1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License as published by 4 * the Free Software Foundation; either version 2 of the License, or 5 * (at your option) any later version. 6 * 7 * This program is distributed in the hope that it will be useful, 8 * but WITHOUT ANY WARRANTY; without even the implied warranty of 9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 10 * GNU General Public License for more details. 11 * 12 * You should have received a copy of the GNU General Public License 13 * along with this program; if not, see the file COPYING, or write 14 * to the Free Software Foundation, Inc. 15 */ 16 17 #include <linux/export.h> 18 #include <linux/libgcc.h> 19 20 #define W_TYPE_SIZE 32 21 22 #define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2)) 23 #define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1)) 24 #define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2)) 25 26 /* If we still don't have umul_ppmm, define it using plain C. */ 27 #if !defined(umul_ppmm) 28 #define umul_ppmm(w1, w0, u, v) \ 29 do { \ 30 unsigned long __x0, __x1, __x2, __x3; \ 31 unsigned short __ul, __vl, __uh, __vh; \ 32 \ 33 __ul = __ll_lowpart(u); \ 34 __uh = __ll_highpart(u); \ 35 __vl = __ll_lowpart(v); \ 36 __vh = __ll_highpart(v); \ 37 \ 38 __x0 = (unsigned long) __ul * __vl; \ 39 __x1 = (unsigned long) __ul * __vh; \ 40 __x2 = (unsigned long) __uh * __vl; \ 41 __x3 = (unsigned long) __uh * __vh; \ 42 \ 43 __x1 += __ll_highpart(__x0); /* this can't give carry */\ 44 __x1 += __x2; /* but this indeed can */ \ 45 if (__x1 < __x2) /* did we get it? */ \ 46 __x3 += __ll_B; /* yes, add it in the proper pos */ \ 47 \ 48 (w1) = __x3 + __ll_highpart(__x1); \ 49 (w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\ 50 } while (0) 51 #endif 52 53 #if !defined(__umulsidi3) 54 #define __umulsidi3(u, v) ({ \ 55 DWunion __w; \ 56 umul_ppmm(__w.s.high, __w.s.low, u, v); \ 57 __w.ll; \ 58 }) 59 #endif 60 61 long long notrace __muldi3(long long u, long long v) 62 { 63 const DWunion uu = {.ll = u}; 64 const DWunion vv = {.ll = v}; 65 DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)}; 66 67 w.s.high += ((unsigned long) uu.s.low * (unsigned long) vv.s.high 68 + (unsigned long) uu.s.high * (unsigned long) vv.s.low); 69 70 return w.ll; 71 } 72 EXPORT_SYMBOL(__muldi3); 73