1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/export.h> |
3 | |
4 | #include "libgcc.h" |
5 | |
6 | /* |
7 | * GCC 7 & older can suboptimally generate __multi3 calls for mips64r6, so for |
8 | * that specific case only we implement that intrinsic 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__ < 8) |
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 | |