diff --git a/sipsi-8.py b/sipsi-8.py
index b459c04..7c5f4b8 100644
--- a/sipsi-8.py
+++ b/sipsi-8.py
@@ -116,8 +116,12 @@ def step():
 
 	# 0nnn call_machine
 	elif high_byte >> 4 == 0:
-		print("%03x: Can't call machine language!" % (ip - 2))
-		sys.exit(1)
+		# Our own non-standard debug
+		if high_byte & 0xf == 0x1:
+			print(low_byte & 0xf, data_registers[low_byte & 0xf])
+		else:
+			print("%03x: Can't call machine language!" % (ip - 2))
+			sys.exit(1)
 
 	# 1nnn jmp nnn
 	elif high_byte >> 4 == 1: