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
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