| // 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 */ |