A83: 83p file format

To: <assembly-83@lists.ticalc.org>
Subject: A83: 83p file format
From: "Florent Dhordain" <jldhordain@nordnet.fr>
Date: Sat, 20 Jun 1998 23:51:13 +0200
Delivered-To: assembly-83-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-83@lists.ticalc.org

    Movax made me notice I'd made an error in the 83p file format. The word at
37-38 is 0b 00 instead of 0c 00. Sorry if someone wondered why his program
didn't work cause of that.

- Florent

                               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


Thanks to :
Sami Khawam <sKhawam@bigfoot.com> for input about general .8?? files 
(especially .83b), and for providing us (W)tran8x(32), of course !

Movax <movax@algonet.se> for telling me the variable header length was 0b 00