cond_wait.h

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/* PROLOG END TAG zYx                                              */
#ifndef _PPU_COND_WAIT_H_
#define _PPU_COND_WAIT_H_

#include <ppu_intrinsics.h>
#include "sync_utils.h"
#include "mutex_lock.h"
#include "mutex_unlock.h"
#include "cond.h"

static __inline void _cond_wait (cond_ea_t cond, mutex_ea_t  mutex)
{
  int delta, cur_delta;
  unsigned int val, cond_val, signaled_cnt;
  void *p;


  SYNC_ULL_TO_PTR(cond, p);

  /* Atomically signal we have entered the condition wait by incrementing
   * the waiting count.
   */
  do {
    val = __lwarx(p);
    val = (val & ~0xFFFF) | ((val+1) & 0xFFFF);
  } while (__stwcx(p, val) == 0);


  /* Release the lock
   */
  _mutex_unlock (mutex);

  /* Determine the signal count needed for this 
   * participant to be signaled.
   */

  signaled_cnt = val >> 16;
  delta = (int)(val & 0xFFFF) - (int)signaled_cnt;
  if (delta < 0) delta = -delta;

  /* Wait until the signaled count reaches the count
   * previously determined.
   */
  do {
    cond_val = __lwarx(p);

    cur_delta = (int)(cond_val >> 16) - signaled_cnt;
    if (cur_delta < 0) cur_delta = -cur_delta;
   
  } while (cur_delta < delta);

  /* Relock the mutex 
   */
  _mutex_lock (mutex);
}

#endif /* _PPU_COND_WAIT_H_ */