1 files changed, 26 insertions, 0 deletions
diff --git a/tests/test_data.h b/tests/test_data.h
index fa32f529..6ff7b644 100644
--- a/tests/test_data.h
+++ b/tests/test_data.h
@@ -14,6 +14,11 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
+#include "../src/ieee_float.h"
+#include "../src/soft_float.h"
+
+#include <assert.h>
+#include <math.h>
 #include <stdint.h>
 #include <string.h>
 
@@ -54,3 +59,24 @@ double_from_rep(const uint64_t rep)
 	memcpy(&d, &rep, sizeof(d));
 	return d;
 }
+
+/// Return the distance between two doubles in ULPs
+static uint64_t
+ulp_distance(const double a, const double b)
+{
+	assert(a >= 0.0);
+	assert(b >= 0.0);
+
+	if (a == b) {
+		return 0;
+	} else if (isnan(a) || isnan(b)) {
+		return UINT64_MAX;
+	} else if (isinf(a) || isinf(b)) {
+		return UINT64_MAX;
+	}
+
+	const uint64_t ia = double_to_rep(a);
+	const uint64_t ib = double_to_rep(b);
+
+	return ia > ib ? ia - ib : ib - ia;
+}