oot/fixbaserom.py
Anghelo Carvajal 9c2ad0c60b
fixbaserom.py: Add support to v64 format and improve performance (#629)
* Add byte swap for v64 files

Signed-off-by: angie <angheloalf95@gmail.com>

* Reduce `len` function calls

Signed-off-by: angie <angheloalf95@gmail.com>

* Optimze a bit the byte-swapped v64 format

Signed-off-by: angie <angheloalf95@gmail.com>

* Strip the overdump before doing the byte-swap

The previous way wasted time by byte-swapping data that would be discarded anyway.

Signed-off-by: angie <angheloalf95@gmail.com>

* Swap twice the bytes per cycle to improve performance

Signed-off-by: angie <angheloalf95@gmail.com>

* Read and write 16 bytes at a time and specify explicit endianness

Reading more bytes per cycle allow to speed up the swapping proccess

Signed-off-by: angie <angheloalf95@gmail.com>

* Add v64 compatibility in the Readme

Signed-off-by: angie <angheloalf95@gmail.com>

* Read whole file as little endian and write it as big endian without the loop

Signed-off-by: angie <angheloalf95@gmail.com>
2021-01-14 15:14:33 -05:00

84 lines
2.5 KiB
Python

from os import path
import sys
import struct
import hashlib
def get_str_hash(byte_array):
return str(hashlib.md5(byte_array).hexdigest())
# If the baserom exists and is correct, we don't need to change anything
if path.exists("baserom.z64"):
with open("baserom.z64", mode="rb") as file:
fileContent = bytearray(file.read())
if get_str_hash(fileContent) == "f0b7f35375f9cc8ca1b2d59d78e35405":
print("Found valid baserom - exiting early")
sys.exit(0)
# Determine if we have a ROM file
romFileName = ""
if path.exists("baserom_original.z64"):
romFileName = "baserom_original.z64"
elif path.exists("baserom_original.n64"):
romFileName = "baserom_original.n64"
elif path.exists("baserom_original.v64"):
romFileName = "baserom_original.v64"
else:
print("Error: Could not find baserom_original.z64/baserom_original.n64/baserom_original.v64.")
sys.exit(1)
# Read in the original ROM
print("File '" + romFileName + "' found.")
with open(romFileName, mode="rb") as file:
fileContent = bytearray(file.read())
# Strip the overdump
print("Stripping overdump...")
fileContent = fileContent[0:0x3600000]
fileContentLen = len(fileContent)
# Check if ROM needs to be byte/word swapped
# Little-endian
if fileContent[0] == 0x40:
# Word Swap ROM
print("ROM needs to be word swapped...")
words = str(int(fileContentLen/4))
little_byte_format = "<" + words + "I"
big_byte_format = ">" + words + "I"
tmp = struct.unpack_from(little_byte_format, fileContent, 0)
struct.pack_into(big_byte_format, fileContent, 0, *tmp)
print("Word swapping done.")
# Byte-swapped
elif fileContent[0] == 0x37:
# Byte Swap ROM
print("ROM needs to be byte swapped...")
halfwords = str(int(fileContentLen/2))
little_byte_format = "<" + halfwords + "H"
big_byte_format = ">" + halfwords + "H"
tmp = struct.unpack_from(little_byte_format, fileContent, 0)
struct.pack_into(big_byte_format, fileContent, 0, *tmp)
print("Byte swapping done.")
# Patch the header
print("Patching header...")
fileContent[0x3E] = 0x50
# Check to see if the ROM is a "vanilla" Debug ROM
str_hash = get_str_hash(bytearray(fileContent))
if str_hash != "f0b7f35375f9cc8ca1b2d59d78e35405":
print("Error: Expected a hash of f0b7f35375f9cc8ca1b2d59d78e35405 but got " + str_hash + ". " +
"The baserom has probably been tampered, find a new one")
sys.exit(1)
# Write out our new ROM
print("Writing new ROM 'baserom.z64'.")
with open("baserom.z64", mode="wb") as file:
file.write(bytes(fileContent))
print("Done!")