1// SPDX-License-Identifier: GPL-2.0
2#include <linux/export.h>
3
4#include "libgcc.h"
5
6#define W_TYPE_SIZE 32
7
8#define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2))
9#define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1))
10#define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2))
11
12/* If we still don't have umul_ppmm, define it using plain C.  */
13#if !defined(umul_ppmm)
14#define umul_ppmm(w1, w0, u, v)						\
15	do {								\
16		unsigned long __x0, __x1, __x2, __x3;			\
17		unsigned short __ul, __vl, __uh, __vh;			\
18									\
19		__ul = __ll_lowpart(u);					\
20		__uh = __ll_highpart(u);				\
21		__vl = __ll_lowpart(v);					\
22		__vh = __ll_highpart(v);				\
23									\
24		__x0 = (unsigned long) __ul * __vl;			\
25		__x1 = (unsigned long) __ul * __vh;			\
26		__x2 = (unsigned long) __uh * __vl;			\
27		__x3 = (unsigned long) __uh * __vh;			\
28									\
29		__x1 += __ll_highpart(__x0); /* this can't give carry */\
30		__x1 += __x2; /* but this indeed can */			\
31		if (__x1 < __x2) /* did we get it? */			\
32		__x3 += __ll_B; /* yes, add it in the proper pos */	\
33									\
34		(w1) = __x3 + __ll_highpart(__x1);			\
35		(w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\
36	} while (0)
37#endif
38
39#if !defined(__umulsidi3)
40#define __umulsidi3(u, v) ({				\
41	DWunion __w;					\
42	umul_ppmm(__w.s.high, __w.s.low, u, v);		\
43	__w.ll;						\
44	})
45#endif
46
47long long __muldi3(long long u, long long v)
48{
49	const DWunion uu = {.ll = u};
50	const DWunion vv = {.ll = v};
51	DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)};
52
53	w.s.high += ((unsigned long) uu.s.low * (unsigned long) vv.s.high
54		+ (unsigned long) uu.s.high * (unsigned long) vv.s.low);
55
56	return w.ll;
57}
58EXPORT_SYMBOL(__muldi3);
59