mirror of https://gitee.com/openkylin/linux.git
55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
|
#include <linux/export.h>
|
||
|
|
|
||
|
|
#include "libgcc.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* GCC 7 suboptimally generates __multi3 calls for mips64r6, so for that
|
||
|
|
* specific case only we'll implement it here.
|
||
|
|
*
|
||
|
|
* See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981
|
||
|
|
*/
|
||
|
|
#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ == 7)
|
||
|
|
|
||
|
|
/* multiply 64-bit values, low 64-bits returned */
|
||
|
|
static inline long long notrace dmulu(long long a, long long b)
|
||
|
|
{
|
||
|
|
long long res;
|
||
|
|
|
||
|
|
asm ("dmulu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b));
|
||
|
|
return res;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* multiply 64-bit unsigned values, high 64-bits of 128-bit result returned */
|
||
|
|
static inline long long notrace dmuhu(long long a, long long b)
|
||
|
|
{
|
||
|
|
long long res;
|
||
|
|
|
||
|
|
asm ("dmuhu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b));
|
||
|
|
return res;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* multiply 128-bit values, low 128-bits returned */
|
||
|
|
ti_type notrace __multi3(ti_type a, ti_type b)
|
||
|
|
{
|
||
|
|
TWunion res, aa, bb;
|
||
|
|
|
||
|
|
aa.ti = a;
|
||
|
|
bb.ti = b;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* a * b = (a.lo * b.lo)
|
||
|
|
* + 2^64 * (a.hi * b.lo + a.lo * b.hi)
|
||
|
|
* [+ 2^128 * (a.hi * b.hi)]
|
||
|
|
*/
|
||
|
|
res.s.low = dmulu(aa.s.low, bb.s.low);
|
||
|
|
res.s.high = dmuhu(aa.s.low, bb.s.low);
|
||
|
|
res.s.high += dmulu(aa.s.high, bb.s.low);
|
||
|
|
res.s.high += dmulu(aa.s.low, bb.s.high);
|
||
|
|
|
||
|
|
return res.ti;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(__multi3);
|
||
|
|
|
||
|
|
#endif /* 64BIT && CPU_MIPSR6 && GCC7 */
|