Programming the strange "high res" adapter (two full-length boards with a jumper cable, something like 640x400x16) on my Sperry PC back in the day, I just soldered in a switch that connected NMI to ground and used it with basic tools like Borland Turbo Debugger. http://www.bitsavers.org/pdf/borland/turbo_assembler/Turbo_Debugger_2.0_User... I'd be running graphics code on the "high res" adapter, and have an MDA card with debugger running on the monochrome display. Cheers, Garrett On Wed, 10 Jun 2020 19:13:14 -0400 Richard Cini via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:
All –
I’m working on an S100 project with my Gazelle (a VGA board) which is based on a standard Trident VGA chip. The BIOS on the video board relies on a PC BIOS (which doesn’t exist for the Gazelle) so I’ve had to hack something together for it to make it work. The BIOS is barfing somewhere in the initialization, but it’s a hard crash so resetting it to regain control destroys the context. I’m running under MSDOS 2.01.
I remember that there were debuggers like Periscope or SoftICE that could trap NMI, but I need it to be pure character-based like MS-DOS debug. Does anyone know of any debuggers like this? There was one by Paul Vojta, which I have the code for, but that doesn’t trap NMI. I wonder if I could just have the NMI call INT 03H (debug break) since they all trap that.
Any thoughts or help appreciated. Thanks!
Rich
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Rich Cini