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1 /* mpn_submul_1 -- multiply the S1_SIZE long limb vector pointed to by S1_PTR
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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2 by S2_LIMB, subtract the S1_SIZE least significant limbs of the product
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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3 from the limb vector pointed to by RES_PTR. Return the most significant
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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4 limb of the product, adjusted for carry-out from the subtraction.
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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5
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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6 Copyright (C) 1992, 1993, 1994, 1996, 2005 Free Software Foundation, Inc.
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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7
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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8 This file is part of the GNU MP Library.
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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9
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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10 The GNU MP Library is free software; you can redistribute it and/or modify
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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11 it under the terms of the GNU Lesser General Public License as published by
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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12 the Free Software Foundation; either version 2.1 of the License, or (at your
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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13 option) any later version.
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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14
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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15 The GNU MP Library is distributed in the hope that it will be useful, but
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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16 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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17 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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18 License for more details.
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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19
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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20 You should have received a copy of the GNU Lesser General Public License
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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21 along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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22 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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23 MA 02111-1307, USA. */
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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24
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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25 #include <config.h>
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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26 #include "gmp-impl.h"
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27
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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28 mp_limb_t
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29 mpn_submul_1 (res_ptr, s1_ptr, s1_size, s2_limb)
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30 register mp_ptr res_ptr;
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31 register mp_srcptr s1_ptr;
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32 mp_size_t s1_size;
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33 register mp_limb_t s2_limb;
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34 {
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35 register mp_limb_t cy_limb;
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36 register mp_size_t j;
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37 register mp_limb_t prod_high, prod_low;
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38 register mp_limb_t x;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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39
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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40 /* The loop counter and index J goes from -SIZE to -1. This way
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41 the loop becomes faster. */
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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42 j = -s1_size;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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43
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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44 /* Offset the base pointers to compensate for the negative indices. */
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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45 res_ptr -= j;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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46 s1_ptr -= j;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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47
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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48 cy_limb = 0;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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49 do
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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50 {
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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51 umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb);
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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52
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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53 prod_low += cy_limb;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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54 cy_limb = (prod_low < cy_limb) + prod_high;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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55
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
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56 x = res_ptr[j];
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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57 prod_low = x - prod_low;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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58 cy_limb += (prod_low > x);
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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59 res_ptr[j] = prod_low;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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60 }
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
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61 while (++j != 0);
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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62
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
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63 return cy_limb;
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Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
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64 }
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