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59 lines
2.4 KiB
Plaintext
59 lines
2.4 KiB
Plaintext
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*** C128 Auto-boot sector layout
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*** Document revision: 1.1
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*** Last updated: March 11, 2004
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*** Compiler/Editor: Peter Schepers
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*** Contributors/sources: unknown
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The C128 has the ability to auto-boot a floppy disk that is in the drive
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when the system is powered up, but only if track 1 sector 0 contains a
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specific signature. Below is a dump of an auto-boot sector with its
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signature.
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00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ASCII
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----------------------------------------------- ----------------
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0000: 43 42 4D 00 0C 00 02 00 00 A5 D7 C9 80 F0 03 20 CBMúúúúúú¥×É€ðúú
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0010: 5F FF A9 05 8D 06 D5 A9 4E 8D 00 FF 4C 00 0C 00 _ú©ú<C2A9>úÕ©N<C2A9>úúLúúú
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0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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0030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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0040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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0050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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0060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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0070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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0080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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0090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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00A0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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00B0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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00C0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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00D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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00E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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00F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 úúúúúúúúúúúúúúúú
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Bytes 00-02: Auto-boot signature 'CBM'
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03-04: ???
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05-06: ???
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07-08: ???
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09-1E: Boot code
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1F-FF: ???
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Below is a disassembly of the machine code contained from 09-1E.
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org = $0c00
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lda $d7
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cmp #$80
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beq skip1
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jsr $ff5f
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skip1 lda #$05
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sta $d506
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lda #$4e
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sta $ff00
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jmp $0c00
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.end
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The only document I have found which attempts to explain the layout of
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the C128 boot sector doesn't fit at all for the above sector layout. I am
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therefore not yet sure of all the details in the above sector. Anyone who
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has more info can contact me so I can update this document.
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