1 /* mpn_sub_n -- Subtract equal length limb vectors. 2 3 Copyright 1992, 1993, 1994, 1996, 2000, 2002 Free Software Foundation, Inc. 4 5 This file is part of the GNU MP Library. 6 7 The GNU MP Library is free software; you can redistribute it and/or modify 8 it under the terms of the GNU Lesser General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or (at your 10 option) any later version. 11 12 The GNU MP Library is distributed in the hope that it will be useful, but 13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 15 License for more details. 16 17 You should have received a copy of the GNU Lesser General Public License 18 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */ 19 20 #include "gmp.h" 21 #include "gmp-impl.h" 22 23 24 #if GMP_NAIL_BITS == 0 25 26 mp_limb_t 27 mpn_sub_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp, mp_size_t n) 28 { 29 mp_limb_t ul, vl, sl, rl, cy, cy1, cy2; 30 31 ASSERT (n >= 1); 32 ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); 33 ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n)); 34 35 cy = 0; 36 do 37 { 38 ul = *up++; 39 vl = *vp++; 40 sl = ul - vl; 41 cy1 = sl > ul; 42 rl = sl - cy; 43 cy2 = rl > sl; 44 cy = cy1 | cy2; 45 *rp++ = rl; 46 } 47 while (--n != 0); 48 49 return cy; 50 } 51 52 #endif 53 54 #if GMP_NAIL_BITS >= 1 55 56 mp_limb_t 57 mpn_sub_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp, mp_size_t n) 58 { 59 mp_limb_t ul, vl, rl, cy; 60 61 ASSERT (n >= 1); 62 ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); 63 ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n)); 64 65 cy = 0; 66 do 67 { 68 ul = *up++; 69 vl = *vp++; 70 rl = ul - vl - cy; 71 cy = rl >> (GMP_LIMB_BITS - 1); 72 *rp++ = rl & GMP_NUMB_MASK; 73 } 74 while (--n != 0); 75 76 return cy; 77 } 78 79 #endif 80