about summary refs log tree commit diff
path: root/sysdeps/sparc/cpu_relax.c
blob: 295d112a90916caf8da2e71ffa3587bb9a8cef63 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
/* CPU strand yielding for busy loops.  Linux/sparc version.
   Copyright (C) 2017-2020 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <sparc-ifunc.h>

#ifdef __sparc_v9__
static void
__cpu_relax_generic (void)
{
  asm volatile ("rd %ccr, %g0;"
		"rd %ccr, %g0;"
		"rd %ccr, %g0");
}

static void
__cpu_relax_pause (void)
{
  asm volatile ("wr %g0, 128, %asr27");
}

sparc_libc_ifunc (__cpu_relax,
		  hwcap & HWCAP_SPARC_PAUSE
		  ? __cpu_relax_pause
		  : __cpu_relax_generic)
#endif