MC68HC11 Quadratic Equation

[junkbonkin]

I Am trying to write a small program to solve the quadratic equation and i was wondering if anyone could help the numbers are A=1 B=4 and C=5 thanks for your help in advance and also does anyone know of a good free ware 68hc11 emulator i had THRsim11 but the trial is almost over thank you in advance

[junkbonkin]

unfortunately i am using one that can only take mnemonic code or opcode but thank you for the help

[bigmac]

Hello,

Assuming you have resources to accommodate floating point mathematics, the following untested function should give the solutions to the quadradic equation, for both real and complex cases.

#include "math.h"

/* Global variables for result */
double r1, i1;  // First solution
double r2, i2;  // Second solution

void quadratic (double a, double b, double c)
{
  double t;

  b = b/a;
  c = c/a;

  t = b*b/2 - c;

  if (t < 0)  {
     /* Complex solution */
     r1 = -0.5*b;
     i1 = sqrt(-t);
     r2 = r1;
     i2 = -i1;
  }
  else {
     /* Real solution */
     t = sqrt(t);
     r1 = -0.5*b + t;
     i1 = 0;
     r2 = -0.5*b - t;
     i2 = 0;
  }
}

For the coefficients given in your post, the solution will be complex -

-2+j1, -2-j1

Regards,

Mac