predictorhash2.h

   1 /*****************************************************/
   2 /***** Same as predictorhash.h, but table is param ***/
   3 /***** etrizable here                              ***/
   4 /*****************************************************/
   5
   6
   7 #ifndef PREDICTORHASH_H
   8 #define PREDICTORHASH_H
   9
  10
  11
  12 #define PREDICT_TABLE_SIZE 0x1000 // 256 entry table
  13 #define INDEX_MASK 0x00000FFF // 8 bit index in a 256 entry table
  14 #define TAG_MASK   0x00003000 // next 6 bits for tag
  15 #define TAG_SHIFT  12         // shift to bring the tag down for comparison.
  16 #define HASH_SHIFT 5 // shift the prev_hash by this many bits before ORing with last_hash
  17
  18 struct predict_table_entry{
  19 /*Phase prediction paper says that their predictor has
  20 256 entries encompassing less than 500 bytes. This should make each entry of
  21 2 bytes (a little less).  How to divide this between tag and predicted id ?
  22
  23 On-line simpoint says that they have a signature table of 1024 entries. Thus
  24 the phase_id can go up to 10 bits. This leaves only 6 bits for Tag ?  Or did
  25 they use larger table entries ?
  26 */
  27
  28         // limit the size in the light of above discussion?
  29         unsigned int *tag;
  30         unsigned int *phase_id;
  31 };
  32
  33 struct PredictorHash {
  34
  35 // how much in future we have to predict
  36         unsigned int pred_future_len;
  37         unsigned int kept_futur_len;
  38         unsigned int kept_tag_len_bits; // in bits
  39         unsigned int kept_tag_var_len;  // var len. 1 ftm
  40         unsigned int table_size;    // in powers of two
  41
  42         // based on table size
  43         unsigned int index_mask;
  44         unsigned int tag_mask;
  45         unsigned int tag_shift;
  46
  47
  48         unsigned short * history;
  49         unsigned int hist_head;
  50         unsigned int hist_tail;
  51
  52         unsigned int *temp_kept_futur;
  53         /*it shows only the num-entries. size of history = hist_len*2*2 bytes
  54          * if short */
  55         unsigned int history_length;
  56         int largest_center;
  57
  58
  59         // prediction table
  60         // see the size : shall we limit the size ??
  61         struct predict_table_entry *predict_table;
  62         unsigned int prev_hash;       // contains the id and num_occr of
  63                                       // prev (before the last) phase hashed
  64
  65         unsigned int last_phase_predictions; //stats
  66         unsigned int new_phase_predictions;
  67
  68 };
  69
  70 struct PredictorHash * predictor_create(
  71                   unsigned int hist_size
  72                   ,unsigned int pred_futur_len
  73                   ,unsigned int kept_futur_len
  74                   ,unsigned int kept_tag_len
  75                   ,unsigned int table_size
  76                 );
  77
  78 unsigned int calc_index_mask( unsigned int table_size);
  79 unsigned int calc_tag_mask( unsigned int table_size);
  80 unsigned int calc_tag_shift( unsigned int table_size);
  81
  82 unsigned int compare_two_arrays( unsigned int *a1, unsigned int *a2
  83                                  , int len, float success_measure );
  84 #endif //PREDICTORHASH_H