Re: A83: 83P format verification
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Re: A83: 83P format verification
This on a couple of different sites
83P file format
=================
by Florent Dhordain <flo.dh@usa.net>
Offset(hexa)
00- 07 "**TI83**"
08- 0B 0x1A, 0x0A, 0x00 (for the85-86 : 0C instead of 0A)
0C- 34 Comment
35- 36 file length - $39 = Size of all data in the .8?? file, from
byte $37
to last byte before the checksum
; Var header part :
37- 38 variableheader length = 0B 00
39- 41 Variable Header
|--- 39-3A Length of data (word)
|--- 3B program type : 5 (6 for protected)
|--- 3C-43 program name (0-filled)
; Data part :
44-45 Length of data
46-47 Length of program
48-xxx Program data
xxx checksum (word)
Notes :
* All the length are one word, with Least Significant Byte first
* Length of program = the length of all the program data (incredible !)
* Length of data = length of program + 2 (cause it is length of the
datablock,
which contains program length(2 bytes) + program data)
* Word at 35-36 = length of program + $11 (17)
* The checksum is one word, the sum of all the bytes from byte 37 to
the last byte before the checksum, modulo 2^16-1 to fit in one word
AtmaZ@aol.com wrote:
>
> OK, I think I got an idea of how the 83P file is stored, but I need somebody
> else to look on it.
>
> Right now I'm going to assume than every character in the ANSI/ASCII set is
> represented by one byte. (I think...somebody want to proof this?)
>
> Bytes 1-8: Always "**TI83**".
> Bytes 9-10: In DIAMONDS.83P (my example) they are ASCII values 26 and 10,
> respectively. I'm not too sure what they represent; I think they can be
> ignored.
> Bytes 11-50: Comment field. I think.
> Bytes 51-60: ??? In my editor, they were ASCII values 46 (".") , 95 ("_"), 85
> ("U"), 169, 8, 11, 0, 154, 8, and 6. I have no idea if this represents
> anything significant.
> Bytes 61-68: Name of the program.
> Bytes 69-end: Program data.
>
> Actually, all I'm trying to get to is the program data, but I need to make
> sure of this so I don't access the wrong stuff.
>
> Thanks in advance,
>
> --David
--
Scott "_Wrath_" Dial
homosapian@geocities.com
ICQ#3608935
http://www.geocities.com/~homosapian/
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