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Diffstat (limited to 'REORG.TODO/stdlib/add_n.c')
-rw-r--r-- | REORG.TODO/stdlib/add_n.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/REORG.TODO/stdlib/add_n.c b/REORG.TODO/stdlib/add_n.c new file mode 100644 index 0000000000..12ded53c58 --- /dev/null +++ b/REORG.TODO/stdlib/add_n.c @@ -0,0 +1,53 @@ +/* mpn_add_n -- Add two limb vectors of equal, non-zero length. + +Copyright (C) 1992-2017 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, see +<http://www.gnu.org/licenses/>. */ + +#include <gmp.h> +#include "gmp-impl.h" + +mp_limb_t +mpn_add_n (mp_ptr res_ptr, mp_srcptr s1_ptr, mp_srcptr s2_ptr, mp_size_t size) +{ + 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; +} |