Re: Disk controller

[Don Bruder <dakidd@sonic.net>]

In article <qhhda5zfhk.fsf@ruckus.brouhaha.com>,
 Eric Smith <eric@brouhaha.com> wrote:

> simcop2387 <simcop2387@gmail.com> writes:
> > Ok i've been playing around trying to get the disk controller to work
> [...]
> > what i don't know yet is why when it reaches the end of the rom it jumps
> > to $0801 (which ends up filled with garbage it would appear when looking
> > at the contents of the memory thanks to the apple monitor).
> 
> The disk boot loads track zero sector zero into memory from $0800 through
> $08FF, and jumps to $0801.
> 
> So the jump to $0801 is correct, provided that it's read a sector first.


Exactly correct on all counts. Give that man a seeeee-gar *AND* a 
Cupie-doll! :) 

For fifty worthless bonus points, ring in and tell me why the boot 
sequence doesn't JMP $0800 instead of $0801? (aside from the obvious 
"The code isn't ORGed to $0800")

ROT13 for the answer:
"OBBG1", gur pbqr ybnqrq gb $0800-$08SS ol OBBG0 (gur EBZ ba gur pneq) 
pbagnvaf n ybbc gung pnyyf gur pbqr ba gur pneq gb ernq zber frpgbef 
vagb ENZ. $0800 vf gur pbhagre sbe guvf ybbc, gryyvat gur pbqr ubj znal 
frpgbef ner gb or ybnqrq. Guhf, gur WZC $0801.

-- 
Don Bruder - dakidd@sonic.net - If your "From:" address isn't on my whitelist,
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