LCOM1920-T02G10

/* Prototypes for condition spinning helper functions (part of libsys). */

#ifndef _MINIX_SPIN_H

#define _MINIX_SPIN_H

/* Opaque spin state structure. */

typedef struct {

        int s_state;

        u32_t s_usecs;

        u64_t s_base_tsc;

        clock_t s_base_uptime;

        int s_timeout;

} spin_t;

/* Functions. */

void spin_init(spin_t *s, u32_t usecs);

int spin_check(spin_t *s);

/* Macros. */

/* Execute a loop for at least 'u' microseconds, using spin object 's'.

 * The body of the loop is guaranteed to be executed at least once.

 */

#define SPIN_FOR(s,u)                                                        \

        for (spin_init((s), (u)); spin_check((s)); )

/* Return whether spin object 's' timed out after a loop. */

#define SPIN_TIMEOUT(s) ((s)->s_timeout)

/* Spin until the given condition becomes true, or 'u' microseconds expired.

 * The condition is guaranteed to be checked at least once.

 */

#define SPIN_UNTIL(c,u) do {                                                \

        spin_t s;                                                        \

        SPIN_FOR(&s,(u))                                                \

                if (c) break;                                                \

} while (0)

#endif /* _MINIX_SPIN_H */