diff options
Diffstat (limited to 'lib/libpthread/arch')
-rw-r--r-- | lib/libpthread/arch/alpha/alpha/_atomic_lock.S | 45 | ||||
-rw-r--r-- | lib/libpthread/arch/i386/i386/_atomic_lock.S | 42 |
2 files changed, 87 insertions, 0 deletions
diff --git a/lib/libpthread/arch/alpha/alpha/_atomic_lock.S b/lib/libpthread/arch/alpha/alpha/_atomic_lock.S new file mode 100644 index 0000000..1cfb52f --- /dev/null +++ b/lib/libpthread/arch/alpha/alpha/_atomic_lock.S @@ -0,0 +1,45 @@ +/* + * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>. + * All rights reserved. + * copyright Douglas Santry 1996 + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the above copyright is retained + * in the source form. + * + * THIS SOFTWARE IS PROVIDED BY Douglas Santry AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL Douglas Santry OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + * + */ + +#include "SYS.h" + +/* + * Atomicly lock a location with an identifier provided the location + * is not currently locked. + * + * long _atomic_lock(long *); + * v0 will contain the return value (zero if lock obtained). + */ +LEAF(_atomic_lock,0) + LDGP(pv) + +0: ldq_l v0, 0(a0) /* read existing lock value */ + mov 1, t0 /* locked value to store */ + stq_c t0, 0(a0) /* attempt to store, status in t0 */ + beq t0, 1f /* branch foward to optimise prediction */ + mb /* sync with other processors */ + RET /* return with v0==0 if lock obtained */ +1: br 0b /* loop to try again */ +END(_atomic_lock) diff --git a/lib/libpthread/arch/i386/i386/_atomic_lock.S b/lib/libpthread/arch/i386/i386/_atomic_lock.S new file mode 100644 index 0000000..af49aff --- /dev/null +++ b/lib/libpthread/arch/i386/i386/_atomic_lock.S @@ -0,0 +1,42 @@ +/* + * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>. + * All rights reserved. + * copyright Douglas Santry 1996 + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the above copyright is retained + * in the source form. + * + * THIS SOFTWARE IS PROVIDED BY Douglas Santry AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL Douglas Santry OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_RCS) && !defined(lint) + .text + .asciz "$FreeBSD$" +#endif /* LIBC_RCS and not lint */ + +#include <machine/asm.h> + +/* + * Atomicly lock a location with an identifier provided the location + * is not currently locked. + * + * long _atomic_lock(long *); + * eax will contain the return value (zero if lock obtained). + */ +ENTRY(_atomic_lock) + movl 4(%esp), %ecx + movl $1, %eax + xchg %eax, (%ecx) + ret + |