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NASM question/8086 ROM monitor

RichCini

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Joined
Aug 7, 2005
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Long Island, NY
All –

One of my side S-100 projects is getting SCP-DOS running on a minimalist system. More of an intellectual exercise than having any true purpose. It’s very simple – a 12-slot backplane with a RAM22 board (128k), SCP300 8086 board and the CompuPro System Support board (I really want the Seattle board, though). I also have a Cromemco FDC16 controller which I have tested and works (the FDC16 was supported by SCPDOS 1.25 as a compiler option).

I have a simple monitor called muMon88 (http://www.nj7p.org/Computers/Software/Mon.html) which appears to be similar to MON88 from Tom Cantrell as published in BYTE Magazine in November 1980.

My issue I think relates to the quirky syntax of NASM in placing things in memory exactly where you want them. The code is in ROM @ F:F800 but there is a section for uninitialized data that is supposed to be located in low RAM -- I located it @ 0:500 using the “absolute 00500H” compiler directive. I do have SECTION directives for code and bss. The LIST file seems to show everything in the right place but certain functions of the monitor don’t work as expected - there is a "register save" area which always shows 0xFF when read (for example).

Does anyone on-list have enough experience with NASM that maybe could look at the code and see if I have it setup correctly? As an alternative, if someone has a 2k-sized 8086 ROM monitor that they use and would be willing to share, maybe I’d try that as an alternative. I don't particularly like the syntax of the commands in this monitor anyway, so I'm not wed to it.

Thanks!
 
Sorry for bumping an old thread, but PM seems broken....

Rich
Have you made any headway on this?
I have built a 8088 SBC and I'm looking for a small "debug" monitor.
Google search shows almost nothing that isn't "Micro 8088" related.

joe
 
I've seen the SCP monitor but only in PDF form. I didn't want to type it in. (or try to OCR)
Thanks for the link to the source.

joe
 
I've seen the SCP monitor but only in PDF form. I didn't want to type it in. (or try to OCR)
Thanks for the link to the source.
joe

There are several versions available in that directory along with a couple of binaries (presumably dump(s) of the ROM from an SCP support card) too.
 
There are several versions available in that directory along with a couple of binaries (presumably dump(s) of the ROM from an SCP support card) too.

Those came from my own system. There is more than one version of the SCP monitor but the differences are fairly minor.
 
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