pd.if.org Git - liblfds/blob - liblfds/liblfds7.0.0/liblfds700/src/lfds700_freelist/lfds700_freelist_pop.c

   1 /***** includes *****/
   2 #include "lfds700_freelist_internal.h"
   3
   4
   5
   6
   7
   8 /****************************************************************************/
   9 int lfds700_freelist_pop( struct lfds700_freelist_state *fs, struct lfds700_freelist_element **fe, struct lfds700_misc_prng_state *ps )
  10 {
  11   char unsigned
  12     result;
  13
  14   lfds700_pal_uint_t
  15     backoff_iteration = LFDS700_MISC_ABSTRACTION_BACKOFF_INITIAL_VALUE;
  16
  17   struct lfds700_freelist_element LFDS700_PAL_ALIGN(LFDS700_PAL_ALIGN_DOUBLE_POINTER)
  18     *new_top[PAC_SIZE],
  19     *volatile original_top[PAC_SIZE];
  20
  21   LFDS700_PAL_ASSERT( fs != NULL );
  22   LFDS700_PAL_ASSERT( fe != NULL );
  23   LFDS700_PAL_ASSERT( ps != NULL );
  24
  25   LFDS700_PAL_BARRIER_PROCESSOR_LOAD;
  26
  27   original_top[COUNTER] = fs->top[COUNTER];
  28   original_top[POINTER] = fs->top[POINTER];
  29
  30   do
  31   {
  32     if( original_top[POINTER] == NULL )
  33     {
  34       *fe = NULL;
  35       return( 0 );
  36     }
  37
  38     new_top[COUNTER] = original_top[COUNTER] + 1;
  39     new_top[POINTER] = original_top[POINTER]->next;
  40
  41     LFDS700_PAL_ATOMIC_DWCAS_WITH_BACKOFF( &fs->top, original_top, new_top, LFDS700_MISC_CAS_STRENGTH_WEAK, result, backoff_iteration, ps );
  42
  43     if( result != 1 )
  44       LFDS700_PAL_BARRIER_PROCESSOR_LOAD;
  45   }
  46   while( result != 1 );
  47
  48   *fe = original_top[POINTER];
  49
  50   return( 1 );
  51 }
  52