1  /* mpz_mul_ui/si (product, multiplier, small_multiplicand) -- Set PRODUCT to
       2     MULTIPLICATOR times SMALL_MULTIPLICAND.
       3  
       4  Copyright 1991, 1993, 1994, 1996, 2000-2002, 2005, 2008, 2012 Free Software
       5  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 either:
      11  
      12    * the GNU Lesser General Public License as published by the Free
      13      Software Foundation; either version 3 of the License, or (at your
      14      option) any later version.
      15  
      16  or
      17  
      18    * the GNU General Public License as published by the Free Software
      19      Foundation; either version 2 of the License, or (at your option) any
      20      later version.
      21  
      22  or both in parallel, as here.
      23  
      24  The GNU MP Library is distributed in the hope that it will be useful, but
      25  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      26  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      27  for more details.
      28  
      29  You should have received copies of the GNU General Public License and the
      30  GNU Lesser General Public License along with the GNU MP Library.  If not,
      31  see https://www.gnu.org/licenses/.  */
      32  
      33  #include "gmp-impl.h"
      34  
      35  
      36  #ifdef OPERATION_mul_si
      37  #define FUNCTION               mpz_mul_si
      38  #define MULTIPLICAND_UNSIGNED
      39  #define MULTIPLICAND_ABS(x)    ABS_CAST(unsigned long, (x))
      40  #endif
      41  
      42  #ifdef OPERATION_mul_ui
      43  #define FUNCTION               mpz_mul_ui
      44  #define MULTIPLICAND_UNSIGNED  unsigned
      45  #define MULTIPLICAND_ABS(x)    x
      46  #endif
      47  
      48  #ifndef FUNCTION
      49  Error, error, unrecognised OPERATION
      50  #endif
      51  
      52  
      53  void
      54  FUNCTION (mpz_ptr prod, mpz_srcptr mult,
      55            MULTIPLICAND_UNSIGNED long int small_mult)
      56  {
      57    mp_size_t size;
      58    mp_size_t sign_product;
      59    mp_limb_t sml;
      60    mp_limb_t cy;
      61    mp_ptr pp;
      62  
      63    sign_product = SIZ(mult);
      64    if (sign_product == 0 || small_mult == 0)
      65      {
      66        SIZ(prod) = 0;
      67        return;
      68      }
      69  
      70    size = ABS (sign_product);
      71  
      72    sml = MULTIPLICAND_ABS (small_mult);
      73  
      74    if (sml <= GMP_NUMB_MAX)
      75      {
      76        pp = MPZ_REALLOC (prod, size + 1);
      77        cy = mpn_mul_1 (pp, PTR(mult), size, sml);
      78        pp[size] = cy;
      79        size += cy != 0;
      80      }
      81  #if GMP_NAIL_BITS != 0
      82    else
      83      {
      84        /* Operand too large for the current nails size.  Use temporary for
      85  	 intermediate products, to allow prod and mult being identical.  */
      86        mp_ptr tp;
      87        TMP_DECL;
      88        TMP_MARK;
      89  
      90        tp = TMP_ALLOC_LIMBS (size + 2);
      91  
      92        /* Use, maybe, mpn_mul_2? */
      93        cy = mpn_mul_1 (tp, PTR(mult), size, sml & GMP_NUMB_MASK);
      94        tp[size] = cy;
      95        cy = mpn_addmul_1 (tp + 1, PTR(mult), size, sml >> GMP_NUMB_BITS);
      96        tp[size + 1] = cy;
      97        size += 2;
      98        MPN_NORMALIZE_NOT_ZERO (tp, size); /* too general, need to trim one or two limb */
      99        pp = MPZ_NEWALLOC (prod, size);
     100        MPN_COPY (pp, tp, size);
     101        TMP_FREE;
     102      }
     103  #endif
     104  
     105    SIZ(prod) = ((sign_product < 0) ^ (small_mult < 0)) ? -size : size;
     106  }