| /* mpn_sub_n -- Subtract equal length limb vectors. |
| |
| Copyright 1992, 1993, 1994, 1996, 2000, 2002 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 3 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. If not, see http://www.gnu.org/licenses/. */ |
| |
| #include "gmp.h" |
| #include "gmp-impl.h" |
| |
| |
| #if GMP_NAIL_BITS == 0 |
| |
| mp_limb_t |
| mpn_sub_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp, mp_size_t n) |
| { |
| mp_limb_t ul, vl, sl, rl, cy, cy1, cy2; |
| |
| ASSERT (n >= 1); |
| ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); |
| ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n)); |
| |
| cy = 0; |
| do |
| { |
| ul = *up++; |
| vl = *vp++; |
| sl = ul - vl; |
| cy1 = sl > ul; |
| rl = sl - cy; |
| cy2 = rl > sl; |
| cy = cy1 | cy2; |
| *rp++ = rl; |
| } |
| while (--n != 0); |
| |
| return cy; |
| } |
| |
| #endif |
| |
| #if GMP_NAIL_BITS >= 1 |
| |
| mp_limb_t |
| mpn_sub_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp, mp_size_t n) |
| { |
| mp_limb_t ul, vl, rl, cy; |
| |
| ASSERT (n >= 1); |
| ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); |
| ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n)); |
| |
| cy = 0; |
| do |
| { |
| ul = *up++; |
| vl = *vp++; |
| rl = ul - vl - cy; |
| cy = rl >> (GMP_LIMB_BITS - 1); |
| *rp++ = rl & GMP_NUMB_MASK; |
| } |
| while (--n != 0); |
| |
| return cy; |
| } |
| |
| #endif |