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 | |