diff --git a/c/experimental/fltres.c b/c/experimental/fltres.c
new file mode 100644
index 000000000..621e61082
--- /dev/null
+++ b/c/experimental/fltres.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+static void show(long long i) {
+	double d = (double) i;
+	long long j = (long long) d;
+	printf("%016llx %lld %lf %016llx\n", i, i, d, j);
+}
+
+int main() {
+	show(0x7ffffffffffff9ff);
+	show(0x7ffffffffffffa00);
+	show(0x7ffffffffffffbff);
+	show(0x7ffffffffffffc00);
+	show(0x7ffffffffffffdff);
+	show(0x7ffffffffffffe00);
+	show(0x7ffffffffffffffe);
+	show(0x7fffffffffffffff);
+
+	return 0;
+}