Assembly Language Coding, Legacy 8088 CPU Diagnostics ROM

We are preparing to offer a kit for hobbyists to build a clone of the IBM PC 5150 Motherboard ( 8088 CPU, 64-256 KB RAM, ISA bus, etc.) The original IBM BIOS resides on an 8K ROM in location U33. It is possible to replace the 8K BIOS ROM with another chip programmed with a diagnostic program, known as the Landmark / Supersoft (LM/SS) ROM. The diagnostic ROM performs a series of tests on the hardware. A photo of a typical display screen is attached.

The diagnostic LM/SS program only works with a Monochrome Display Adapter (MDA) or Color Graphics Adapter (CGA). We would like to modify the program to work with a VGA card and display. We only have the 8K binary file of the original program, which is attached. We have used a dissassembly program on the binary to view the source code, also attached.

The LM/SS program communicates directly with the hardware. Recall that this ROM is replacing the BIOS ROM, so normal calls to interrupt functions are not available.

We are looking for proposals on this project. A first milestone might be creating an assembly routine that can display simple text on a VGA card from a cold boot. We can provide a PC motherboard, power supply, blank ROM chips and VGA cards as a development platform. Alternately, we can burn ROM chips with test code and install in our hardware for proof of principle trials. Advanced contractors may have other approaches to solving this problem, such as writing new code (with similar functionality) from scratch.

Electronics Software Testing x86/x64 Assembler

Project ID: #2440406

About the project