cordic.c

cordic implementation in vhdl&c

//-------------+--------------------------------------------------------------
// Description | Evaluation of sin & cos using cordic algorithm.
//
// History     |
//##############################################################################
// Author : Aviral Mittal
// [e-mail]
//##############################################################################

#define NULL (0)
#include <stdio.h>
#include <string.h>
#include <math.h>

float str2float(char * argv[]);
void PrintHelpMess();
void HandleArgs(int argc);
float msin(float angle);

int main (int argc, char * argv[])
{
  float angle;
  float sinval;
  float cosval;
  HandleArgs(argc);
  angle = str2float(argv);
  if(angle <0 || angle>90)
  {
    printf("ERROR! Input(%f) out of bounds, should be >=0 and <=90\n",angle);
    exit(-1);
  }
  sinval = msin(angle);
  printf("cos eval\n");
  //cosval = msin(90-angle);
  printf("Input Angle is %f,%f(rad), sinval = %f, cosval = %f\n",angle,(angle*3.141592)/180,sinval,cosval);
  printf("Input Angle is %f,%f(rad), sinval = %f, cosval = %f\n",angle,(angle*3.141592)/180,sin((angle*3.141592)/180),cos((angle*3.141592)/180));
}// int main (int argc, char * argv[])

float str2float(char * argv[])
{
char whole[32];
char *pwhole;
char deci[32];
char *pdeci;
int wend = 0;
int ww;
int wd;
int ii;
int re = 1;
int co = 0;
float ff;
        wend = 0;
        ww = 0;
        wd = 0;
        pwhole = &whole[0];
        pdeci = &deci[0];
        ff = 0.0;
        while(*argv[1]) 
        {
          if(*argv[1] == 46)//look for decimal i.e a dot '.'
          {
            wend = 1;
          }
          else
          {
            if(wend)
            {
              *pdeci = *argv[1]-48;
              //printf("%d\n",*pdeci);
              pdeci++;
              wd++;
            }
            else
            {
              *pwhole = *argv[1]-48;
              //printf("%d\n",*pwhole);
              pwhole++;
              ww++;
            }
          }

          argv[1]++;
        }// while(*argv[1]) 
        *pwhole = '\0';
        *pdeci = '\0';
        pwhole--;
        for(ii=0;ii<ww;ii++)
        {
          //printf("%d\n",*pwhole);
          ff = ff + *pwhole*pow(10,ii);
          pwhole--;
        }
        pdeci = pdeci - wd;
        for(ii=1;ii<wd+1;ii++)
        {
          //printf("%d\n",*pdeci);
          ff = ff + *pdeci*pow(10,-ii);
          pdeci++;
        }
        return ff;
}// float str2float(char * argv[])

void PrintHelpMess()
{
  printf("ERROR! No Input. One expected\n");
  printf("Usage> a.out <angle between 0 and 90>\n");
  printf("Example> a.out 54\n");
}

void HandleArgs(int argc)
{
switch(argc)
  {
    case 1 :
      {
        PrintHelpMess();
        exit(-1);
      }// case 1 :
    case 2 :
      {
        break;
      }// case 2 :
    default:
      {
        printf("ERROR! Too many args at command line. Exiting....\n");
        exit(-1);
      }
  }// switch(argc)
}// void HandleArgs(int argc)

float msin(float angle)
{
  int itt = 5;
  float re = 0.60725;
  //float re = 1.0;
  float im = 0;

  float new_re;
  float new_im;
  float mag;
  float angles[13];
  float accum;
  angles[0] = 45.0;
  angles[1] = 26.56505;
  angles[2] = 14.03624;
  angles[3] = 7.12502;
  angles[4] = 3.57633;
  angles[5] = 1.78991;
  angles[6] = 0.89517;
  angles[7] = 0.44761;
  angles[8] = 0.22381;
  angles[9] = 0.111905;
  angles[10] = 0.055953;
  angles[11] = 0.027976;
  angles[12] = .0139882;

  accum = 0;
  for(itt=0;itt<13;itt++)
  {
    if(angle > accum)
    {
      accum = accum + angles[itt];
      new_re = re-im/pow(2,itt);
      new_im = im+re/pow(2,itt);
      printf("accum = %f,pow=%f\n",accum,pow(2,itt));
    }
    else 
    {
      accum = accum - angles[itt];
      new_re = re+im/pow(2,itt);
      new_im = im-re/pow(2,itt);
      printf("accum2 = %f,pow=%f\n",accum,pow(2,itt));
    }
    re=new_re;
    im=new_im;
    mag = pow((pow(new_re,2) + pow(new_im,2)),0.5);
    printf("new_re = %f,new_im=%f,mag=%f,angle = %f\n",new_re,new_im,mag,angles[itt]);
  }
  //printf("cos = %f,sin=%f,angle(rad) = %f\n",new_re,new_im,(angle*3.141592)/180);

  return(new_im);
  
}// float msin(float angle)