38 lines
980 B
C
38 lines
980 B
C
/* Prototypes for condition spinning helper functions (part of libsys). */
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#ifndef _MINIX_SPIN_H
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#define _MINIX_SPIN_H
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/* Opaque spin state structure. */
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typedef struct {
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int s_state;
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u32_t s_usecs;
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u64_t s_base_tsc;
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clock_t s_base_uptime;
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int s_timeout;
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} spin_t;
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/* Functions. */
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void spin_init(spin_t *s, u32_t usecs);
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int spin_check(spin_t *s);
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/* Macros. */
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/* Execute a loop for at least 'u' microseconds, using spin object 's'.
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* The body of the loop is guaranteed to be executed at least once.
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*/
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#define SPIN_FOR(s,u) \
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for (spin_init((s), (u)); spin_check((s)); )
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/* Return whether spin object 's' timed out after a loop. */
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#define SPIN_TIMEOUT(s) ((s)->s_timeout)
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/* Spin until the given condition becomes true, or 'u' microseconds expired.
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* The condition is guaranteed to be checked at least once.
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*/
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#define SPIN_UNTIL(c,u) do { \
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spin_t s; \
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SPIN_FOR(&s,(u)) \
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if (c) break; \
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} while (0)
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#endif /* _MINIX_SPIN_H */
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