61 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 */4 5#include <linux/export.h>6#include <linux/libgcc.h>7 8#define W_TYPE_SIZE 329 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#endif40 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#endif48 49long 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.high56 + (unsigned long) uu.s.high * (unsigned long) vv.s.low);57 58 return w.ll;59}60EXPORT_SYMBOL(__muldi3);61