csci3753

CSCI3753 Coursework
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pager-predict.c (3431B)

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// Jack Sangdahl
// CSCI3753 SP24
// PA8 Predict
#include "../common/simulator.h"
#include <stdbool.h>
#include <string.h>

static const float transition[MAXPROCESSES][MAXPROCPAGES] = {
    {0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0.93, 0, 0, 0, 0, 0, 0.07, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0.15, 0, 0, 0, 0, 0, 0.85, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    {0.04, 0, 0, 0, 0, 0, 0, 0, 0.57, 0, 0, 0.39, 0, 0, 0, 0, 0, 0, 0, 0},
    {0.81, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.12, 0, 0, 0, 0, 0, 0.08, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
    {0.14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.86, 0, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0},
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
    {0.29, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.71, 0, 0, 0}};

void pageit(Pentry q[MAXPROCESSES]) {
  static bool initialised = false;
  static int prev[MAXPROCESSES], tick = 1;
  static int row_sum[MAXPROCESSES][MAXPROCPAGES];
  static int prediction[MAXPROCESSES][MAXPROCPAGES][MAXPROCPAGES];
  bool swap[MAXPROCPAGES] = {false};
  if (!initialised) {
    for (int i = 0; i < MAXPROCESSES; i++)
      prev[i] = -1;
    memset(row_sum, 0, sizeof(row_sum));
    memset(prediction, 0, sizeof(prediction));
    initialised = true;
  }
  for (int proc = 0; proc < MAXPROCESSES; proc++)
    if (q[proc].active) {
      int curr = q[proc].pc / PAGESIZE;
      if (prev[proc] != -1 && prev[proc] != curr) {
        row_sum[proc][prev[proc]]++;
        prediction[proc][prev[proc]][curr]++;
      }
      prev[proc] = curr;
      swap[curr] = true;
      if (tick > PAGEWAIT && row_sum[proc][curr]) {
        for (int i = 0; i < MAXPROCPAGES; i++)
          if ((double)prediction[proc][curr][i] / row_sum[proc][curr]) {
            swap[i] = true;
            if (row_sum[proc][i])
              for (int j = 0; j < MAXPROCPAGES; j++)
                if ((double)prediction[proc][i][j] / row_sum[proc][i])
                  swap[j] = true;
          }
      } else {
        for (int i = 0; i < MAXPROCPAGES; i++)
          if (transition[curr][i]) {
            swap[i] = true;
            if (transition[curr][i] > 0.9)
              for (int j = 0; j < MAXPROCPAGES; j++)
                if (transition[i][j] * transition[curr][i] > 0.025)
                  swap[j] = true;
          }
      }
      for (int i = 0; i < q[proc].npages; i++)
        if (!swap[i] && q[proc].pages[i])
          pageout(proc, i);
      if (!q[proc].pages[curr])
        pagein(proc, curr);
      for (int i = 0; i < q[proc].npages; i++)
        if (swap[i] && !q[proc].pages[i])
          pagein(proc, i);
      memset(swap, false, sizeof(swap));
    }
  tick++;
}