1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/export.h> 3 4 #include "libgcc.h" 5 6 /* 7 * GCC 7 suboptimally generates __multi3 calls for mips64r6, so for that 8 * specific case only we'll implement it here. 9 * 10 * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981 11 */ 12 #if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ == 7) 13 14 /* multiply 64-bit values, low 64-bits returned */ 15 static inline long long notrace dmulu(long long a, long long b) 16 { 17 long long res; 18 19 asm ("dmulu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b)); 20 return res; 21 } 22 23 /* multiply 64-bit unsigned values, high 64-bits of 128-bit result returned */ 24 static inline long long notrace dmuhu(long long a, long long b) 25 { 26 long long res; 27 28 asm ("dmuhu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b)); 29 return res; 30 } 31 32 /* multiply 128-bit values, low 128-bits returned */ 33 ti_type notrace __multi3(ti_type a, ti_type b) 34 { 35 TWunion res, aa, bb; 36 37 aa.ti = a; 38 bb.ti = b; 39 40 /* 41 * a * b = (a.lo * b.lo) 42 * + 2^64 * (a.hi * b.lo + a.lo * b.hi) 43 * [+ 2^128 * (a.hi * b.hi)] 44 */ 45 res.s.low = dmulu(aa.s.low, bb.s.low); 46 res.s.high = dmuhu(aa.s.low, bb.s.low); 47 res.s.high += dmulu(aa.s.high, bb.s.low); 48 res.s.high += dmulu(aa.s.low, bb.s.high); 49 50 return res.ti; 51 } 52 EXPORT_SYMBOL(__multi3); 53 54 #endif /* 64BIT && CPU_MIPSR6 && GCC7 */ 55