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
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.high
56		+ (unsigned long) uu.s.high * (unsigned long) vv.s.low);
57
58	return w.ll;
59}
60EXPORT_SYMBOL(__muldi3);
61