Add a post assembly script to round up ROM size (fixes ROM banking on some emulator)

1 files changed, 34 insertions, 0 deletions

diff --git a/scripts/round-rom-size.py b/scripts/round-rom-size.py
new file mode 100644
index 0000000..a59a11f
--- /dev/null
+++ b/scripts/round-rom-size.py
@@ -0,0 +1,34 @@
+import sys
+import os
+
+if len(sys.argv) != 2:
+    raise ValueError("Rom file must be specified as first argument")
+
+rom_filename = sys.argv[1]
+current_filesize = os.path.getsize(rom_filename)
+
+i = 0
+for n in range(0, 9):
+    if current_filesize <= 32768 * (1 << n):
+        break
+    i += 1
+
+missing = (32768 * (1 << i)) - current_filesize
+
+print("Original file size =", current_filesize, "bytes")
+print("ROM size =", hex(i), "({} bytes)".format(32768 * (1 << i)))
+
+rom_file = open(rom_filename, 'r+b')
+
+rom_file.seek(0x148)
+
+rom_file.write(bytes(bytearray([i])))
+
+rom_file.close()
+
+rom_file = open(rom_filename, 'a+b')
+
+
+rom_file.write(bytes(bytearray([0]*missing)))
+
+rom_file.close()