diff --git a/generate_act_format.py b/generate_act_format.py
index 4104159..db0d2d8 100644
--- a/generate_act_format.py
+++ b/generate_act_format.py
@@ -31,22 +31,11 @@ desired_names = {
 }
 
 
-@click.command()
-@click.argument("opcodes_file", type=click.File("r"))
-def generate_act_format(opcodes_file):
-    """
-    Parses an OPCODES_FILE and outputs opcodes in a format expected by ACT.
-    This is also just a bunch of regexes slapped together.
-
-    Outputs to stdout.
-
-    Example:
-
-    python generate_act_format.py Ipcs.h
-    """
+def write_act_format(opcodes_lines):
+    output_lines = []
     opcode_mapping = dict()
 
-    for line in opcodes_file.readlines():
+    for line in opcodes_lines:
         match_groups = re.findall(r"^\s*([^\/].*)=\s*(.*),\s*\/\/.*$", line)
         if len(match_groups) != 1:
             continue
@@ -66,11 +55,31 @@ def generate_act_format(opcodes_file):
             desired = name
         opcodes = opcode_mapping[name]
         if len(opcodes) == 1:
-            print(f"{desired}|{opcodes[0]:x}")
+            output_lines.append(f"{desired}|{opcodes[0]:x}")
         elif len(opcodes) > 1:
-            print(f'{desired}|{[f"{opcode:x}" for opcode in opcodes]}')
+            output_lines.append(f'{desired}|{[f"{opcode:x}" for opcode in opcodes]}')
         else:
-            print(f"{desired}|???")
+            output_lines.append(f"{desired}|???")
+
+    return output_lines
+
+
+@click.command()
+@click.argument("opcodes_file", type=click.File("r"))
+def generate_act_format(opcodes_file):
+    """
+    Parses an OPCODES_FILE and outputs opcodes in a format expected by ACT.
+    This is also just a bunch of regexes slapped together.
+
+    Outputs to stdout.
+
+    Example:
+
+    python generate_act_format.py Ipcs.h
+    """
+    lines = write_act_format(opcodes_file.readlines())
+    for line in lines:
+        print(line)
 
 
 if __name__ == "__main__":
diff --git a/vtable_diff.py b/vtable_diff.py
index 690922a..54664b4 100644
--- a/vtable_diff.py
+++ b/vtable_diff.py
@@ -78,6 +78,29 @@ def find_opcode_matches(old_opcodes_db, new_opcodes_db):
     return matches
 
 
+def diff_exes(old_exe, new_exe):
+    old_opcodes_db = extract_opcode_data(old_exe)
+    new_opcodes_db = extract_opcode_data(new_exe)
+
+    if len(old_opcodes_db) != len(new_opcodes_db):
+        eprint(
+            f"WARNING: vtables have different sizes: {len(old_opcodes_db)} != {len(new_opcodes_db)}. Matches may not be correct."
+        )
+
+    opcodes_found = find_opcode_matches(old_opcodes_db, new_opcodes_db)
+    opcodes_object = []
+
+    for old, new in opcodes_found:
+        opcodes_object.append(
+            {
+                "old": [hex(old)],
+                "new": [hex(new)],
+            }
+        )
+
+    return opcodes_object
+
+
 @click.command()
 @click.argument(
     "old_exe", type=click.Path(exists=True, dir_okay=False, resolve_path=True)
@@ -106,25 +129,7 @@ def vtable_diff(old_exe, new_exe):
 
     python vtable_diff.py ffxiv_dx11.old.exe ffxiv_dx11.new.exe > diff.json
     """
-    old_opcodes_db = extract_opcode_data(old_exe)
-    new_opcodes_db = extract_opcode_data(new_exe)
-
-    if len(old_opcodes_db) != len(new_opcodes_db):
-        eprint(
-            f"WARNING: vtables have different sizes: {len(old_opcodes_db)} != {len(new_opcodes_db)}. Matches may not be correct."
-        )
-
-    opcodes_found = find_opcode_matches(old_opcodes_db, new_opcodes_db)
-    opcodes_object = []
-
-    for old, new in opcodes_found:
-        opcodes_object.append(
-            {
-                "old": [hex(old)],
-                "new": [hex(new)],
-            }
-        )
-
+    opcodes_object = diff_exes(old_exe, new_exe)
     print(json.dumps(opcodes_object, indent=2))