| /* mpn_add_n -- Add two limb vectors of equal, non-zero length. |
| |
| Copyright (C) 1992, 1993, 1994, 1996 Free Software Foundation, Inc. |
| |
| This file is part of the GNU MP Library. |
| |
| The GNU MP Library is free software; you can redistribute it and/or modify |
| it under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or (at your |
| option) any later version. |
| |
| The GNU MP Library is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
| License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
| the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| MA 02111-1307, USA. */ |
| |
| #include <config.h> |
| #include "gmp-impl.h" |
| |
| mp_limb_t |
| #if __STDC__ |
| mpn_add_n (mp_ptr res_ptr, mp_srcptr s1_ptr, mp_srcptr s2_ptr, mp_size_t size) |
| #else |
| mpn_add_n (res_ptr, s1_ptr, s2_ptr, size) |
| register mp_ptr res_ptr; |
| register mp_srcptr s1_ptr; |
| register mp_srcptr s2_ptr; |
| mp_size_t size; |
| #endif |
| { |
| register mp_limb_t x, y, cy; |
| register mp_size_t j; |
| |
| /* The loop counter and index J goes from -SIZE to -1. This way |
| the loop becomes faster. */ |
| j = -size; |
| |
| /* Offset the base pointers to compensate for the negative indices. */ |
| s1_ptr -= j; |
| s2_ptr -= j; |
| res_ptr -= j; |
| |
| cy = 0; |
| do |
| { |
| y = s2_ptr[j]; |
| x = s1_ptr[j]; |
| y += cy; /* add previous carry to one addend */ |
| cy = (y < cy); /* get out carry from that addition */ |
| y = x + y; /* add other addend */ |
| cy = (y < x) + cy; /* get out carry from that add, combine */ |
| res_ptr[j] = y; |
| } |
| while (++j != 0); |
| |
| return cy; |
| } |