/* 
* Speedy Mandelbrot set main loop 
* On IBM Blue lightning 486, goes about 10% slower than fractint 19.5 
* On Intel Pentium 200MMX goes twice as fast as fractint!
* Timings based on time taken to calculate an image 320*200 with 20000
* iterations such that each pixel requires all 20000 iterations ie time taken 
* to calculate 1.28e9 iterations. This takes my Pentium 211.3 sec in Linux (and
* dos too using DJGPP. With this number of iterations, the time spent by
* fractint plotting pixels is completely insignificant (a fraction of a second
* so it is a fair comparison.
* flags -O3 -fomit-frame-pointer -ffast-math -funroll-loops -m486
* Yes, that is -m486! It goes quite a bit faster with this instead of 
* -mpentium which EGCS allows
* C compiler:EGCS-2.90.29 980515 (egcs-1.0.3 release)
* Hoppy 2/98
* r.hopkins@ic.ac.uk
*/

/* guess how to use it.... :-) */

unsigned int Mand (double initx, double inity, unsigned int iterations) {
    
    double cx,cy,xsq,ysq;
    unsigned int iter;
    
    cx=initx+initx*initx - inity*inity;   
    cy=inity+initx*inity+initx*inity; 
    
    for (iter=0;iter<iterations && (ysq=cy*cy)+(xsq=cx*cx)<4;iter++,cy=inity+cx*cy+cx*cy,cx=initx-ysq+xsq) ;
    return (iter);
}