| /* mpn_submul_1 -- multiply the N long limb vector pointed to by UP by VL, |
| subtract the N least significant limbs of the product from the limb |
| vector pointed to by RP. Return the most significant limb of the |
| product, adjusted for carry-out from the subtraction. |
| |
| Copyright 1992, 1993, 1994, 1996, 2000, 2002, 2004 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" |
| #include "longlong.h" |
| |
| |
| #if GMP_NAIL_BITS == 0 |
| |
| mp_limb_t |
| mpn_submul_1 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_limb_t vl) |
| { |
| mp_limb_t ul, cl, hpl, lpl, rl; |
| |
| ASSERT (n >= 1); |
| ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); |
| |
| cl = 0; |
| do |
| { |
| ul = *up++; |
| umul_ppmm (hpl, lpl, ul, vl); |
| |
| lpl += cl; |
| cl = (lpl < cl) + hpl; |
| |
| rl = *rp; |
| lpl = rl - lpl; |
| cl += lpl > rl; |
| *rp++ = lpl; |
| } |
| while (--n != 0); |
| |
| return cl; |
| } |
| |
| #endif |
| |
| #if GMP_NAIL_BITS == 1 |
| |
| mp_limb_t |
| mpn_submul_1 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_limb_t vl) |
| { |
| mp_limb_t shifted_vl, ul, rl, lpl, hpl, prev_hpl, cl, xl, c1, c2, c3; |
| |
| ASSERT (n >= 1); |
| ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); |
| ASSERT_MPN (rp, n); |
| ASSERT_MPN (up, n); |
| ASSERT_LIMB (vl); |
| |
| shifted_vl = vl << GMP_NAIL_BITS; |
| cl = 0; |
| prev_hpl = 0; |
| do |
| { |
| ul = *up++; |
| rl = *rp; |
| umul_ppmm (hpl, lpl, ul, shifted_vl); |
| lpl >>= GMP_NAIL_BITS; |
| SUBC_LIMB (c1, xl, rl, prev_hpl); |
| SUBC_LIMB (c2, xl, xl, lpl); |
| SUBC_LIMB (c3, xl, xl, cl); |
| cl = c1 + c2 + c3; |
| *rp++ = xl; |
| prev_hpl = hpl; |
| } |
| while (--n != 0); |
| |
| return prev_hpl + cl; |
| } |
| |
| #endif |
| |
| #if GMP_NAIL_BITS >= 2 |
| |
| mp_limb_t |
| mpn_submul_1 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_limb_t vl) |
| { |
| mp_limb_t shifted_vl, ul, rl, lpl, hpl, prev_hpl, xw, cl, xl; |
| |
| ASSERT (n >= 1); |
| ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n)); |
| ASSERT_MPN (rp, n); |
| ASSERT_MPN (up, n); |
| ASSERT_LIMB (vl); |
| |
| shifted_vl = vl << GMP_NAIL_BITS; |
| cl = 0; |
| prev_hpl = 0; |
| do |
| { |
| ul = *up++; |
| rl = *rp; |
| umul_ppmm (hpl, lpl, ul, shifted_vl); |
| lpl >>= GMP_NAIL_BITS; |
| xw = rl - (prev_hpl + lpl) + cl; |
| cl = (mp_limb_signed_t) xw >> GMP_NUMB_BITS; /* FIXME: non-portable */ |
| xl = xw & GMP_NUMB_MASK; |
| *rp++ = xl; |
| prev_hpl = hpl; |
| } |
| while (--n != 0); |
| |
| return prev_hpl - cl; |
| } |
| |
| #endif |