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#1 senior_falcon OFFLINE  

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Posted Thu Sep 21, 2017 8:09 PM

In XB there are 24 bytes from >FFE8 to >FFFF that are not used by Extended BASIC.  Why are these bytes reserved?  Is there any reason they cannot be used as a mailbox to pass information between different XB programs?


Edited by senior_falcon, Fri Sep 22, 2017 6:08 AM.


#2 RXB OFFLINE  

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Posted Fri Sep 22, 2017 3:52 AM

Many years ago I read something about >FFE8 to >FFFF being assigned to a TI memory expansion concept mentioned in the XB ROM source that I lost.

 

It did not explain anything about it or how it worked. But it did mention a DEBUGGER CARD being used to demo the use.



#3 senior_falcon OFFLINE  

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Posted Fri Sep 22, 2017 1:25 PM

It was reserved for some purpose and that makes as much sense as anything.  Load interrupt uses >FFFC and >FFFE, but that's the only use I can see in that area.



#4 acadiel OFFLINE  

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Posted Fri Sep 22, 2017 6:56 PM

Corcomp Load Interrupt Card. I had modded it a while back to remove the 5V from the sidecarts I was dumping. LOL. Power up, go into Mini Mem, give the side car 5V, and the dump the DSR and 32K space :-)

If you used it as intended, and pressed the button, it would go to >FFFC and jump to that address’ contents, I believe.

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#5 Ksarul OFFLINE  

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Posted Fri Sep 22, 2017 8:18 PM

I think the RAM Trap used that space as well. . .



#6 InsaneMultitasker ONLINE  

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Posted Fri Sep 22, 2017 11:22 PM

Millers Graphics documentation doesn't show any use for that space.  I wonder if the space below the load interrupt vector was used in an older version of XB, or for some specific future function that was never implemented.

 

I use memory from >A000 up as my mailbox space in many programs.  For example, my BBS software uses >a000->a500 (just over 1k) for various buffers and information passing.  Since upper memory usage is determined by program size plus numeric variable run-time space, it is relatively easy to ensure my program 'modules' never cross into that area.



#7 ralphb OFFLINE  

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Posted Sun Sep 24, 2017 5:58 AM

According to Thierry: "As mentionned above, the five registers of the floppy disk controller map in the memory area >FFF0-FFFF. The addresses are different for read operations than for write operations".



#8 senior_falcon OFFLINE  

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Posted Sun Sep 24, 2017 6:53 AM

According to Thierry: "As mentionned above, the five registers of the floppy disk controller map in the memory area >FFF0-FFFF. The addresses are different for read operations than for write operations".

That must be a misprint.  The assembly code examples on that page all show the registers stored at >5FF0 to >5FFF.  Which makes sense because the disk system will work without memory expansion.



#9 Lee Stewart ONLINE  

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Posted Sun Sep 24, 2017 6:57 AM

According to Thierry: "As mentionned above, the five registers of the floppy disk controller map in the memory area >FFF0-FFFF. The addresses are different for read operations than for write operations".

 

I always wondered why TI Forth (and fbForth by inheritance) stayed clear of >FFF2 – >FFFF.  The 82-byte Terminal Input Buffer (>FFA0 – >FFF1) is the highest memory used.  Perhaps this is the reason—or not (per Harry's post above).

 

...lee

 

[Edits in this color.]



#10 Lee Stewart ONLINE  

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Posted Sun Sep 24, 2017 7:06 AM

That must be a misprint.  The assembly code examples on that page all show the registers stored at >5FF0 to >5FFF.  Which makes sense because the disk system will work without memory expansion.

 

That makes even more sense in light of the table immediately following that statement.  When I first read it, that disparity puzzled me.

 

...lee



#11 senior_falcon OFFLINE  

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Posted Sun Sep 24, 2017 10:12 AM

 

That makes even more sense in light of the table immediately following that statement.  When I first read it, that disparity puzzled me.

 

...lee

Plus, if you do a search for >5FF it occurs 41 times on that page with instructions like:

           MOVB @>5FF0,R6   Read FDC status register

 

RDY   MOVB R0,@>5FF8   Send command to FDC command register

 

etc.



#12 Airshack OFFLINE  

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Posted Sun Sep 24, 2017 7:35 PM

Millers Graphics documentation doesn't show any use for that space. 


Which Millers Graphics docs? Link?


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#13 InsaneMultitasker ONLINE  

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Posted Sun Sep 24, 2017 8:37 PM

Which Millers Graphics docs? Link?


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I thought I typed the reference.  Ah well.  It was Millers Graphics The Smart Programmer monthly newsletter. I was reading the real, printed document.

