Thread: BS1 intro
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Old 09 January 2013, 22:38   #16
mark_k
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Join Date: Aug 2004
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The funny thing is, (as far as I can tell) the code which trackloads another 1KB of data after the intro is completely broken. It's lucky the machine doesn't crash.

It loads 1KB of data from offset $76400 to the address pointed to by A4. A4 contains whatever value was in there when the bootblock code was originally called.

It then loads the bootblock (i.e. 1KB from offset 0) to address $FC00 but doesn't do anything with it. Then it decodes (NOTs) the code it loaded to (A4) and jumps to offset 12.

The data at offset $76400 is probably supposed to be the disk's original bootblock, so the intro is supposed to chain-load that. But at least on this disk, it isn't. The data at offset $76400 looks to be a fragment of demo code. Maybe there's an uncorrupted/unmodified version of this disk somewhere???
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