|
# The following KSY file shows the binary structure of 8XP files. |
|
# These files are programs used on Texas TI-83 Plus and TI-84 Plus |
|
# calculators. |
|
meta: |
|
id: ti_8xp_file_format_template |
|
file-extension: 8XP File Format Template |
|
# Wherever two-byte integers are used, they are in LITTLE ENDIAN format |
|
# meaning that the least-significant byte comes first |
|
endian: le |
|
|
|
# Here is the general structure of the file |
|
# Each component is broken down further in the "types" section below. |
|
seq: |
|
|
|
# Header is 55 bytes |
|
- id: header |
|
type: header |
|
size: 55 |
|
doc: The header is always 55 bytes long |
|
|
|
# Meta data is 19 bytes |
|
- id: meta_data |
|
type: meta_data |
|
size: 19 |
|
doc: The meta_data section is always 19 bytes long |
|
|
|
# Body is variable length (length is specified in the meta data above) |
|
- id: body |
|
type: program_body |
|
size: meta_data.body_length |
|
doc: | |
|
The length of the body is variable, and the number of |
|
bytes is specified inside meta_data.body_length |
|
|
|
# Checksum is always 2 bytes, at the very end of file |
|
- id: checksum |
|
type: u2 # Two-byte, unsigned integer |
|
doc: | |
|
All programs end with a 2 byte checksum. |
|
This is calculated by summing all the bytes in the meta_data and |
|
body sections (from byte 56 to the end, excluding checksum itself), |
|
and then taking the lower 16bits (2 bytes) of the answer, |
|
in little endian form (which I think is the first two bytes of |
|
the total). |
|
|
|
types: |
|
|
|
# Here's a breakdown of what the 55 byte header contains: |
|
header: |
|
seq: |
|
|
|
- id: signature |
|
# contents: "**TI83F*" |
|
type: str |
|
size: 8 |
|
# type: s8 |
|
encoding: ASCII |
|
doc: Signature is usually these 8 chars: **TI83F* |
|
|
|
- id: signature_part_2 |
|
contents: [0x1A, 0x0A] # two bytes, always with these values |
|
doc: The signature also generally includes these 2 bytes |
|
|
|
- id: mystery_byte |
|
type: u1 # single byte |
|
doc: | |
|
Either 0x00 or 0x0A? I've noticed that most TI-BASIC |
|
apps created with TI-Connect CE have this as 0x0A, |
|
while assembly apps compiled with Brass have it as |
|
0x00. Not sure if it makes any practical difference? |
|
To be confirmed. |
|
|
|
- id: comment |
|
size: 42 |
|
type: str # string that is always 42 characters |
|
encoding: ASCII |
|
doc: | |
|
This can be anything, but is typically the version number of the |
|
app that compiled the 8XP file such as |
|
"Created by TI Connect CE 5.6.3.2278" |
|
The remaining unused characters are filled with 0x00. |
|
|
|
- id: meta_and_body_length |
|
type: u2 # two bytes, unsigned integer, little endian |
|
doc: | |
|
Number of bytes from here on, excluding the checksum |
|
(the final 2 bytes of file). |
|
This number should be 57 (39h) bytes less than the total file size. |
|
|
|
# Here's a breakdown of what the 19 byte meta data section contains: |
|
meta_data: |
|
seq: |
|
|
|
- id: flag |
|
type: u1 # single byte |
|
doc: | |
|
This appears to be some kind of flag/switch, where it's |
|
either 0x0B or 0x0D (0x0D on almost all apps I've inspected). |
|
Also 0x0D on groups. |
|
Not yet sure of the full meaning. |
|
|
|
- id: unknown |
|
type: u1 # single byte |
|
doc: | |
|
This appears to be 0x00 in most apps I've come across. |
|
Unsure of purpose. |
|
|
|
- id: body_and_checksum_length |
|
type: u2 # two bytes, unsigned integer, little endian |
|
doc: Length of the body/code section and the 2 byte checksum, in bytes |
|
|
|
- id: file_type |
|
type: u1 # single byte |
|
enum: file_types # see file_types list at end of this spec |
|
doc: | |
|
05 for normal programs |
|
06 for edit-locked ones |
|
23 (0x17) for groups |
|
Almost all assembly programs have this as 06, presumably |
|
because you cannot easily edit these on a calculator. |
|
|
|
- id: program_name |
|
type: str # string that is always 8 characters |
|
size: 8 |
|
encoding: ASCII |
|
doc: Maximum 8 chars. Unused characters are filled with 0x00. |
|
|
|
- id: version |
|
type: u1 # single byte |
|
doc: | |
|
Not sure what this actually does. |
|
Appears to vary randomly across different apps, despite |
|
them all being created with TI-Connect CE software. |
|
I have seen: |
|
0x00 |
|
0x04 |
|
0x05 |
|
0x06 |
|
...and 0x0B, however anything above 06 seems to cause an |
|
error in WabbitEmu emulator. |
|
Have seen it mentioned that it could be a version number, |
|
perhaps the version of TI-Basic or the version of the TI-OS |
|
needed to run the program (since some tokens/commands were |
|
introduced later). |
|
Apparently this field is present if the |
|
"flag" (byte 55, 0x37) == $0D. |
|
|
|
- id: is_archived |
|
type: u1 # single byte |
|
enum: archived |
|
doc: 0x00 for normal apps, 0x80 for archived, apparently? |
|
|
|
- id: body_and_checksum_length_2 |
|
type: u2 # two bytes, unsigned integer, little endian |
|
doc: | |
|
A redundant duplicate of the field above, containing the |
|
length of the body/code section and the 2 byte checksum, in bytes. |
|
Not sure why it is repeated again. |
|
|
|
- id: body_length |
|
type: u2 # two bytes, unsigned integer, little endian |
|
doc: | |
|
The length of the body *without* the checksum. |
|
It should be 2 bytes less than body_and_checksum_length. |
|
This is again a redundant measurement. Not sure |
|
which of the above is actually used on the calc. |
|
|
|
# The program body is a series of lines separated by the character |
|
# 0x3F. |
|
# |
|
# Note: if the first two bytes of the program body are 0xBB6D |
|
# then the program is an "assembly" program, not TI-BASIC |
|
# and it needs to be executed on the calc with Asm(prgmXXXX) |
|
# |
|
# I haven't implemented detection of individual tokens, as the list |
|
# is quite large. Lines are parsed, but not each token. |
|
program_body: |
|
seq: |
|
- id: lines |
|
type: str |
|
repeat: eos # continue reading line by line until we reach end of the program_body, based on its known length |
|
encoding: ASCII |
|
terminator: 0x3F # question mark character is used to end lines |
|
eos-error: false # the final line has no terminator, so we need to set this to false |
|
|
|
# Here we store some of the magic flags as used above. |
|
# Have not tested this template with all of the following types of files. |
|
# Would be good to do that. ;-) |
|
enums: |
|
file_types: |
|
0x05: program |
|
0x06: edit_locked_prgm |
|
0x17: group |
|
0x24: flash_application |
|
program_flag: |
|
0xBB6C: uncompiled_asm |
|
0xBB6D: compiled_asm |
|
archived: |
|
0x00: not_archived |
|
0x80: archived |
