1-bit branch predictor

#include <stdio.h>
#include <stdlib.h>

/*  For 2-bit Counter */
#define k 5
#define entry pow(2,k)  //   entry = 2^k

/*   Parameters   */
#define Taken    1
#define NonTaken 0

/*      Declare Variables      */
int Branch_Prediction_Buffer[(int)entry];
int Hit = 0 , Total = 0;       //   Record for success of conditional branch
int mapping = 0;

/*   Functions    */
unsigned long Hex2Dec(char *ch)
{
    int i,j=0, temp = 0;
    unsigned long   sum = 0 ;
    if( ch[1] == 10 )   return 0;
    for(i=7 ; i>=0 ; i--)
    {
            temp = ( ch[i] >= '0' && ch[i] <= '9' )? ch[i] - '0' : ( ch[i] >= 'a' && ch[i] <= 'e')? (ch[i] - 'a') +10 : 0;
            sum += temp << (j++*4);
    }
    return sum;
}

int main(int argc, char *argv[])
{
  char now_buf[20] = {0} , next_buf[20] = {0} , type_buf[10] = {0} ;
  int type ;
  int i =1, PCnow = 0, PCnext = 1;
  int Evaluation = 0 , Predict ;
  float Prediction_Rate;

  /*  Initialize Buffer  */
  int j;
  for(j=0;j<entry;j++)   Branch_Prediction_Buffer[j] = NonTaken;

  /* Open files */
  FILE *Now_ins, *Next_ins, *Ins_type;
  Now_ins = fopen("Path_pc_now.txt","r");
  Next_ins = fopen("Path_pc_next.txt","r");
  Ins_type = fopen("Path_type.txt","r");   // 1 is for conditional branch , SKIP if type is not 1

  /*    Main loop   */
  while(1)
  {
      /*    Read data   */
      fgets(now_buf , 20 , Now_ins);
      fgets(type_buf , 10 , Ins_type);
      fgets(next_buf , 20 , Next_ins);

      /*  Convert to dec  */
      type = atoi(type_buf);
      PCnow = Hex2Dec(now_buf);
      PCnext = Hex2Dec(next_buf);

      /*  Last data  */
      if(PCnext == 0)      break;

      /*  Prediction  */
       if(type != 1)    ;
       else
       {
              Evaluation = (PCnext - PCnow == 4)? NonTaken : Taken;
              mapping = (PCnow>>2) % (1<<k);
              Total++;

              Predict = Branch_Prediction_Buffer[mapping] ;
              printf("i=%3d state=%d mapping=%2d pc:%d p:%d e:%d\n",i,Branch_Prediction_Buffer[mapping],mapping,PCnow,Predict,Evaluation);
              //printf("pc:%d p:%d e:%d\n",PCnow,Predict,Evaluation);
              if( Predict == Evaluation )
              {
                  Hit++;
                  if( Predict == Taken )  Branch_Prediction_Buffer[mapping]++;
                  else                    Branch_Prediction_Buffer[mapping]--;
              }
              else
              {
                  if( Predict == Taken )  Branch_Prediction_Buffer[mapping]--;
                  else                    Branch_Prediction_Buffer[mapping]++;
              }

              if( Branch_Prediction_Buffer[mapping] > Taken )          Branch_Prediction_Buffer[mapping] = Taken;
              else if( Branch_Prediction_Buffer[mapping] < NonTaken )  Branch_Prediction_Buffer[mapping] = NonTaken;
       }
       i++;

  }
  printf("Hit:%d Missed:%d  Prediction Rate:%.2f%%\n",Hit,Total-Hit,(float)Hit/Total*100);

  /*  Close files  */
  fclose(Now_ins);
  fclose(Next_ins);
  fclose(Ins_type);
  system("PAUSE");
  return 0;
}