source/libs/gmp/gmp-src/mpz/mul_i.h

   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.h"
  34 #include "gmp-impl.h"
  35
  36
  37 #ifdef OPERATION_mul_si
  38 #define FUNCTION               mpz_mul_si
  39 #define MULTIPLICAND_UNSIGNED
  40 #define MULTIPLICAND_ABS(x)    ABS_CAST(unsigned long, (x))
  41 #endif
  42
  43 #ifdef OPERATION_mul_ui
  44 #define FUNCTION               mpz_mul_ui
  45 #define MULTIPLICAND_UNSIGNED  unsigned
  46 #define MULTIPLICAND_ABS(x)    x
  47 #endif
  48
  49 #ifndef FUNCTION
  50 Error, error, unrecognised OPERATION
  51 #endif
  52
  53
  54 void
  55 FUNCTION (mpz_ptr prod, mpz_srcptr mult,
  56           MULTIPLICAND_UNSIGNED long int small_mult)
  57 {
  58   mp_size_t size;
  59   mp_size_t sign_product;
  60   mp_limb_t sml;
  61   mp_limb_t cy;
  62   mp_ptr pp;
  63
  64   sign_product = SIZ(mult);
  65   if (sign_product == 0 || small_mult == 0)
  66     {
  67       SIZ(prod) = 0;
  68       return;
  69     }
  70
  71   size = ABS (sign_product);
  72
  73   sml = MULTIPLICAND_ABS (small_mult);
  74
  75   if (sml <= GMP_NUMB_MAX)
  76     {
  77       pp = MPZ_REALLOC (prod, size + 1);
  78       cy = mpn_mul_1 (pp, PTR(mult), size, sml);
  79       pp[size] = cy;
  80       size += cy != 0;
  81     }
  82 #if GMP_NAIL_BITS != 0
  83   else
  84     {
  85       /* Operand too large for the current nails size.  Use temporary for
  86          intermediate products, to allow prod and mult being identical.  */
  87       mp_ptr tp;
  88       TMP_DECL;
  89       TMP_MARK;
  90
  91       tp = TMP_ALLOC_LIMBS (size + 2);
  92
  93       /* Use, maybe, mpn_mul_2? */
  94       cy = mpn_mul_1 (tp, PTR(mult), size, sml & GMP_NUMB_MASK);
  95       tp[size] = cy;
  96       cy = mpn_addmul_1 (tp + 1, PTR(mult), size, sml >> GMP_NUMB_BITS);
  97       tp[size + 1] = cy;
  98       size += 2;
  99       MPN_NORMALIZE_NOT_ZERO (tp, size); /* too general, need to trim one or two limb */
 100       pp = MPZ_REALLOC (prod, size);
 101       MPN_COPY (pp, tp, size);
 102       TMP_FREE;
 103     }
 104 #endif
 105
 106   SIZ(prod) = ((sign_product < 0) ^ (small_mult < 0)) ? -size : size;
 107 }