mirror of
https://github.com/elliotnunn/tbxi-patches.git
synced 2024-06-07 18:29:31 +00:00
101 lines
3.8 KiB
Python
Executable File
101 lines
3.8 KiB
Python
Executable File
#!/usr/bin/env python3
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import patch_common
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from os import path
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import os
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import struct
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import shutil
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import re
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import binascii
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src, cleanup = patch_common.get_src(desc='''
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Enable booting from ATA disks without an Apple_Driver_ATA partition. This is
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done by patching the ROM-based .ATALoad DRVR to fall back on the ROM-based
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.ATADisk DRVR when initially scanning a disk. The .ATADisk is added to the ROM
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if missing. The disk still needs an Apple Partition Map.
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''')
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# long BOOT(void *DRVR, void *PartMapEntry, long flags)
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# C calling convention: args pushed in reverse order and not popped by function, return value in d0
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def find_BOOT(code):
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for i in range(0, len(code), 2):
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if code[i:i+4] == b'BOOT': # MOVE.L 'BOOT',D0 --or-- MOVE.L 'BOOT',-(SP)
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for j in reversed(range(0, i, 2)):
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# Count backwards and look for the target of *any* JSR, which is the start of the func
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for k in range(0, len(code), 2):
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if code[k:k+2] == b'\x4E\xBA': # JSR opcode
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if k+2 + struct.unpack('>h', code[k+2:k+4])[0] == j:
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return j
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raise ValueError('Function BOOT not found')
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def find_InitDevice(code):
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for i in range(0, len(code), 2):
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# checking Driver Descriptor Map magic number (there are two but this one always first)
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if code[i:i+2] == b'ER':
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for j in reversed(range(0, i, 2)):
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if code[j:j+2] == b'NV': # LINK A6,#$xxxx
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return j
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raise ValueError('Function InitDevice not found')
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def patch_ataload(code):
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code = bytearray(code)
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new = len(code) # boundary between old and new code
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# Parse the DumpObj'd file
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with open(path.join(path.dirname(__file__), 'ATALoad.dmp')) as f:
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for l in f:
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m = re.match(r'^[0-9A-F]{8}: ([0-9A-F ]+)', l) or re.match('^ {13}([0-9A-F][0-9A-F ]*)', l)
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if m:
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code.extend(binascii.unhexlify(m.group(1).replace(' ', '')))
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InitDevice = find_InitDevice(code[:new])
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BOOT = find_BOOT(code[:new])
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print('ATALoad patch: InitDevice=0x%X, NewInitDevice=0x%X, BOOT=0x%X' % (InitDevice, new, BOOT))
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# "Link" the new code into the old
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for i in range(new, len(code), 2):
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if code[i:i+4] == b'Nsrt':
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code[i:i+4] = code[InitDevice:InitDevice+4] # copy the first LINK from the original function
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code[InitDevice:InitDevice+2] = b'\x60\x00' # BRA.W opcode, to...
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code[InitDevice+2:InitDevice+4] = struct.pack('>h', new - (InitDevice+2)) # ...the start of the new code
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if code[i:i+2] == b'ID': # reference to original InitDevice, skipping the mangled 4-byte LINK
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code[i:i+2] = struct.pack('>h', (InitDevice+4) - i)
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if code[i:i+2] == b'BT': # reference to BOOT function
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code[i:i+2] = struct.pack('>h', BOOT - i)
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return bytes(code)
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for (parent, folders, files) in os.walk(src):
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folders.sort(); files.sort() # make it kinda deterministic
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for filename in files:
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full = path.join(src, parent, filename)
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if filename == 'Romfile':
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ataload = path.join(src, parent, 'Rsrc', 'DRVR_-20175_ATALoad')
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atadisk = path.join(src, parent, 'Rsrc', 'DRVR_53_ATADisk')
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if path.exists(ataload):
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code = open(ataload, 'rb').read()
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code = patch_ataload(code)
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open(ataload, 'wb').write(code)
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if not path.exists(atadisk):
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with open(full, 'a') as f: # append to Romfile
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f.write('\ntype=DRVR id=53 name=.ATADisk src=Rsrc/DRVR_53_ATADisk # inserted by ataboot.py\n')
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print('ATALoad patch: using .ATADisk DRVR from Drive Setup 2.1')
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shutil.copy(path.join(path.dirname(__file__), 'DRVR_53_ATADisk'), atadisk)
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cleanup()
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