 

Edit:  Just got back home; the memory layout I looked at is in the March 1984 issue. 


Edited by InsaneMultitasker, Sun Sep 24, 2017 10:06 PM.


#14 Lee Stewart ONLINE  

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Posted Sun Sep 24, 2017 9:53 PM

Which Millers Graphics docs? Link?

 

I thought I typed the reference.  Ah well.  It was Millers Graphics The Smart Programmer monthly newsletter. I was reading the real, printed document.

 

...on the WHTech site under ..\magazines\smartprogrammer.

 

...lee



#15 RXB OFFLINE  

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Posted Mon Sep 25, 2017 8:28 AM

 

I always wondered why TI Forth (and fbForth by inheritance) stayed clear of >FFF2 – >FFFF.  The 82-byte Terminal Input Buffer (>FFA0 – >FFF1) is the highest memory used.  Perhaps this is the reason—or not (per Harry's post above).

 

...lee

 

[Edits in this color.]

Hmm I told you guys it was for a future expansion paged memory created by TI, but never made it past set up stage.

 

It was mentioned on the side notes handwritten from my old XB ROM source I got from TI.


Edited by RXB, Mon Sep 25, 2017 8:30 AM.


#16 Airshack OFFLINE  

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Posted Tue Sep 26, 2017 10:45 AM

It was mentioned on the side notes handwritten from my old XB ROM source I got from TI.


Hey Rich, Are these handwritten notes scanned and archived anywhere? I can't remember reading this anywhere else? -j


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#17 RXB OFFLINE  

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Posted Tue Sep 26, 2017 10:45 PM

Hey Rich, Are these handwritten notes scanned and archived anywhere? I can't remember reading this anywhere else? -j


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I hand typed in all 5 inches of pages of the source including the handwritten notes and uploaded them to GENIE and the KEEP and other BBS.

 

I also mailed copies to numerous people after they asked for them on DISKs. 

 

My computer SCSI Hard drive crashed and I lost all copies but to make matter worse I loaned the original hard copy to a buddy that lost them in a Portland Oregon flood.

 

So no unless someone has them from these copies I made we no longer have this source.


Edited by RXB, Wed Sep 27, 2017 8:27 PM.


#18 senior_falcon OFFLINE  

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Posted Wed Sep 27, 2017 8:12 AM

That's discouraging!  Do you still have the original hard drive?  I had a hard drive crash and lost some pictures.  I was lucky-it was the circuit board on the drive that failed.  I got an identical drive on ebay and swapped out the board and was able to retrieve the pictures. 



#19 Airshack OFFLINE  

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Posted Wed Sep 27, 2017 3:57 PM

Wondering if those files are sitting around on some internet archive somewhere?


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#20 RXB OFFLINE  

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Posted Wed Sep 27, 2017 8:30 PM

That's discouraging!  Do you still have the original hard drive?  I had a hard drive crash and lost some pictures.  I was lucky-it was the circuit board on the drive that failed.  I got an identical drive on ebay and swapped out the board and was able to retrieve the pictures. 

Sorry no I have extensive software on the Mac and Windows side to recover drive data and it was totally gone or corrupted beyond recovery.



#21 RXB OFFLINE  

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Posted Wed Sep 27, 2017 8:31 PM

Wondering if those files are sitting around on some internet archive somewhere?


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I have repeatedly asked the community to search archives for it including WHT FTP that had a copy uploaded to it.....no replies.



#22 sparkdrummer OFFLINE  

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Posted Wed Sep 27, 2017 8:54 PM

Any idea of the file names Rich?

#23 RXB OFFLINE  

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Posted Thu Sep 28, 2017 3:01 AM

Yea all of them named XBROMSRC1 and 2 or XBROMS1 and 2.



#24 sparkdrummer OFFLINE  

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Posted Thu Sep 28, 2017 7:04 AM

Well, I looked in all my stuff for those files - I came up empty.

 

I came across some files that say IMYXB3 text and dsks - which are in a folder entitled RXB v2001 source - I don't suppose these are what you're looking for. 



#25 RXB OFFLINE  

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Posted Thu Sep 28, 2017 8:24 AM

Well, I looked in all my stuff for those files - I came up empty.

 

I came across some files that say IMYXB3 text and dsks - which are in a folder entitled RXB v2001 source - I don't suppose these are what you're looking for. 

Sorry no this was done just before I released RXB 2001, at the time I think it was RXB version 5.55 released.


Edited by RXB, Thu Sep 28, 2017 8:25 AM.





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