1 /* CPU strand yielding for busy loops. Linux/sparc version.
2 Copyright (C) 2017-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <sparc-ifunc.h>
20
21 #ifdef __sparc_v9__
22 static void
__cpu_relax_generic(void)23 __cpu_relax_generic (void)
24 {
25 asm volatile ("rd %ccr, %g0;"
26 "rd %ccr, %g0;"
27 "rd %ccr, %g0");
28 }
29
30 static void
__cpu_relax_pause(void)31 __cpu_relax_pause (void)
32 {
33 asm volatile ("wr %g0, 128, %asr27");
34 }
35
36 sparc_libc_ifunc (__cpu_relax,
37 hwcap & HWCAP_SPARC_PAUSE
38 ? __cpu_relax_pause
39 : __cpu_relax_generic)
40 #endif
41