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Annotation of OpenXM_contrib/gmp/mpz/tdiv_qr_ui.c, Revision 1.1

1.1     ! maekawa     1: /* mpz_tdiv_qr_ui(quot,rem,dividend,short_divisor) --
        !             2:    Set QUOT to DIVIDEND / SHORT_DIVISOR
        !             3:    and REM to DIVIDEND mod SHORT_DIVISOR.
        !             4:
        !             5: Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
        !             6:
        !             7: This file is part of the GNU MP Library.
        !             8:
        !             9: The GNU MP Library is free software; you can redistribute it and/or modify
        !            10: it under the terms of the GNU Library General Public License as published by
        !            11: the Free Software Foundation; either version 2 of the License, or (at your
        !            12: option) any later version.
        !            13:
        !            14: The GNU MP Library is distributed in the hope that it will be useful, but
        !            15: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            16: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
        !            17: License for more details.
        !            18:
        !            19: You should have received a copy of the GNU Library General Public License
        !            20: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            21: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            22: MA 02111-1307, USA. */
        !            23:
        !            24: #include "gmp.h"
        !            25: #include "gmp-impl.h"
        !            26:
        !            27: void
        !            28: #if __STDC__
        !            29: mpz_tdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor)
        !            30: #else
        !            31: mpz_tdiv_qr_ui (quot, rem, dividend, divisor)
        !            32:      mpz_ptr quot;
        !            33:      mpz_ptr rem;
        !            34:      mpz_srcptr dividend;
        !            35:      unsigned long int divisor;
        !            36: #endif
        !            37: {
        !            38:   mp_size_t dividend_size;
        !            39:   mp_size_t size;
        !            40:   mp_ptr quot_ptr;
        !            41:   mp_limb_t remainder_limb;
        !            42:
        !            43:   dividend_size = dividend->_mp_size;
        !            44:   size = ABS (dividend_size);
        !            45:
        !            46:   if (size == 0)
        !            47:     {
        !            48:       quot->_mp_size = 0;
        !            49:       rem->_mp_size = 0;
        !            50:       return;
        !            51:     }
        !            52:
        !            53:   /* No need for temporary allocation and copying if QUOT == DIVIDEND as
        !            54:      the divisor is just one limb, and thus no intermediate remainders
        !            55:      need to be stored.  */
        !            56:
        !            57:   if (quot->_mp_alloc < size)
        !            58:     _mpz_realloc (quot, size);
        !            59:
        !            60:   quot_ptr = quot->_mp_d;
        !            61:
        !            62:   remainder_limb = mpn_divmod_1 (quot_ptr, dividend->_mp_d, size,
        !            63:                                   (mp_limb_t) divisor);
        !            64:
        !            65:   if (remainder_limb == 0)
        !            66:     rem->_mp_size = 0;
        !            67:   else
        !            68:     {
        !            69:       /* Store the single-limb remainder.  We don't check if there's space
        !            70:         for just one limb, since no function ever makes zero space.  */
        !            71:       rem->_mp_size = dividend_size >= 0 ? 1 : -1;
        !            72:       rem->_mp_d[0] = remainder_limb;
        !            73:     }
        !            74:
        !            75:   /* The quotient is SIZE limbs, but the most significant might be zero. */
        !            76:   size -= quot_ptr[size - 1] == 0;
        !            77:   quot->_mp_size = dividend_size >= 0 ? size : -size;
        !            78: }