZ(u); |
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if (un == 0) |
res = v; |
res = v; |
else if (v == 0) |
else if (v == 0) |
{ |
{ |
if (w != NULL && u != w) |
if (w != NULL) |
{ |
{ |
if (w->_mp_alloc < size) |
if (u != w) |
_mpz_realloc (w, size); |
{ |
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MPZ_REALLOC (w, un); |
MPN_COPY (w->_mp_d, u->_mp_d, size); |
MPN_COPY (PTR(w), PTR(u), un); |
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} |
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SIZ(w) = un; |
} |
} |
w->_mp_size = size; |
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/* We can't return any useful result for gcd(big,0). */ |
/* We can't return any useful result for gcd(big,0). */ |
return size > 1 ? 0 : w->_mp_d[0]; |
return un > 1 ? 0 : PTR(u)[0]; |
} |
} |
else |
else |
res = mpn_gcd_1 (u->_mp_d, size, v); |
res = mpn_gcd_1 (PTR(u), un, (mp_limb_t) v); |
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if (w != NULL) |
if (w != NULL) |
{ |
{ |
w->_mp_d[0] = res; |
PTR(w)[0] = res; |
w->_mp_size = 1; |
SIZ(w) = res != 0; |
} |
} |
return res; |
return res; |
} |
} |