diff --git a/src/mult-test.py b/src/mult-test.py
new file mode 100644
index 0000000..4887d00
--- /dev/null
+++ b/src/mult-test.py
@@ -0,0 +1,27 @@
+import multiply as mlt
+
+top_value = int("0b" + input("Top value (in binary): "), 2)
+m = int(input("Method: "))
+
+total_iterations = (top_value + 1) ** 2
+print(f"Total test amount: {top_value + 1}^2 = {total_iterations}")
+
+errors = []
+
+for x in range(top_value):
+    for y in range(top_value):
+        n = max([len(bin(i)[2:]) for i in (x, y)])
+        expected_result = mlt.al(bin(x*y)[2:], 2*n)
+
+        _, r = mlt.multiply(n, x, y, m)
+
+        if r == expected_result:
+            print(f"{str(x*top_value+y).rjust(len(str(total_iterations)))}/{total_iterations}", end = "\r")
+        else:
+            errors.append([x, y, expected_result, r])
+            print(f"Failed at {x}*{y}; expected {expected_result} but got {r}!")
+
+if len(errors) == 0:
+    print("Testing finished, no miscalculations detected.\nIt's safe to use!")
+else:
+    print("Testing failed with {len(errors)} errors.")
diff --git a/src/multiply.py b/src/multiply.py
index 124c1ad..7c8f749 100644
--- a/src/multiply.py
+++ b/src/multiply.py
@@ -8,52 +8,90 @@ def align_binary_to_right(value, size):
 
 al = align_binary_to_right
 
-def multiply(x, y, method):
+def multiply(n, x, y, method):
+    '''
+    this method can be used to:
+    - get step-by-step binary multiplication data using different methods;
+    - get just the end result of binary multiplication;
+
+    it takes 4 arguments:
+    n - (int) base register bit depth
+    x - (int) value for X operand
+    y - (int) value for Y operand
+    method - (int) which method to use to perform multiplication
+
+    it returns 2 items:
+    - (list) table with step-by-step operations and descriptions
+    - (str)  binary representation of the result
+
+    Methods fully supported: №4
+    '''
+
     if method == 4:
-        n = len(bin(x)[2:]) # base registry bit length, usually written as n
-
         # every table line has registers like so: RG1, RG3, RG2
-        data_table = [[["0"*(2*n+1), "0" + bin(y)[2:] + "0"*n, bin(x)[2:], "-"]]*2]
+        data_table = [[["0", "0"*(2*n+1), "0" + al(bin(y)[2:], n) + "0"*n, al(bin(x)[2:], n), "-"]]*2]
 
-        while int('0b' + data_table[-1][-1][2], 2) != 0:
+        # iteration number
+        i = 0
+
+        while int('0b' + data_table[-1][-1][3], 2) != 0:
             data_table.append([])
+            i += 1
 
-            if data_table[-2][-1][2][0] == "1":
+            if data_table[-2][-1][3][0] == "1":
                 data_table[-1].append([
-                    al(bin(int("0b"+data_table[-2][-1][0], 2) + int("0b"+data_table[-2][-1][1], 2))[-(2*n+1):], 2*n+1), # RG1 + RG3
-                    data_table[-2][-1][1],
+                    i,
+                    al(bin(int("0b"+data_table[-2][-1][1], 2) + int("0b"+data_table[-2][-1][2], 2))[-(2*n+1):], 2*n+1), # RG1 + RG3
                     data_table[-2][-1][2],
+                    data_table[-2][-1][3],
                     "RG1+RG3"
                 ])
 
                 data_table[-1].append([
-                    data_table[-1][-1][0],
-                    '0' + data_table[-1][-1][1][:-1], # 0.r(RG3)
-                    data_table[-1][-1][2][1:] + '0', # l(RG2).0
+                    i,
+                    data_table[-1][-1][1],
+                    '0' + data_table[-1][-1][2][:-1], # 0.r(RG3)
+                    data_table[-1][-1][3][1:] + '0', # l(RG2).0
                     "0.r(RG3), l(RG2).0"
                 ])
 
             else:
                 data_table[-1].append([
-                    data_table[-2][-1][0],
-                    '0' + data_table[-2][-1][1][:-1], # 0.r(RG3)
-                    data_table[-2][-1][2][1:] + '0', # l(RG2).0
+                    i,
+                    data_table[-2][-1][1],
+                    '0' + data_table[-2][-1][2][:-1], # 0.r(RG3)
+                    data_table[-2][-1][3][1:] + '0', # l(RG2).0
                     "0.r(RG3), l(RG2).0"
                 ])
 
-        return data_table
+        return data_table, data_table[-1][-1][1][:-1]
+
 
 if __name__ == "__main__":
-    x = int("0b" + input("X: "), 2)
-    y = int("0b" + input("Y: "), 2)
+    # a fully functional reference
+    # implementation for this library
+    # is provided below
+
+    raw_x = input("X: ")
+    raw_y = input("Y: ")
+
+    if len(raw_x) == len(raw_y):
+        n = len(raw_x)
+    else:
+        n = int(input("n: "))
+
+    x = int("0b" + raw_x, 2)
+    y = int("0b" + raw_y, 2)
+
     method = int(input("Method: "))
-    dt = multiply(x, y, method)
+
+    dt, result = multiply(n, x, y, method)
 
     from lib.prettytable import PrettyTable
     pt = PrettyTable()
-    pt.field_names = ["RG1", "RG3", "RG2", "Operations"]
+    pt.field_names = ["Iteration", "RG1", "RG3", "RG2", "Operations"]
 
-    for i in dt[1:]:
+    for i in dt:
         for j in range(len(i)):
             if j+1 == len(i):
                 pt.add_row(i[j], divider = True)
@@ -61,3 +99,4 @@ if __name__ == "__main__":
                 pt.add_row(i[j])
 
     print(pt)
+    print(f"Result: {result}")