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Diffstat (limited to 'sysdeps/generic/addmul_1.c')
-rw-r--r-- | sysdeps/generic/addmul_1.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/sysdeps/generic/addmul_1.c b/sysdeps/generic/addmul_1.c new file mode 100644 index 0000000..746ae31 --- /dev/null +++ b/sysdeps/generic/addmul_1.c @@ -0,0 +1,65 @@ +/* mpn_addmul_1 -- multiply the S1_SIZE long limb vector pointed to by S1_PTR + by S2_LIMB, add the S1_SIZE least significant limbs of the product to the + limb vector pointed to by RES_PTR. Return the most significant limb of + the product, adjusted for carry-out from the addition. + +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 "gmp.h" +#include "gmp-impl.h" +#include "longlong.h" + +mp_limb_t +mpn_addmul_1 (res_ptr, s1_ptr, s1_size, s2_limb) + register mp_ptr res_ptr; + register mp_srcptr s1_ptr; + mp_size_t s1_size; + register mp_limb_t s2_limb; +{ + register mp_limb_t cy_limb; + register mp_size_t j; + register mp_limb_t prod_high, prod_low; + register mp_limb_t x; + + /* The loop counter and index J goes from -SIZE to -1. This way + the loop becomes faster. */ + j = -s1_size; + + /* Offset the base pointers to compensate for the negative indices. */ + res_ptr -= j; + s1_ptr -= j; + + cy_limb = 0; + do + { + umul_ppmm (prod_high, prod_low, s1_ptr[j], s2_limb); + + prod_low += cy_limb; + cy_limb = (prod_low < cy_limb) + prod_high; + + x = res_ptr[j]; + prod_low = x + prod_low; + cy_limb += (prod_low < x); + res_ptr[j] = prod_low; + } + while (++j != 0); + + return cy_limb; +} |