1 /* Cray PVP/IEEE mpn_addmul_1 -- multiply a limb vector with a limb and add the 2 result to a second limb vector. 3 4 Copyright 2000-2002 Free Software Foundation, Inc. 5 6 This file is part of the GNU MP Library. 7 8 The GNU MP Library is free software; you can redistribute it and/or modify 9 it under the terms of either: 10 11 * the GNU Lesser General Public License as published by the Free 12 Software Foundation; either version 3 of the License, or (at your 13 option) any later version. 14 15 or 16 17 * the GNU General Public License as published by the Free Software 18 Foundation; either version 2 of the License, or (at your option) any 19 later version. 20 21 or both in parallel, as here. 22 23 The GNU MP Library is distributed in the hope that it will be useful, but 24 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 25 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 26 for more details. 27 28 You should have received copies of the GNU General Public License and the 29 GNU Lesser General Public License along with the GNU MP Library. If not, 30 see https://www.gnu.org/licenses/. */ 31 32 /* This code runs at just under 9 cycles/limb on a T90. That is not perfect, 33 mainly due to vector register shortage in the main loop. Assembly code 34 should bring it down to perhaps 7 cycles/limb. */ 35 36 #include <intrinsics.h> 37 #include "gmp-impl.h" 38 39 mp_limb_t 40 mpn_addmul_1 (mp_ptr rp, mp_srcptr up, mp_size_t n, mp_limb_t vl) 41 { 42 mp_limb_t cy[n]; 43 mp_limb_t a, b, r, s0, s1, c0, c1; 44 mp_size_t i; 45 int more_carries; 46 47 if (up == rp) 48 { 49 /* The algorithm used below cannot handle overlap. Handle it here by 50 making a temporary copy of the source vector, then call ourselves. */ 51 mp_limb_t xp[n]; 52 MPN_COPY (xp, up, n); 53 return mpn_addmul_1 (rp, xp, n, vl); 54 } 55 56 a = up[0] * vl; 57 r = rp[0]; 58 s0 = a + r; 59 rp[0] = s0; 60 c0 = ((a & r) | ((a | r) & ~s0)) >> 63; 61 cy[0] = c0; 62 63 /* Main multiply loop. Generate a raw accumulated output product in rp[] 64 and a carry vector in cy[]. */ 65 #pragma _CRI ivdep 66 for (i = 1; i < n; i++) 67 { 68 a = up[i] * vl; 69 b = _int_mult_upper (up[i - 1], vl); 70 s0 = a + b; 71 c0 = ((a & b) | ((a | b) & ~s0)) >> 63; 72 r = rp[i]; 73 s1 = s0 + r; 74 rp[i] = s1; 75 c1 = ((s0 & r) | ((s0 | r) & ~s1)) >> 63; 76 cy[i] = c0 + c1; 77 } 78 /* Carry add loop. Add the carry vector cy[] to the raw result rp[] and 79 store the new result back to rp[]. */ 80 more_carries = 0; 81 #pragma _CRI ivdep 82 for (i = 1; i < n; i++) 83 { 84 r = rp[i]; 85 c0 = cy[i - 1]; 86 s0 = r + c0; 87 rp[i] = s0; 88 c0 = (r & ~s0) >> 63; 89 more_carries += c0; 90 } 91 /* If that second loop generated carry, handle that in scalar loop. */ 92 if (more_carries) 93 { 94 mp_limb_t cyrec = 0; 95 /* Look for places where rp[k] == 0 and cy[k-1] == 1 or 96 rp[k] == 1 and cy[k-1] == 2. 97 These are where we got a recurrency carry. */ 98 for (i = 1; i < n; i++) 99 { 100 r = rp[i]; 101 c0 = r < cy[i - 1]; 102 s0 = r + cyrec; 103 rp[i] = s0; 104 c1 = (r & ~s0) >> 63; 105 cyrec = c0 | c1; 106 } 107 return _int_mult_upper (up[n - 1], vl) + cyrec + cy[n - 1]; 108 } 109 110 return _int_mult_upper (up[n - 1], vl) + cy[n - 1]; 111 } 112