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Annotation of OpenXM_contrib/gmp/mpz/mod.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpz_mod -- The mathematical mod function.
                      2:
                      3: Copyright (C) 1991, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
                      4:
                      5: This file is part of the GNU MP Library.
                      6:
                      7: The GNU MP Library is free software; you can redistribute it and/or modify
                      8: it under the terms of the GNU Library General Public License as published by
                      9: the Free Software Foundation; either version 2 of the License, or (at your
                     10: option) any later version.
                     11:
                     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 Library General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Library 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., 59 Temple Place - Suite 330, Boston,
                     20: MA 02111-1307, USA. */
                     21:
                     22: #include "gmp.h"
                     23: #include "gmp-impl.h"
                     24:
                     25: void
                     26: #if __STDC__
                     27: mpz_mod (mpz_ptr rem, mpz_srcptr dividend, mpz_srcptr divisor)
                     28: #else
                     29: mpz_mod (rem, dividend, divisor)
                     30:      mpz_ptr rem;
                     31:      mpz_srcptr dividend;
                     32:      mpz_srcptr divisor;
                     33: #endif
                     34: {
                     35:   mp_size_t divisor_size = divisor->_mp_size;
                     36:   mpz_t temp_divisor;          /* N.B.: lives until function returns! */
                     37:   TMP_DECL (marker);
                     38:
                     39:   TMP_MARK (marker);
                     40:
                     41:   /* We need the original value of the divisor after the remainder has been
                     42:      preliminary calculated.  We have to copy it to temporary space if it's
                     43:      the same variable as REM.  */
                     44:   if (rem == divisor)
                     45:     {
                     46:       MPZ_TMP_INIT (temp_divisor, ABS (divisor_size));
                     47:       mpz_set (temp_divisor, divisor);
                     48:       divisor = temp_divisor;
                     49:     }
                     50:
                     51:   mpz_tdiv_r (rem, dividend, divisor);
                     52:
                     53:   if (rem->_mp_size != 0)
                     54:     {
                     55:       if (dividend->_mp_size < 0)
                     56:        if (divisor->_mp_size < 0)
                     57:          mpz_sub (rem, rem, divisor);
                     58:        else
                     59:          mpz_add (rem, rem, divisor);
                     60:     }
                     61:
                     62:   TMP_FREE (marker);
                     63: }