diff options
Diffstat (limited to 'lib/libpthread/arch/m68k/_atomic_lock.c')
| -rw-r--r-- | lib/libpthread/arch/m68k/_atomic_lock.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/lib/libpthread/arch/m68k/_atomic_lock.c b/lib/libpthread/arch/m68k/_atomic_lock.c index 329fdb5ca37..c91b11ce26e 100644 --- a/lib/libpthread/arch/m68k/_atomic_lock.c +++ b/lib/libpthread/arch/m68k/_atomic_lock.c @@ -1,4 +1,4 @@ -/* $OpenBSD: _atomic_lock.c,v 1.4 1998/12/21 13:03:44 d Exp $ */ +/* $OpenBSD: _atomic_lock.c,v 1.5 1999/03/10 09:32:01 d Exp $ */ /* * Atomic lock for m68k */ @@ -20,10 +20,18 @@ _atomic_lock(volatile _spinlock_lock_t *lock) * old = 0; * CAS(old, 1, *lock); * if (old == 1) { lock was acquired } + * + * From the MC68030 User's Manual (Motorola), page `3-13': + * CAS Dc,Du,<ea>: + * (<ea> - Dc) -> cc; + * if Z then Du -> <ea> + * else <ea> -> Dc; */ old = _SPINLOCK_UNLOCKED; - __asm__("casl %0, %2, %1" : "=d"(old), "=m"(*lock) - : "d"(_SPINLOCK_LOCKED), "0"(old)); + __asm__("casl %0, %2, %1" : "=d" (old), "=m" (*lock) + : "d" (_SPINLOCK_LOCKED), + "0" (old), "1" (*lock) + : "cc"); return (old != _SPINLOCK_UNLOCKED); } |