mirror of https://github.com/PrimeDecomp/prime.git
53 lines
1.6 KiB
Python
Executable File
53 lines
1.6 KiB
Python
Executable File
#! /usr/bin/env python3
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# Written by Ethan Roseman (ethteck)
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# MIT License
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# Copyright 2021
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# Modified by EpochFlame
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import argparse
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# Byte sequences
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BLR_BYTE_SEQ = b"\x4E\x80\x00\x20"
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MTLR_BYTE_SEQ = b"\x7C\x08\x03\xA6"
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# Example invocation: ./frank.py vanilla.o target.o
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parser = argparse.ArgumentParser()
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parser.add_argument("vanilla", help="Path to the vanilla object", type=argparse.FileType('rb'))
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parser.add_argument("target", help="Path to the target object (to write)")
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args = parser.parse_args()
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# Read contents into bytearrays and close files
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vanilla_bytes = args.vanilla.read()
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args.vanilla.close()
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# Reunify mtlr/blr instructions, shifting intermediary instructions up
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idx = 0
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while idx < len(vanilla_bytes):
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# Find mtlr position
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mtlr_found_pos = vanilla_bytes.find(MTLR_BYTE_SEQ, idx)
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if mtlr_found_pos == -1:
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break # break while loop when no targets remain
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if mtlr_found_pos % 4 != 0: # check 4-byte alignment
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idx += 4
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continue
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# Find paired blr position
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blr_found_pos = vanilla_bytes.find(BLR_BYTE_SEQ, mtlr_found_pos)
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if blr_found_pos == -1:
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break # break while loop when no targets remain
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if blr_found_pos % 4 != 0: # check 4-byte alignment
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idx += 4
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continue
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if mtlr_found_pos + 4 == blr_found_pos:
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idx += 4
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continue # continue if mtlr is followed directly by blr
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vanilla_bytes = vanilla_bytes[:mtlr_found_pos] + vanilla_bytes[mtlr_found_pos+4:blr_found_pos] + vanilla_bytes[mtlr_found_pos:mtlr_found_pos+4] + vanilla_bytes[blr_found_pos:]
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idx = mtlr_found_pos + len(MTLR_BYTE_SEQ)
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with open(args.target, "wb") as f:
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f.write(vanilla_bytes)
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