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#define READERS     50
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#define READERS     50
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#define WRITERS     50
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#define WRITERS     50
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static rwlock_t rwlock;
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static rwlock_t rwlock;
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static SPINLOCK_INITIALIZE(lock);
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SPINLOCK_INITIALIZE(rw_lock);
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static waitq_t can_start;
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static waitq_t can_start;
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static uint32_t seed = 0xdeadbeef;
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static uint32_t seed = 0xdeadbeef;
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static uint32_t random(uint32_t max)
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static uint32_t random(uint32_t max)
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{
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{
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    uint32_t rc;
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    uint32_t rc;
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    spinlock_lock(&lock);  
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    spinlock_lock(&rw_lock);   
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    rc = seed % max;
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    rc = seed % max;
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    seed = (((seed<<2) ^ (seed>>2)) * 487) + rc;
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    seed = (((seed<<2) ^ (seed>>2)) * 487) + rc;
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    spinlock_unlock(&lock);
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    spinlock_unlock(&rw_lock);
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    return rc;
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    return rc;
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}
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}
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static void writer(void *arg)
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static void writer(void *arg)