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** MALFUNCTION MALFUNCTION **

TI BASIC TRICK TOKENS REMARK STATEMENT

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#26 BuckoBrand OFFLINE  

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Posted Sun Feb 3, 2019 8:23 AM

The REM w/CTRL characters... or the Pac-Man trick? ;-)

Pac-Man



#27 HOME AUTOMATION ONLINE  

HOME AUTOMATION

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Posted Sun Feb 3, 2019 11:14 AM

I had trouble with my last post... I meant to say ...they're both good!

 

But you are right...  The Pac-Man trick gets better mileage.

:D :D :D



#28 ChildOfCv OFFLINE  

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Posted Sun Feb 3, 2019 12:41 PM

Could this be something intended to work like the keystrokes on a timex1000

or maybe something interacting from modem control codes?

 

Most likely it's because the internal representation of BASIC programs is single bytes representing reserved words.  So if it lets you enter bytes directly when using REM, and the listing doesn't have special logic for the REM case, it will decode the line as usual which means tossing reserved words at you for those particular bytes.



#29 HOME AUTOMATION ONLINE  

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Posted Sun Feb 3, 2019 1:12 PM

 

Most likely it's because the internal representation of BASIC programs is single bytes representing reserved words.  So if it lets you enter bytes directly when using REM, and the listing doesn't have special logic for the REM case, it will decode the line as usual which means tossing reserved words at you for those particular bytes.

Since the time I started this topic, I have had a look at the code For REM in the GROM 0 disassembled GPL listing. I have reached similar conclusions... :cool:

 

GROM 0 Listing from, TI INTERN by Heiner Martin.

 

http://www.99er.net/...act=view&id=102


Edited by HOME AUTOMATION, Sun Feb 3, 2019 1:15 PM.


#30 ChildOfCv OFFLINE  

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Posted Sun Feb 3, 2019 2:47 PM

The dangers of reviving old posts :D



#31 InsaneMultitasker OFFLINE  

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Posted Sun Feb 3, 2019 4:17 PM

First there is a delay.  Then you observe the pattern table shifting down 1 pixel row. All the visible chars drop one pixel lower, but not all at the same time. It's slow enough for you to have a  thought that your program is gone and memory is being trashed.

Then the screen fills with sprites and gibberish, and the really bad stuff begins.

 

... the screen begins to "tear". There are seconds of darkness, then a flash of bright white, followed by pulses of distorted video between which fragments of your program are briefly visible. There is an audible whine from the television set as the video signal pushes it beyond its comfort envelope.
<snip>

However, after a time, the madness ceases. The blackness is still. There is a softly blinking spot. The cursor is back! You press enter; nothing improves. You make a syntax error, and the screen is somewhat restored.

 

>

Your vivid description sounds like a great pre-amble to am Infocom nightmare. 



#32 RXB OFFLINE  

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Posted Sun Feb 3, 2019 8:11 PM

As much as I appreciate any participation in my topic. Perhaps I was vague about my main interests here. I am still hoping to elicit some interest in the TI BASIC anomaly that occurs when editing a program line longer than the screen table. Why these reserved words are associated with CTRL and FCTN characters in the first place? Why do they operate in this manor in a REMARK statement?

All commands in TI BASIC and XB are tokenized to save program space and speed.

Example instead of GPL looking for the full word typed in like SEQUENTIAL it just looks for >F6 which using a key press can put the Tokenized version into the editor mode.

(What you are doing is by passing the conversion and it sees the token without needing the search for the token.)

 

It would take longer to find SEQUENTIAL then >F6 thus why Tokens are used.


Edited by RXB, Sun Feb 3, 2019 8:13 PM.


#33 BuckoBrand OFFLINE  

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Posted Sun Feb 10, 2019 11:15 AM

Nice!







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