1/* mpn_mul_1 -- Multiply a limb vector with a single limb and 2 store the product in a second limb vector. 3 4Copyright (C) 1991, 1992, 1993, 1994, 1996 Free Software Foundation, Inc. 5 6This file is part of the GNU MP Library. 7 8The GNU MP Library is free software; you can redistribute it and/or modify 9it under the terms of the GNU Library General Public License as published by 10the Free Software Foundation; either version 2 of the License, or (at your 11option) any later version. 12 13The GNU MP Library is distributed in the hope that it will be useful, but 14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 15or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public 16License for more details. 17 18You should have received a copy of the GNU Library General Public License 19along with the GNU MP Library; see the file COPYING.LIB. If not, write to 20the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, 21MA 02111-1307, USA. */ 22 23#include "gmp.h" 24#include "gmp-impl.h" 25#include "longlong.h" 26 27mp_limb_t 28mpn_mul_1 (res_ptr, s1_ptr, s1_size, s2_limb) 29 register mp_ptr res_ptr; 30 register mp_srcptr s1_ptr; 31 mp_size_t s1_size; 32 register mp_limb_t s2_limb; 33{ 34 register mp_limb_t cy_limb; 35 register mp_size_t j; 36 register mp_limb_t prod_high, prod_low; 37 38 /* The loop counter and index J goes from -S1_SIZE to -1. This way 39 the loop becomes faster. */ 40 j = -s1_size; 41 42 /* Offset the base pointers to compensate for the negative indices. */ 43 s1_ptr -= j; 44 res_ptr -= j; 45 46 cy_limb = 0; 47 do 48 { 49 umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb); 50 51 prod_low += cy_limb; 52 cy_limb = (prod_low < cy_limb) + prod_high; 53 54 res_ptr[j] = prod_low; 55 } 56 while (++j != 0); 57 58 return cy_limb; 59} 60