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/* Copyright (C) 2005-2022 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU Offloading and Multi Processing Library
(libgomp).
Libgomp is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
Libgomp 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 General Public License for
more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
/* Provide target-specific access to the futex system call. */
#include <sys/syscall.h>
static inline long
sys_futex0 (int *addr, int op, int val)
{
register long int r0 __asm__ ("r0");
register long int r3 __asm__ ("r3");
register long int r4 __asm__ ("r4");
register long int r5 __asm__ ("r5");
register long int r6 __asm__ ("r6");
r0 = SYS_futex;
r3 = (long) addr;
r4 = op;
r5 = val;
r6 = 0;
/* ??? The powerpc64 sysdep.h file clobbers ctr; the powerpc32 sysdep.h
doesn't. It doesn't much matter for us. In the interest of unity,
go ahead and clobber it always. */
__asm volatile ("sc; mfcr %0"
: "=r"(r0), "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6)
: "r"(r0), "r"(r3), "r"(r4), "r"(r5), "r"(r6)
: "r7", "r8", "r9", "r10", "r11", "r12",
"cr0", "ctr", "memory");
if (__builtin_expect (r0 & (1 << 28), 0))
return r3;
return 0;
}
static inline void
futex_wait (int *addr, int val)
{
long err = sys_futex0 (addr, gomp_futex_wait, val);
if (__builtin_expect (err == ENOSYS, 0))
{
gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
sys_futex0 (addr, gomp_futex_wait, val);
}
}
static inline void
futex_wake (int *addr, int count)
{
long err = sys_futex0 (addr, gomp_futex_wake, count);
if (__builtin_expect (err == ENOSYS, 0))
{
gomp_futex_wait &= ~FUTEX_PRIVATE_FLAG;
gomp_futex_wake &= ~FUTEX_PRIVATE_FLAG;
sys_futex0 (addr, gomp_futex_wake, count);
}
}
static inline void
cpu_relax (void)
{
__asm volatile ("" : : : "memory");
}
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