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Re: And the trace begins... Pick-A-Dilly Pair
On Thursday, October 25, 2012 12:18:06 PM UTC-5, Steve Nickolas wrote:
> I'm trying to understand the various disassemblies and such and figure out
>
> how the data translates...
>
>
>
> The table in HELLO.LST contains values that, in order, go into
>
> B7EC, B7ED, B7F0, B7F1
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> and the last number into a counter which is decremented. But some of
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> these values don't appear to make sense with my current understanding.
>
>
>
> 1. "Sector" values that exceed 16
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> 2. Addresses in the ROM space, when analysis shows the ROM is never used
>
>
>
> So I'm parsing the table wrong...
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>
>
> -uso.
Here ya go.
0E51- 13 ???
0E52- 0E D0 02 ASL $02D0
0E55- 01 14 ORA ($14,X)
0E57- 0E 01 0F ASL $0F01
0E5A- 11 16 ORA ($16),Y
0E5C- 0E FC 5F ASL $5FFC
0E5F- 0E 17 0E ASL $0E17
0E62- FC ???
0E63- 8F ???
0E64- 06 18 ASL $18
0E66- 0E FC 6F ASL $6FFC
0E69- 20 00 1B JSR $1B00
0E6C- 0E FC 3F ASL $3FFC
0E6F- 09 1C ORA #$1C
0E71- 0E FC 4E ASL $4EFC
0E74- 0E 1D 0E ASL $0E1D
0E77- FC ???
0E78- 60 RTS
0E79- 2F ???
0E7A- 00 BRK
is:
(read as track, sector, starting buffer address, sector count to read)
First batch:
$13 $0E; $02D0; #$1
$14 $0E; $0F01; #$11
$16 $0E; $5FFC; #$0E
$17 $0E; $8FFC; #$06
$18 $0E; $6FFC; #$20
then there's a #$00 at $E6A signaling the end
Second batch:
$1B $0E; $3FFC; #$09
$1C $0E; $4EFC; #$0E
$1D $0E; $60FC; #$2F
then another #$00 at $E7A to signal the end
The sectors are read in descending order; the tracks are read in ascending order.
The buffer addresses are starting addresses, and are incremented (hi byte).
Since the starting address mostly start at the $xxFC offset, that suggests to me that these are probably binary DOS files, and the normal four-byte header is loaded into $xxFC so that the real data is able to then land starting at the next page boundary.
]HR