Jonah Barrington
Found on:
"Jonah Barrington's Squash"
Loader files:
ROM Header 1
Filename only
ROM Data 1
Autostart, loads and decrypts turbo loader
ROM Header 2
Filename only
ROM Data 2
Turbo loader
Encoding:
Filename only
ROM Data 1
Autostart, loads and decrypts turbo loader
ROM Header 2
Filename only
ROM Data 2
Turbo loader
Endianess:MSbF
Threshold:0x02bc (payload/sync), 0x03b6-0x060e (lead-in)
Lead-in:4096 x 1-bit + 1 x 0-bit
Sync:0xff
Structure:Threshold:0x02bc (payload/sync), 0x03b6-0x060e (lead-in)
Lead-in:4096 x 1-bit + 1 x 0-bit
Sync:0xff
Header:No
Checksum:Yes
Checksum:Yes
Treshold:
Loader uses a special threshold for the lead-in bits.
Any pulse within the interval is counted and the loader requires there to be at least 0x7f lead-in bits.
Encryption:
The encryption of the turbo loader is a simple EOR, starting at 0x01 for the first byre.
Then increases by one for each byte and wrapping to 0x00 after 0xff.
Data:
Load starting address is hardcoded, as is the number of blocks to load.
Each block is 256 bytes, and last block should always be 256 bytes.
File #1: Start 0x0200, blocks 0x6b
File #2: Start 0x6e00, blocks 0x90
Checksum:
EOR of the sync byte, all payload bytes and the checksum byte following the last block should cancel out to 0x00.
Loader uses a special threshold for the lead-in bits.
Any pulse within the interval is counted and the loader requires there to be at least 0x7f lead-in bits.
Encryption:
The encryption of the turbo loader is a simple EOR, starting at 0x01 for the first byre.
Then increases by one for each byte and wrapping to 0x00 after 0xff.
Data:
Load starting address is hardcoded, as is the number of blocks to load.
Each block is 256 bytes, and last block should always be 256 bytes.
File #1: Start 0x0200, blocks 0x6b
File #2: Start 0x6e00, blocks 0x90
Checksum:
EOR of the sync byte, all payload bytes and the checksum byte following the last block should cancel out to 0x00.