Sill M100 BASIC fun...

[desiv]

OK, I have my 8K Model 100.  It has a key that is problematic (it works with a rubber band around it), 1 horizontal pixel line that is really lite), and only the 8k, so a while ago, I thought I might look for a parts 100....

Ended up getting a 24k M100 in better shape for a great price.

 

I replaced the batteries on both.  There was some minor battery leakage on the 24k one, but it appeared cosmetic.

While troubleshooting some serial issues (that I think are related to my cheapo USB serial adapter), I decide to look for a memory test program.

I found one on Club100 and downloaded it and transferred it over (600 baud, waiting for that new USB/serial adapter).

Memory test failed.

Tried it on my other M100.

Memory test failed.

Hmmm...

So, since this is BASIC (there is an ML part in data statements in the bottom, but mostly BASIC) I decided to take a look.

My initial theory is that the test program was written for a 32k machine only.

I find this line:

250 FORH=32*1024TO64*1024STEP256
I didn't understand the memory map, but that 32 made we wonder.

So I dug into the memory map.

Looks like the M100 has 32k of ROM and the next 32k is RAM, but it is mapped where the standard 8K is mapped at the top.  And added RAM goes below.  So I learned something about my M100.

I decided to test it.

Changed that 32 to 40 (Since added RAM is mapped high, 32 means the block is full.  My 24k model has 8k less, so this program starts at 8k above what a 32k machine would start at).  Ran it.

Memory test passed!!!

Yay, but since this is basic, I just couldn't leave it like that.

So, I changed:

60 PRINT"Continue?  <Y>es or <N>o

..to

60 PRINT"Cont? <N>, 1-8k, 2-16k, 3-24k, 4-32k"

 

and then

90 IFA$="Y"ORA$="y"THEN120

...to

90 IFA$="1"ORA$="2"ORA$="3"ORA$="4"THEN120

 

and finally

250 FORH=32*1024TO64*1024STEP256

...to

250 FORH=(64-VAL(A$)*8)*1024TO64*1024STEP256

 

So now I can type 1-4 to test from 8k up to 32k!

 

Did I need to do that?  No...

Will I use this program a lot?  No...

Was this kind of silly?  Yes...

 

And fun...

I do miss BASIC..

 

Oh, forgot.

I also changed:

130 PRINT"Starting RAM test

...to

130 PRINT"Starting at: ", (64-(VAL(A$)*8))*1024

 

 

Edited September 6, 2020 by desiv