diff options
| author |   deraadt <deraadt@openbsd.org> | 2004-02-25 03:48:36 +0000 |
|---|---|---|
| committer | deraadt <deraadt@openbsd.org> | 2004-02-25 03:48:36 +0000 |
| commit | cad92e3743dcbcdacaafa22450ee31d5863dc4db (patch) | |
| tree | 7f53a2c61a8fd0c8963dea1127e60ff30bc90c42 /lib/libpthread/arch/amd64/_atomic_lock.c | |
| parent | typo in comment (diff) | |
| download | wireguard-openbsd-cad92e3743dcbcdacaafa22450ee31d5863dc4db.tar.xz wireguard-openbsd-cad92e3743dcbcdacaafa22450ee31d5863dc4db.zip | |
initial working pthreads support from sparc64, done with drahn. there are
some `debugging features' and other optimizations (such as not saving all
registers) that we can still do perhaps
Diffstat (limited to 'lib/libpthread/arch/amd64/_atomic_lock.c')
| -rw-r--r-- | lib/libpthread/arch/amd64/_atomic_lock.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/lib/libpthread/arch/amd64/_atomic_lock.c b/lib/libpthread/arch/amd64/_atomic_lock.c index 087186e2858..70bdb487381 100644 --- a/lib/libpthread/arch/amd64/_atomic_lock.c +++ b/lib/libpthread/arch/amd64/_atomic_lock.c @@ -1,5 +1,6 @@ +/* $OpenBSD: _atomic_lock.c,v 1.2 2004/02/25 03:48:36 deraadt Exp $ */ /* - * Atomic lock for amd64 + * Atomic lock for amd64 -- taken from i386 code. */ #include "spinlock.h" @@ -7,5 +8,16 @@ int _atomic_lock(volatile _spinlock_lock_t *lock) { - /* dummy for now */ + _spinlock_lock_t old; + + /* + * Use the eXCHanGe instruction to swap the lock value with + * a local variable containing the locked state. + */ + old = _SPINLOCK_LOCKED; + __asm__("xchg %0,%1" + : "=r" (old), "=m" (*lock) + : "0" (old), "1" (*lock)); + + return (old != _SPINLOCK_UNLOCKED); } |