Release 4.17 lib/muldi3.c
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.
*/
#include <linux/export.h>
#include <linux/libgcc.h>
#define W_TYPE_SIZE 32
#define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2))
#define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1))
#define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2))
/* If we still don't have umul_ppmm, define it using plain C. */
#if !defined(umul_ppmm)
#define umul_ppmm(w1, w0, u, v) \
do { \
unsigned long __x0, __x1, __x2, __x3; \
unsigned short __ul, __vl, __uh, __vh; \
\
__ul = __ll_lowpart(u); \
__uh = __ll_highpart(u); \
__vl = __ll_lowpart(v); \
__vh = __ll_highpart(v); \
\
__x0 = (unsigned long) __ul * __vl; \
__x1 = (unsigned long) __ul * __vh; \
__x2 = (unsigned long) __uh * __vl; \
__x3 = (unsigned long) __uh * __vh; \
\
__x1 += __ll_highpart(__x0); /* this can't give carry */\
__x1 += __x2; /* but this indeed can */ \
if (__x1 < __x2) /* did we get it? */ \
__x3 += __ll_B; /* yes, add it in the proper pos */ \
\
(w1) = __x3 + __ll_highpart(__x1); \
(w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\
} while (0)
#endif
#if !defined(__umulsidi3)
#define __umulsidi3(u, v) ({ \
DWunion __w; \
umul_ppmm(__w.s.high, __w.s.low, u, v); \
__w.ll; \
})
#endif
long long notrace __muldi3(long long u, long long v)
{
const DWunion uu = {.ll = u};
const DWunion vv = {.ll = v};
DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)};
w.s.high += ((unsigned long) uu.s.low * (unsigned long) vv.s.high
+ (unsigned long) uu.s.high * (unsigned long) vv.s.low);
return w.ll;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Palmer Dabbelt | 105 | 100.00% | 1 | 100.00% |
| Total | 105 | 100.00% | 1 | 100.00% |
EXPORT_SYMBOL(__muldi3);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Palmer Dabbelt | 188 | 99.47% | 1 | 50.00% |
| Christoph Hellwig | 1 | 0.53% | 1 | 50.00% |
| Total | 189 | 100.00% | 2 | 100.00% |
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