| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/export.h> |
| |
| #include "libgcc.h" |
| |
| /* |
| * GCC 7 & older can suboptimally generate __multi3 calls for mips64r6, so for |
| * that specific case only we implement that intrinsic here. |
| * |
| * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981 |
| */ |
| #if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ < 8) |
| |
| /* 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 */ |