6.375 Final Project: Apollo Guidance Computer

A Bluespec System Verilog implementation of the Apollo Guidance Computer for an MIT 6.375 final project.

This project is heavily indebted to Ron Burkey's VirtualAGC; in particular it uses his UI components (like yaDSKY2), his assembler and validation suite, and of course his documentation of the AGC itself.

New Work

During the 2020 coronavirus epidemic Val and I started up work on this again, using the open source https://github.com/B-Lang-org/bsc compiler. We've started to clean up the work we did for 6.375 a few years ago, but things are still messy.

Prerequisites

• Bluespec: Follow the installation directions at https://github.com/B-Lang-org/bsc, and make sure the bsc binary is in your path.
• VirtualAGC compontents: Install yaDSKY2, yaYUL, and LM_Simulator from https://github.com/virtualagc/virtualagc, and make sure they are in your path.
• Submodules: Get the submodules fetched with git submodule update --init --recursive.

Compiling Programs

To compile a program into a VMH that can be loaded into the AGC's memory, run make $PROGRAM_NAME, like so:

$ make demo/demo.bin

Building and Running in Simulation

To build and run for Bluesim simulation, do the following, substituting demo for the name of a program you compiled above.

$ make simbuild
$ make simrun-demo

Now that you have the simulation running, start up the testbench in a second window:

$ make testbench

And finally start up the control UI. You can either use yaDSKY2 if you just want the keypad, or LM_Simulator for more control panels. Note that LM_Simulator won't start up unless the testbench is already serving the selected port.

$ LM_Simulator --port 19797

Adding a New Harness

In order to add a new harness, such as a new simulation type or a new FPGA transport type, you need to be able to call the following AGC functions:

• agc.memInit.request.put(MemInitLoad data) to initialize the program memory (only needed if you're not initializing the memory out-of-band)
• agc.hostIO.init(IOPacket packet) to initialize the I/O buffers.
• agc.memInit.InitDone() to mark the program memory as initialized. You must call this even if you're not using MemInit.InitLoad().
• agc.start(uint16_t addr) to actually start the AGC. You probably want to start it at 04001.
• agc.hostIO.hostIO.hostToAGC(IOPacket packet) to send data to the AGC's I/O channels.
• agc.hostIO.hostIO.agcToHost() => IOPacket to receive data from the AGC's I/O channels.

Major Todos

• The verification tests fail on test 64.01. It seems to be something about T3 or T4 not firing on the expected schedule, because 551c364744347da1bc90eac0ad1ba515171e11a2 broke them.
• The Luminary self-checks fail on the first test. The debugging info is that V05N09E gives a display of 1407/1102/0, and V05N08E gives a display of 3411/66100/1. The Luminary documentation explains what these numbers mean, though I haven't investigated them.
• Add HANDRUPT and associated interrupts and registers. See branch boorstin-handrupt for progress.