RichCini
Veteran Member
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!
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!