1*627f7eb2Smrg /* mpn_addmul_1 -- multiply the S1_SIZE long limb vector pointed to by S1_PTR
2*627f7eb2Smrg by S2_LIMB, add the S1_SIZE least significant limbs of the product to the
3*627f7eb2Smrg limb vector pointed to by RES_PTR. Return the most significant limb of
4*627f7eb2Smrg the product, adjusted for carry-out from the addition.
5*627f7eb2Smrg
6*627f7eb2Smrg Copyright (C) 1992, 1993, 1994, 1996 Free Software Foundation, Inc.
7*627f7eb2Smrg
8*627f7eb2Smrg This file is part of the GNU MP Library.
9*627f7eb2Smrg
10*627f7eb2Smrg The GNU MP Library is free software; you can redistribute it and/or modify
11*627f7eb2Smrg it under the terms of the GNU Lesser General Public License as published by
12*627f7eb2Smrg the Free Software Foundation; either version 2.1 of the License, or (at your
13*627f7eb2Smrg option) any later version.
14*627f7eb2Smrg
15*627f7eb2Smrg The GNU MP Library is distributed in the hope that it will be useful, but
16*627f7eb2Smrg WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
17*627f7eb2Smrg or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
18*627f7eb2Smrg License for more details.
19*627f7eb2Smrg
20*627f7eb2Smrg You should have received a copy of the GNU Lesser General Public License
21*627f7eb2Smrg along with the GNU MP Library; see the file COPYING.LIB. If not, write to
22*627f7eb2Smrg the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
23*627f7eb2Smrg MA 02111-1307, USA. */
24*627f7eb2Smrg
25*627f7eb2Smrg #include <config.h>
26*627f7eb2Smrg #include "gmp-impl.h"
27*627f7eb2Smrg
28*627f7eb2Smrg mp_limb_t
mpn_addmul_1(res_ptr,s1_ptr,s1_size,s2_limb)29*627f7eb2Smrg mpn_addmul_1 (res_ptr, s1_ptr, s1_size, s2_limb)
30*627f7eb2Smrg register mp_ptr res_ptr;
31*627f7eb2Smrg register mp_srcptr s1_ptr;
32*627f7eb2Smrg mp_size_t s1_size;
33*627f7eb2Smrg register mp_limb_t s2_limb;
34*627f7eb2Smrg {
35*627f7eb2Smrg register mp_limb_t cy_limb;
36*627f7eb2Smrg register mp_size_t j;
37*627f7eb2Smrg register mp_limb_t prod_high, prod_low;
38*627f7eb2Smrg register mp_limb_t x;
39*627f7eb2Smrg
40*627f7eb2Smrg /* The loop counter and index J goes from -SIZE to -1. This way
41*627f7eb2Smrg the loop becomes faster. */
42*627f7eb2Smrg j = -s1_size;
43*627f7eb2Smrg
44*627f7eb2Smrg /* Offset the base pointers to compensate for the negative indices. */
45*627f7eb2Smrg res_ptr -= j;
46*627f7eb2Smrg s1_ptr -= j;
47*627f7eb2Smrg
48*627f7eb2Smrg cy_limb = 0;
49*627f7eb2Smrg do
50*627f7eb2Smrg {
51*627f7eb2Smrg umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb);
52*627f7eb2Smrg
53*627f7eb2Smrg prod_low += cy_limb;
54*627f7eb2Smrg cy_limb = (prod_low < cy_limb) + prod_high;
55*627f7eb2Smrg
56*627f7eb2Smrg x = res_ptr[j];
57*627f7eb2Smrg prod_low = x + prod_low;
58*627f7eb2Smrg cy_limb += (prod_low < x);
59*627f7eb2Smrg res_ptr[j] = prod_low;
60*627f7eb2Smrg }
61*627f7eb2Smrg while (++j != 0);
62*627f7eb2Smrg
63*627f7eb2Smrg return cy_limb;
64*627f7eb2Smrg }
65