A poc for fixed point calculations

fixed.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+
+typedef int fixed;
+#define FIXD (sizeof(fixed)*4)
+
+fixed mpy(fixed a, fixed b) {
+    return (fixed) (((long)a * (long)b) >> FIXD);
+}
+
+fixed div(fixed a, fixed b) {
+    return (fixed) (((long)a << FIXD) / b);
+}
+
+fixed add(fixed a, fixed b) {
+    return a + b;
+}
+
+fixed sub(fixed a, fixed b)  {
+    return a - b;
+}
+
+fixed fromdouble(double a) {
+    return (fixed) (a * (long)(1 << FIXD));
+}
+
+double todouble(fixed a) {
+    return (double)a / (long)(1 << FIXD);
+}
+
+int main( int argc, char *argv[] ) {
+
+    double af = 1.0f;
+    fixed a = fromdouble(af);
+    double bf = 2.0f;
+    fixed b = fromdouble(bf);
+
+    fixed c = div(a,b);
+    c = div(c,b);
+    double cf = todouble(c);
+
+    printf("%f\n",cf);
+
+    printf("%f\n",todouble(1));
+
+	return 0;
+}