1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 */ 4 5 #include <linux/export.h> 6 #include <linux/libgcc.h> 7 8 #define W_TYPE_SIZE 32 9 10 #define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2)) 11 #define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1)) 12 #define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2)) 13 14 /* If we still don't have umul_ppmm, define it using plain C. */ 15 #if !defined(umul_ppmm) 16 #define umul_ppmm(w1, w0, u, v) \ 17 do { \ 18 unsigned long __x0, __x1, __x2, __x3; \ 19 unsigned short __ul, __vl, __uh, __vh; \ 20 \ 21 __ul = __ll_lowpart(u); \ 22 __uh = __ll_highpart(u); \ 23 __vl = __ll_lowpart(v); \ 24 __vh = __ll_highpart(v); \ 25 \ 26 __x0 = (unsigned long) __ul * __vl; \ 27 __x1 = (unsigned long) __ul * __vh; \ 28 __x2 = (unsigned long) __uh * __vl; \ 29 __x3 = (unsigned long) __uh * __vh; \ 30 \ 31 __x1 += __ll_highpart(__x0); /* this can't give carry */\ 32 __x1 += __x2; /* but this indeed can */ \ 33 if (__x1 < __x2) /* did we get it? */ \ 34 __x3 += __ll_B; /* yes, add it in the proper pos */ \ 35 \ 36 (w1) = __x3 + __ll_highpart(__x1); \ 37 (w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\ 38 } while (0) 39 #endif 40 41 #if !defined(__umulsidi3) 42 #define __umulsidi3(u, v) ({ \ 43 DWunion __w; \ 44 umul_ppmm(__w.s.high, __w.s.low, u, v); \ 45 __w.ll; \ 46 }) 47 #endif 48 49 long long notrace __muldi3(long long u, long long v) 50 { 51 const DWunion uu = {.ll = u}; 52 const DWunion vv = {.ll = v}; 53 DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)}; 54 55 w.s.high += ((unsigned long) uu.s.low * (unsigned long) vv.s.high 56 + (unsigned long) uu.s.high * (unsigned long) vv.s.low); 57 58 return w.ll; 59 } 60 EXPORT_SYMBOL(__muldi3); 61