1 /* 2 * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org> 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining 5 * a copy of this software and associated documentation files (the 6 * "Software"), to deal in the Software without restriction, including 7 * without limitation the rights to use, copy, modify, merge, publish, 8 * distribute, sublicense, and/or sell copies of the Software, and to 9 * permit persons to whom the Software is furnished to do so, subject to 10 * the following conditions: 11 * 12 * The above copyright notice and this permission notice shall be 13 * included in all copies or substantial portions of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 * SOFTWARE. 23 */ 24 25 #include "inner.h" 26 27 /* see inner.h */ 28 void 29 br_i15_mulacc(uint16_t *d, const uint16_t *a, const uint16_t *b) 30 { 31 size_t alen, blen, u; 32 unsigned dl, dh; 33 34 alen = (a[0] + 15) >> 4; 35 blen = (b[0] + 15) >> 4; 36 37 /* 38 * Announced bit length of d[] will be the sum of the announced 39 * bit lengths of a[] and b[]; but the lengths are encoded. 40 */ 41 dl = (a[0] & 15) + (b[0] & 15); 42 dh = (a[0] >> 4) + (b[0] >> 4); 43 d[0] = (dh << 4) + dl + (~(uint32_t)(dl - 15) >> 31); 44 45 for (u = 0; u < blen; u ++) { 46 uint32_t f; 47 size_t v; 48 uint32_t cc; 49 50 f = b[1 + u]; 51 cc = 0; 52 for (v = 0; v < alen; v ++) { 53 uint32_t z; 54 55 z = (uint32_t)d[1 + u + v] + MUL15(f, a[1 + v]) + cc; 56 cc = z >> 15; 57 d[1 + u + v] = z & 0x7FFF; 58 } 59 d[1 + u + alen] = cc; 60 } 61 } 62