Writing TI-59 mag cards.

[Matt Agajanian]

Hi all. From what I can gather as I’m reading the mag card section of Personal Programming, it seems to me starting with bank one progam steps are in ascending order while memory registers are in reverse.

So, if I understand the 59 memory map, if I want to write registers 0-29, I would write bank four onto a mag card side. Conversely, if I wish to record program steps 0-239, I would record bank one onto a card side.

Is this how it works? Am I correct?

Thanks

[Dave Britten]

Yup, you are correct. See page VII-1 of the manual ("Personal Programming") for a diagram, but here's the breakdown:

Bank 1: steps 0-239 or registers 99-90
Bank 2: steps 240-479 or registers 89-60
Bank 3: steps 480-719 or registers 59-30
Bank 4: steps 720-959 or registers 29-00

The default partitioning at power on has banks 1 and 2 designated as 480 program storage and banks 3 and 4 for 60 registers. Also note that a bank can contain a mix of program steps and storage registers if you've partitioned memory with something other than 0, 30, 60, or 90 registers.

One trick I like to do when writing a program card is to verify it by reading it back into bank 4 (put -4 in the display to force reading the card as bank 4). That way you can verify the card is good without replacing the program steps in the lower banks - or inadvertently blowing them away if the read/write fails! After reading the card this way, hit 2nd CMs to clear the junk data that will be in the storage registers.

[Maximilian Hohmann]

Hello!

(10-12-2022 04:49 PM)Dave Britten Wrote:  ... hit 2nd CMs to clear the junk data that will be in the storage registers.

That is not junk but program instructions transformed into numeric values! The process is reversible. If you change the memory partition between writing and reading a card, programs can be turned into numbers and vice versa.

I remember that back in my Ti59 days (1978 to 1985 or so) people came up with, and published!, clever ways to make self modifying code on the Ti59 by having their program change some stored numbers, writing them on a card and reading them back in as program statements. That can all be programmed, the user only has to slide the card into the calculator when prompted. Maybe I still have the magazine article in some box that got never opened after our last relocation (22 years ago) but I am pretty much certain that I will never find it again...

Regards
Max

[Dave Britten]

(10-12-2022 05:04 PM)Maximilian Hohmann Wrote:  Hello!

(10-12-2022 04:49 PM)Dave Britten Wrote:  ... hit 2nd CMs to clear the junk data that will be in the storage registers.

That is not junk but program instructions transformed into numeric values! The process is reversible. If you change the memory partition between writing and reading a card, programs can be turned into numbers and vice versa.

I remember that back in my Ti59 days (1978 to 1985 or so) people came up with, and published!, clever ways to make self modifying code on the Ti59 by having their program change some stored numbers, writing them on a card and reading them back in as program statements. That can all be programmed, the user only has to slide the card into the calculator when prompted. Maybe I still have the magazine article in some box that got never opened after our last relocation (22 years ago) but I am pretty much certain that I will never find it again...

Regards
Max

You are quite correct! I was mostly glossing over that fact and presuming that the data is junk to the typical user But the 59 has lots of interesting things to explore, such as the HIR registers, and the combined program/data storage that you've mentioned. (To say nothing of all the interesting tricks you can do when the printer is involved.)

I think a couple of other TIs allowed for self-modifying code in much the same way - can't remember exactly which ones though.

[Sylvain Cote]

(10-12-2022 05:04 PM)Maximilian Hohmann Wrote:  I remember that back in my Ti59 days (1978 to 1985 or so) people came up with, and published!, clever ways to make self modifying code on the Ti59 by having their program change some stored numbers, writing them on a card and reading them back in as program statements.

SR-52 self-modifying code → TI PPX v2n4