mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-13 03:29:50 +00:00
77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
/* Copyright (C) 2008-2017 Free Software Foundation, Inc.
|
|
Contributed by Jakub Jelinek <jakub@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/>. */
|
|
|
|
/* This is a Linux specific implementation of a mutex synchronization
|
|
mechanism for libgomp. This type is private to the library. This
|
|
implementation uses atomic instructions and the futex syscall.
|
|
|
|
A ptrlock has four states:
|
|
0/NULL Initial
|
|
1 Owned by me, I get to write a pointer to ptrlock.
|
|
2 Some thread is waiting on the ptrlock.
|
|
>2 Ptrlock contains a valid pointer.
|
|
It is not valid to gain the ptrlock and then write a NULL to it. */
|
|
|
|
#ifndef GOMP_PTRLOCK_H
|
|
#define GOMP_PTRLOCK_H 1
|
|
|
|
typedef void *gomp_ptrlock_t;
|
|
|
|
static inline void gomp_ptrlock_init (gomp_ptrlock_t *ptrlock, void *ptr)
|
|
{
|
|
*ptrlock = ptr;
|
|
}
|
|
|
|
extern void *gomp_ptrlock_get_slow (gomp_ptrlock_t *ptrlock);
|
|
static inline void *gomp_ptrlock_get (gomp_ptrlock_t *ptrlock)
|
|
{
|
|
uintptr_t oldval;
|
|
|
|
uintptr_t v = (uintptr_t) __atomic_load_n (ptrlock, MEMMODEL_ACQUIRE);
|
|
if (v > 2)
|
|
return (void *) v;
|
|
|
|
oldval = 0;
|
|
if (__atomic_compare_exchange_n (ptrlock, &oldval, 1, false,
|
|
MEMMODEL_ACQUIRE, MEMMODEL_ACQUIRE))
|
|
return NULL;
|
|
|
|
return gomp_ptrlock_get_slow (ptrlock);
|
|
}
|
|
|
|
extern void gomp_ptrlock_set_slow (gomp_ptrlock_t *ptrlock);
|
|
static inline void gomp_ptrlock_set (gomp_ptrlock_t *ptrlock, void *ptr)
|
|
{
|
|
void *wait = __atomic_exchange_n (ptrlock, ptr, MEMMODEL_RELEASE);
|
|
if ((uintptr_t) wait != 1)
|
|
gomp_ptrlock_set_slow (ptrlock);
|
|
}
|
|
|
|
static inline void gomp_ptrlock_destroy (gomp_ptrlock_t *ptrlock)
|
|
{
|
|
}
|
|
|
|
#endif /* GOMP_PTRLOCK_H */
|