diff --git a/joy/library.py b/joy/library.py
index 5d778d6..8ad7948 100644
--- a/joy/library.py
+++ b/joy/library.py
@@ -423,6 +423,19 @@ def take(stack):
 	return x, stack
 
 
+@inscribe
+@FunctionWrapper
+def gcd2(stack, expression, dictionary):
+    '''Compiled GCD function.'''
+    (v1, (v2, stack)) = stack
+    tos = True
+    while tos:
+        v3 = v2 % v1
+        tos = v3 > 0
+        (v1, (v2, stack)) = (v3, (v1, stack))
+    return (v2, stack), expression, dictionary
+
+
 @inscribe
 @SimpleFunctionWrapper
 def choice(stack):