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Full Reverse Engineering of the TI-84 Plus Operating System

129 pointsby sirabenyesterday at 5:41 PM20 commentsview on HN

Comments

asveikauyesterday at 8:36 PM

> TI-BASIC programs are stored as tokens, not text: every command, function, and variable is a token of 1 or 2 bytes. The OS detokenizes (token→display string) to show a program and tokenizes (keypress/text→token) on entry; the parser walks tokens to execute.

From my memory of using a TI-83 in the late 90s, I would not be surprised if the keypad UI injects tokens directly based on your keypress, rather than "tokenizing the text". I seem to recall, for example, you could not position the cursor in the middle of a BASIC token, and if you managed to type out the tokens it would not work; you needed to find the right menu item to inject the correct token.

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analogpixelyesterday at 6:06 PM

I couldn't tell, is a person doing this? or was this an LLM dissecting it?

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tadfisheryesterday at 6:20 PM

I love that this project produced so much info, and also I'm disappointed with the prose. You probably didn't mean to explain the typographic nuances of em vs. en-dashes to the reader: https://siraben.github.io/ti84p-re/conventions.html#typograp...

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thwgrwyesterday at 8:51 PM

I am sure you did a lot of hardwork here. But with all the LLM smell in the text, my mind zoned out after few lines. I'd rather read a flawed but human written text than a perfect one written or co-written with an LLM.