Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[platform/kernel/linux-starfive.git] / lib / muldi3.c
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);