Annotation of OpenXM_contrib/gmp/mpz/fdiv_qr_ui.c, Revision 1.1.1.3
1.1 maekawa 1: /* mpz_fdiv_qr_ui -- Division rounding the quotient towards -infinity.
2: The remainder gets the same sign as the denominator.
3:
1.1.1.3 ! ohara 4: Copyright 1994, 1995, 1996, 1999, 2001, 2002 Free Software Foundation, Inc.
1.1 maekawa 5:
6: This file is part of the GNU MP Library.
7:
8: The GNU MP Library is free software; you can redistribute it and/or modify
1.1.1.2 maekawa 9: it under the terms of the GNU Lesser General Public License as published by
10: the Free Software Foundation; either version 2.1 of the License, or (at your
1.1 maekawa 11: option) any later version.
12:
13: The GNU MP Library is distributed in the hope that it will be useful, but
14: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
1.1.1.2 maekawa 15: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
1.1 maekawa 16: License for more details.
17:
1.1.1.2 maekawa 18: You should have received a copy of the GNU Lesser General Public License
1.1 maekawa 19: along with the GNU MP Library; see the file COPYING.LIB. If not, write to
20: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
21: MA 02111-1307, USA. */
22:
23: #include "gmp.h"
24: #include "gmp-impl.h"
25:
26: unsigned long int
27: mpz_fdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor)
28: {
1.1.1.3 ! ohara 29: mp_size_t ns, nn, qn;
! 30: mp_ptr np, qp;
! 31: mp_limb_t rl;
1.1 maekawa 32:
1.1.1.2 maekawa 33: if (divisor == 0)
34: DIVIDE_BY_ZERO;
35:
1.1.1.3 ! ohara 36: ns = SIZ(dividend);
! 37: if (ns == 0)
1.1 maekawa 38: {
1.1.1.3 ! ohara 39: SIZ(quot) = 0;
! 40: SIZ(rem) = 0;
! 41: return 0;
1.1 maekawa 42: }
43:
1.1.1.3 ! ohara 44: nn = ABS(ns);
! 45: MPZ_REALLOC (quot, nn);
! 46: qp = PTR(quot);
! 47: np = PTR(dividend);
1.1 maekawa 48:
1.1.1.3 ! ohara 49: #if GMP_NAIL_BITS != 0
! 50: if (divisor > GMP_NUMB_MAX)
! 51: {
! 52: mp_limb_t dp[2];
! 53: mp_ptr rp;
! 54: mp_size_t rn;
! 55:
! 56: MPZ_REALLOC (rem, 2);
! 57: rp = PTR(rem);
! 58:
! 59: if (nn == 1) /* tdiv_qr requirements; tested above for 0 */
! 60: {
! 61: qp[0] = 0;
! 62: qn = 1; /* a white lie, fixed below */
! 63: rl = np[0];
! 64: rp[0] = rl;
! 65: }
! 66: else
! 67: {
! 68: dp[0] = divisor & GMP_NUMB_MASK;
! 69: dp[1] = divisor >> GMP_NUMB_BITS;
! 70: mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2);
! 71: rl = rp[0] + (rp[1] << GMP_NUMB_BITS);
! 72: qn = nn - 2 + 1;
! 73: }
! 74:
! 75: if (rl != 0 && ns < 0)
! 76: {
! 77: mpn_incr_u (qp, (mp_limb_t) 1);
! 78: rl = divisor - rl;
! 79: rp[0] = rl & GMP_NUMB_MASK;
! 80: rp[1] = rl >> GMP_NUMB_BITS;
! 81: }
! 82:
! 83: qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0;
! 84: rn = 1 + (rl > GMP_NUMB_MAX); rn -= (rp[rn - 1] == 0);
! 85: SIZ(rem) = rn;
! 86: }
! 87: else
! 88: #endif
! 89: {
! 90: rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor);
! 91: if (rl == 0)
! 92: SIZ(rem) = 0;
! 93: else
! 94: {
! 95: if (ns < 0)
! 96: {
! 97: mpn_incr_u (qp, (mp_limb_t) 1);
! 98: rl = divisor - rl;
! 99: }
! 100:
! 101: PTR(rem)[0] = rl;
! 102: SIZ(rem) = rl != 0;
! 103: }
! 104: qn = nn - (qp[nn - 1] == 0);
! 105: }
1.1 maekawa 106:
1.1.1.3 ! ohara 107: SIZ(quot) = ns >= 0 ? qn : -qn;
! 108: return rl;
1.1 maekawa 109: }
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