added tests as prepared by oliver

test/ref/mandel.c

@@ -0,0 +1,84 @@
+/*
+  !!DESCRIPTION!! mandelbrot test program
+  !!ORIGIN!!      testsuite
+  !!LICENCE!!     Public Domain
+  !!AUTHOR!!      Groepaz/Hitmen
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+static unsigned short SCREEN_X;
+static unsigned char  SCREEN_Y;
+
+#define MAXCOL     8
+
+#define maxiterations 16
+
+#define fpshift (12)
+
+#define tofp(_x)        ((_x)<<fpshift)
+#define fromfp(_x)      ((_x)>>fpshift)
+#define fpabs(_x)       (abs(_x))
+
+#define mulfp(_a,_b)    ((((signed long)_a)*(_b))>>fpshift)
+#define divfp(_a,_b)    ((((signed long)_a)<<fpshift)/(_b))
+
+unsigned char dither[MAXCOL]={" .*o+0%#"};
+
+void mandelbrot(signed short x1,signed short y1,signed short x2,signed short y2)
+{
+register signed short  r,r1,i;
+register unsigned char count;
+register signed short xs,ys,xx,yy;
+register signed short x;
+register unsigned char y;
+
+        /* calc stepwidth */
+        xs=((x2-x1)/(SCREEN_X));
+        ys=((y2-y1)/(SCREEN_Y));
+
+        yy=y1;
+        for(y = 0; y < (SCREEN_Y); ++y)
+        {
+                yy+=ys; xx=x1;
+                for(x = 0; x < (SCREEN_X); ++x)
+                {
+                    xx+=xs;
+                    /* do iterations */
+                    r=0;i=0;
+                    for(count=0;(count<maxiterations)&&
+                                (fpabs(r)<tofp(2))&&
+                                (fpabs(i)<tofp(2))
+                                ;++count)
+                    {
+                            r1 = (mulfp(r,r)-mulfp(i,i))+xx;
+                            /* i = (mulfp(mulfp(r,i),tofp(2)))+yy; */
+                            i = (((signed long)r*i)>>(fpshift-1))+yy;
+                            r=r1;
+                    }
+                    if(count==maxiterations)
+                    {
+                            printf(" ");
+                    }
+                    else
+                    {
+                            printf("%c",dither[(count%MAXCOL)]);
+                    }
+                }
+                    printf("\n");
+        }
+}
+
+int main (void)
+{
+    SCREEN_X = 80;
+    SCREEN_Y = 40;
+
+    /* calc mandelbrot set */
+    mandelbrot(tofp(-2),tofp(-2),tofp(2),tofp(2));
+
+    /* Done */
+    return 0;
+}
+