1/* mpn_redc_2. Set rp[] <- up[]/R^n mod mp[]. Clobber up[]. 2 mp[] is n limbs; up[] is 2n limbs. 3 4 THIS IS AN INTERNAL FUNCTION WITH A MUTABLE INTERFACE. IT IS ONLY 5 SAFE TO REACH THIS FUNCTION THROUGH DOCUMENTED INTERFACES. 6 7Copyright (C) 2000-2002, 2004, 2008, 2012 Free Software Foundation, Inc. 8 9This file is part of the GNU MP Library. 10 11The GNU MP Library is free software; you can redistribute it and/or modify 12it under the terms of either: 13 14 * the GNU Lesser General Public License as published by the Free 15 Software Foundation; either version 3 of the License, or (at your 16 option) any later version. 17 18or 19 20 * the GNU General Public License as published by the Free Software 21 Foundation; either version 2 of the License, or (at your option) any 22 later version. 23 24or both in parallel, as here. 25 26The GNU MP Library is distributed in the hope that it will be useful, but 27WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 28or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 29for more details. 30 31You should have received copies of the GNU General Public License and the 32GNU Lesser General Public License along with the GNU MP Library. If not, 33see https://www.gnu.org/licenses/. */ 34 35#include "gmp-impl.h" 36#include "longlong.h" 37 38 39#if GMP_NAIL_BITS != 0 40you lose 41#endif 42 43/* For testing purposes, define our own mpn_addmul_2 if there is none already 44 available. */ 45#ifndef HAVE_NATIVE_mpn_addmul_2 46#undef mpn_addmul_2 47static mp_limb_t 48mpn_addmul_2 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_srcptr vp) 49{ 50 rp[n] = mpn_addmul_1 (rp, up, n, vp[0]); 51 return mpn_addmul_1 (rp + 1, up, n, vp[1]); 52} 53#endif 54 55#if defined (__GNUC__) && ! defined (NO_ASM) \ 56 && defined (__ia64) && W_TYPE_SIZE == 64 57#define umul2low(ph, pl, uh, ul, vh, vl) \ 58 do { \ 59 mp_limb_t _ph, _pl; \ 60 __asm__ ("xma.hu %0 = %3, %5, f0\n\t" \ 61 "xma.l %1 = %3, %5, f0\n\t" \ 62 ";;\n\t" \ 63 "xma.l %0 = %3, %4, %0\n\t" \ 64 ";;\n\t" \ 65 "xma.l %0 = %2, %5, %0" \ 66 : "=&f" (ph), "=&f" (pl) \ 67 : "f" (uh), "f" (ul), "f" (vh), "f" (vl)); \ 68 } while (0) 69#endif 70 71#ifndef umul2low 72#define umul2low(ph, pl, uh, ul, vh, vl) \ 73 do { \ 74 mp_limb_t _ph, _pl; \ 75 umul_ppmm (_ph, _pl, ul, vl); \ 76 (ph) = _ph + (ul) * (vh) + (uh) * (vl); \ 77 (pl) = _pl; \ 78 } while (0) 79#endif 80 81mp_limb_t 82mpn_redc_2 (mp_ptr rp, mp_ptr up, mp_srcptr mp, mp_size_t n, mp_srcptr mip) 83{ 84 mp_limb_t q[2]; 85 mp_size_t j; 86 mp_limb_t upn; 87 mp_limb_t cy; 88 89 ASSERT (n > 0); 90 ASSERT_MPN (up, 2*n); 91 92 if ((n & 1) != 0) 93 { 94 up[0] = mpn_addmul_1 (up, mp, n, (up[0] * mip[0]) & GMP_NUMB_MASK); 95 up++; 96 } 97 98 for (j = n - 2; j >= 0; j -= 2) 99 { 100 umul2low (q[1], q[0], mip[1], mip[0], up[1], up[0]); 101 upn = up[n]; /* mpn_addmul_2 overwrites this */ 102 up[1] = mpn_addmul_2 (up, mp, n, q); 103 up[0] = up[n]; 104 up[n] = upn; 105 up += 2; 106 } 107 108 cy = mpn_add_n (rp, up, up - n, n); 109 return cy; 110} 111