Omnimaga
Calculator Community => TI Calculators => ASM => Topic started by: DrDnar on July 14, 2011, 05:11:29 am
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Remember how in IM 2, the high byte comes from the I register and the low byte of the address for your ISR is random? That may have been true for the TI-83+, but I don't think it's true for the TI-83+SE and TI-84+(SE). A while ago, I did some tests on my TI-84+SE that suggested that in IM 2, the only vector that ever gets used is the FF one. Now, once again, I have written a slightly more advanced tester, based on MicrOS, to keep track of what vectors are issued. Attached is a program for this and its source. Be aware, this program erases all of your RAM. Run the program, and you just get a basic hex editor, starting at address 6200. Address 6200 is the start of a table keeping track of how often a particular IM 2 vector is used. Each entry is two-bytes, so to check how often 20h was used, go to 6240h. The only vector I have ever seen is FF (63FE). Does anybody else with TI-83+SE or TI-84+(SE) ever see a non-zero value in the 6200h to 63FDh range?
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Yes, on my 84+SE S-0404 with ViewScreen port. The vector seems to be random, writing to various bytes between 6200h and 6400h. On my 84+BE S-0306F it appears "normal" (nothing but 63FEh written to). Could this have to do with the ASIC version or port 15 at all?
EDIT: 100th post!
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Yeah, DrDnar, I made a test like this a long time ago, and I can say that mine is random. It favors some addresses, but in the end, it's unpredictable.
I just ran mine and I get hits in random blobs about every 30 bytes.
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It could indeed be very related to the ASIC revision. Perhaps only the ones that read 45 from port 15 are predictable? Which would make this kind of useless.
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Hmm... Sound interesting. It would be nice if we didn't have to fill that huge space with all the same number. :/