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Add loadandclear(). It atomically loads a value from memory, clears the

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value in memory and returns the original value.
This commit is contained in:
bde 1995-05-11 07:24:35 +00:00
parent 8c986a8d8d
commit 539e9398fe
2 changed files with 24 additions and 2 deletions
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13
sys/amd64/include/cpufunc.h
View File

@ -30,7 +30,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: cpufunc.h,v 1.33 1995/02/16 13:21:47 bde Exp $
* $Id: cpufunc.h,v 1.34 1995/03/03 22:14:42 davidg Exp $
*/
/*
@ -189,6 +189,16 @@ inw(u_int port)
return (data);
}
static __inline unsigned
loadandclear(u_int *addr)
{
u_int result;
__asm __volatile("xorl %0,%0; xchgl %1,%0"
: "=r" (result) : "m" (*addr));
return (result);
}
static __inline void
outbv(u_int port, u_char data)
{
@ -319,6 +329,7 @@ void insb __P((u_int port, void *addr, size_t cnt));
void insl __P((u_int port, void *addr, size_t cnt));
void insw __P((u_int port, void *addr, size_t cnt));
u_short inw __P((u_int port));
u_int loadandclear __P((u_int *addr));
void outb __P((u_int port, u_char data));
void outl __P((u_int port, u_long data));
void outsb __P((u_int port, void *addr, size_t cnt));

13
sys/i386/include/cpufunc.h
View File

@ -30,7 +30,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: cpufunc.h,v 1.33 1995/02/16 13:21:47 bde Exp $
* $Id: cpufunc.h,v 1.34 1995/03/03 22:14:42 davidg Exp $
*/
/*
@ -189,6 +189,16 @@ inw(u_int port)
return (data);
}
static __inline unsigned
loadandclear(u_int *addr)
{
u_int result;
__asm __volatile("xorl %0,%0; xchgl %1,%0"
: "=r" (result) : "m" (*addr));
return (result);
}
static __inline void
outbv(u_int port, u_char data)
{
@ -319,6 +329,7 @@ void insb __P((u_int port, void *addr, size_t cnt));
void insl __P((u_int port, void *addr, size_t cnt));
void insw __P((u_int port, void *addr, size_t cnt));
u_short inw __P((u_int port));
u_int loadandclear __P((u_int *addr));
void outb __P((u_int port, u_char data));
void outl __P((u_int port, u_long data));
void outsb __P((u_int port, void *addr, size_t cnt));