#include  <bios.h>

/* Global */

int   SEED_x,SEED_y,SEED_z;

/*
      -------------------------------
         RANDOM  NUMBER  GENERATOR
      -------------------------------

      This random number generator has a cycle
      of about 7.6e12.  You can call it many
      times without reseeding.  Seed it manually
      by calling Seed or Clock_Seed.  Clock_Seed
      reads the biosclock and thus works only on
      DOS systems. The random number returned
      from Random lies between 0.0 and 1.0.
      The seed values for the x,y, and z portions
      of the generator are held externally.

      k.t. kilty

*/

void  Seed(int x,int y,int z)
{
      SEED_x=x; SEED_y=y; SEED_z=z;
} /* seeding random number gen */

void  Clock_Seed(void)
{
long  time,shift;
      time=biostime(0,0);
      shift=time/1000;
      shift=time-1000*shift;

      SEED_x=(int)shift;
      SEED_y=(int)shift-1;
      SEED_z=(int)shift-2;
}  /* Clock_Seed */

float Random(void)
{
/*   returns a random number between 0.0 and 1.0
     the generator cycle is 7.6e12 roughly  and
     the generator needs SEED_x,SEED_y and SEED_z
     to be kept in Global.  They provide a random
     reseeding on each call.*/

int   x_new,y_new,z_new;
float output;

      x_new=171*(SEED_x%177) - 2*(SEED_x/177);
      if (x_new<0) x_new+=30269;
      y_new=173*(SEED_y%177) - 2*(SEED_y/177);
      if (y_new<0) y_new+=30773;
      z_new=177*(SEED_z%185) - 2*(SEED_z/185);
      if (z_new<0) z_new+=32749;

      output = (float)x_new/30269.0 + (float)y_new/30773.0 +
	       (float)z_new/32749.0;
      output -= (int)output;
      SEED_x=x_new; SEED_y=y_new; SEED_z=z_new;

      return(output);
} /* random */