Help with .8xp file format

๐ŸŽ™๏ธ tryashtar ยท 2 points ยท Posted at 05:01:15 on September 11, 2016 ยท (Permalink)

Hello! I am trying to make a TI-Basic Editor in C# and found a very helpful website describing the format by which everything is saved.

http://merthsoft.com/linkguide/ti83+/fformat.html[1]

But I'm not sure I entirely understand everything. For example, this line here:

3-byte further signature. These three bytes always contain {1Ah, 0Ah, 00h} = {26, 10, 0}

I'm not sure what three bytes I'm supposed to save. The website has several spots where it mentions 0h or 1Ah and I have no idea what byte I'm actually supposed to save.

I assumed that, in the above example, it wanted the bytes with values 20, 10, and 0, but I'm not sure if that's correct. It seems strange seeing as the character 0 is the null terminator.

Anyway, I don't know if this is a good place to ask this question, but I couldn't find any information elsewhere. Basically, what bytes is it looking for, and, if I'm supposed to save a byte with a certain value, do I just write the character with that byte value to the file? Thanks.

[1]

File Formats

empire539 ยท 3 points ยท Posted at 05:47:06 on September 11, 2016 ยท (Permalink)

If you don't get any good answers here, I'd recommend asking over at Omnimaga or Cemetech, which have a lot more people who deal with this stuff.

adriweb ยท 3 points ยท Posted at 09:05:25 on September 11, 2016 ยท (Permalink)*

Those bytes are constant, basically, so just read/write them as-is.

For instance, see this code (C++) or this more readable one (PHP), or even this one (C#), they deal with that.

๐ŸŽ™๏ธ tryashtar ยท 2 points ยท Posted at 21:35:52 on September 12, 2016 ยท (Permalink)

Thank you for those code links, they were quite helpful.

Though I still don't understand exactly what is meant by 1Ah and so on. What number does that represent?

adriweb ยท 2 points ยท Posted at 21:52:55 on September 12, 2016 ยท (Permalink)

I'm not sure what you're asking - 1Ah is 0x1A, which is hexadecimal for 26 (decimal). As for what it means in the context of the TI variable format, I don't think it's known, it's just a constant that's been there forever.

๐ŸŽ™๏ธ tryashtar ยท 2 points ยท Posted at 21:58:31 on September 12, 2016 ยท (Permalink)

Ohh, the H is for "hexadecimal." Hahahaha, thanks, I was so confused thinking, "H is farther down the alphabet than F -- why is it in this number?"