/*      $OpenBSD: atomic.h,v 1.5 2024/01/24 12:25:50 jca Exp $  */

/* Public Domain */

#ifndef _MACHINE_ATOMIC_H_
#define _MACHINE_ATOMIC_H_

#define __membar(_f) do {__asm volatile(_f ::: "memory"); } while (0)

#define membar_enter()          __membar("fence w,rw")
#define membar_exit()           __membar("fence rw,w")
#define membar_producer()       __membar("fence w,w")
#define membar_consumer()       __membar("fence r,r")
#define membar_sync()           __membar("fence rw,rw")

#if defined(_KERNEL)

/* virtio needs MP membars even on SP kernels */
#define virtio_membar_producer()        __membar("fence w,w")
#define virtio_membar_consumer()        __membar("fence r,r")
#define virtio_membar_sync()            __membar("fence rw,rw")

/*
 * Set bits
 * *p = *p | v
 */
static inline void
atomic_setbits_int(volatile unsigned int *p, unsigned int v)
{
        __asm volatile("amoor.w zero, %1, %0"
                        : "+A" (*p)
                        : "r" (v)
                        : "memory");
}

/*
 * Clear bits
 * *p = *p & (~v)
 */
static inline void
atomic_clearbits_int(volatile unsigned int *p, unsigned int v)
{
        __asm volatile("amoand.w zero, %1, %0"
                        : "+A" (*p)
                        : "r" (~v)
                        : "memory");
}

#endif /* defined(_KERNEL) */
#endif /* _MACHINE_ATOMIC_H_ */