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Geneve MDOS New Call


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#1 BeeryMiller OFFLINE  

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Posted Sat Nov 24, 2018 8:40 PM

Tim,

 

Got a few questions. 

 

1. What did Tony's Geneve 1.00 eprom code do with respect to the SCSI card? Will 0.98 code (not sure if that is what I have), locate LOAD/SYS on the DSK1 subdirectory of the SCSI controller and load MDOS?

 

2.  What kind of space do you have left in the CLI memory range for new code?  I suspect very little.  Can it handle a new command ("TI") and parse with a command line option with a call to a UTIL library routine?

 

3.  What kind of space do you have in the memory mapped range that holds the UTIL library?

 

What I am looking at doing, is replacing the Swan/RSBug code with the EXEC code.

 

Then, from the command prompt, one would type "TI MYWORD" and it would parse the option, and filepath, then a subsequent call to a new library routine would move from pages >F0 and >F1 in the Eprom the EXEC code to two available ram pages.  Might not need the parse code in the CLI as I would have to follow if the code moved from the Eprom can pick it up.

 

I've not verified, but I am assuming the EXEC code can not be run from ROM on the Eprom.  I have around 13,900 bytes I can use that could also be loaded with something other EXEC, however, that is the one program I think most people would use.

 

Beery

 

 

 

 

 



#2 atrax27407 OFFLINE  

atrax27407

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Posted Sat Nov 24, 2018 9:22 PM

According to the notes that I got from Tony when he sent me the EPROM .bin file, it adds a menu and allows for loading from a SCSI device.



#3 InsaneMultitasker OFFLINE  

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Posted Sun Nov 25, 2018 1:52 AM

Space is at quite a premium in the CLI.

 

I would suggest considering an alternative:  determine what would be required to modify the MDOS task loader to detect the TI program image header and if found launch the EXEC code. The routine would need to disable itself if EXEC wasn't found in the EPROM or invoke EXEC as if the user typed it manually.  I would not be opposed to allowing an 8k page of RAM to be reserved for EXEC at OS startup, like a TSR (and similar to Tony's GPL routine) in place of the EPROM.   Keep in mind that some of the memory management routines are also in premium space. 

 

geneve EPROM 0.98 boots only from the three standard floppy controllers, the Myarc HFDc, and the Horizon RAMdisk.



#4 BeeryMiller OFFLINE  

BeeryMiller

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Posted Sun Nov 25, 2018 2:06 PM

OK, let me flesh this out with you Tim to see if it is possible.  My first thought is to try and not use any additional RAM further limiting available memory after booting.

 

Let's say we add a new XOP in the task header pages and page >00 if it detects a specific Eprom version.  The new  XOP maps in code from the Eprom pages of >F0 and >F1 when called.  The Util Library Load Task opcode is opcode 9.  We have "dummy" opcodes from >00 to >08 with >09 "identical" in the new XOP as the Util equivalent of XOP opcode >09 except looking for a TI-99/4A program image file.  The thought here is if one XOP Library call fails, then test against the other XOP library before finally aborting.  Maybe just a couple of instructions in the CLI.  The big question here is how many bytes are available in the CLI that can be used.  I know you said premium.  One time, I thought I remember there may have been 20(?) bytes.  If we are in single digits of available bytes, there may not be the space to clear the error code and test against the new opcode.

 

I already have the basis of a TSR written so testing with the actual eprom modification can come later.  The big question is identifying where access can be coded without consuming additional RAM memory pages for MDOS.

 

Beery



#5 InsaneMultitasker OFFLINE  

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Posted Mon Nov 26, 2018 10:54 PM

Sorry, I need a little more detail and 'fleshing out', specifically what you think would happen with memory pages and workspaces.  I think I know where you are heading but can't give you an answer without a little more discussion.






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