Check in code for new random number generator

luprex/experiments/bigid.cpp

@@ -0,0 +1,43 @@
+#include <iostream>
+#include <cstdint>
+
+bool storable(int64_t n) {
+    double d = n;
+    int64_t n1 = int64_t(d);
+    return n1 == n;
+}
+
+
+// Find the biggest number where the number is storable,
+// and all numbers smaller are also storable.
+int64_t find_biggest() {
+    int64_t v = 256;
+    int64_t best = 256;
+    while (true) {
+        for (int i = 0; i < 100; i++) {
+            if (!storable(v - i)) {
+                return best;
+            }
+        }
+        best = v;
+        v <<= 1;
+    }
+}
+
+    
+int main(int argc, char **argv) {
+    int64_t best = find_biggest();
+
+    printf("%016lx   ", best);
+    for (int i = -12; i <= 12; i++) {
+        if (i == 0) printf("  ");
+        if (storable(best + i)) {
+            printf("* ");
+        } else {
+            printf("- ");
+        }
+        if (i == 0) printf("  ");
+    }
+    printf("\n");
+    return 0;
+}