Notes

All available at: https://hdlfactory.com/bazel-registry/ if you are willing to use bazel.

Github repo: https://github.com/filmil/fshlib

The other day, I was pondering whether to keep setting particular bazel version in projects. I even removed some, to see what would become of it.

Details at: https://github.com/filmil/rules_shar

Find the project page at: https://github.com/filmil/bazel_debian_rootfs

This is another piece of news in my quest for hermetic, ephemeral, and reproducible builds (“HER”). If you read my articles in the past months or so, you may have noticed that I am looking for good ways of creating completely hermetic, ephemeral, reproducible, but also practical builds.

This is a collection of links to interesting articles and knowledge sources about the Bazel build system that I found. I’m motivated to do this after spending considerable time developing a thing that already existed. Just because I was not following the “right” communities I basically wasted a lot of effort reinventing a wheel. Useful wheel, but reinventing nevertheless.

This is another piece of news in my quest for hermetic, ephemeral, and reproducible builds (“HER”). If you read my articles in the past months or so, you may have noticed that I am looking for good ways of creating completely hermetic, ephemeral, reproducible, but also practical builds.

Update 2025-10-19: I made a searchable index of modules available from my registry at https://www.hdlfactory.com/bazel-registry.

See at: https://github.com/filmil/lit2md

This guide explains how to properly constrain a digital design with multiple clocks in an XDC (Xilinx Design Constraints) file, specifically for use in Vivado batch mode. We’ll cover primary clocks, generated clocks, and the relationships between them.

Find the project page at https://github.com/filmil/bazel_rules_bt

I asked Gemini to teach me about the VHDL resolved signals. What you read below is the result.

They say that no good deed goes unpunished. Here’s an example of a footgun in VHDL which stems from in my view an eminently reasonable desire to keep the entity interface definitions compact.

I asked Gemini to teach me the VHDL type conversions. What you read below is the result. An annoying generated podcast will be available for a while.

I updated the repository https://github.com/filmil/vivado-docker/ with the changes required to package Vivado 2025.1. As of this writing, version 2025.1 is the last published version. I hope that the updated version will remove some of the bugs I discovered in the previous version I dockerized, which was 2023.2.

This is a run-down of tips and tricks for the use of rules_nixpkgs, a rule set for bringing in nix packages for use in bazel.

Cross-posted from the original at https://github.com/filmil/bazel-rules-bid

Other formats:

A quick note about correct use of glbl.v in a Verilog simulation in Vivado. This note is way less confusing than any notes you may find elsewhere on the Internet.

From: https://github.com/filmil/go-vcd-parser

Reusing the general approach from this post gives a way for setting Shift_L+Shift_R as layout change:

$readmemh is a Verilog directive that allows you to initialize an array. It works differently in simulation compared to synthesis. In simulation, this directive behaves as a “read file into array”. In synthesis, this directive behaves as a repository of initial values for, say, block RAM.

Program your FPGA with a one-liner command. It’s a kind of magic.

This is something seldom known, and a very sharp corner to cut yourself on. But you really want to know if you are using nix.

I present to you https://github.com/filmil/bazel_rules_ghdl: a set of bazel rules for converting VHDL into Verilog.

This article assumes that you have bazel installed via the bazelisk method.

Here is how I install bazel. I use this installation method on all of my machines. I do not think it is practical to go about this any other way. It is implied in all of my writings about bazel.

The repository https://github.com/filmil/bazel_rules_gcc_riscv64_baremetal contains bazel rules that can be used for a hermetic bare metal GCC cross-compiler for a 64-bit RISC-V machine, running in M-mode.

These are some tips and tricks for lazygit that I keep forgetting how to do.

Here is how you can set up a hardware server (hw_server) in AMD Vivado 2023.2, in such a way that you can move your workbench to a virtual machine in your cloud of choice - mine is GCP - but program a device which is attached to a machine that’s close to you.

I accidentally bought the Google Nest 2nd Generation Router when I needed an Access Point.

This short note defines the notions of hermetic, ephemeral and reproducible software build, as used in my writing.

I bother with bazel.

If you are in a hurry, fast forward to https://github.com/filmil/bazel_local_nix

Perhaps obvious in retrospect, but it is not possible for a bazel build artifact to generate a named pipe in the filesystem.

After a lengthy search I found the below article that explains the use of Unix domain sockets in go:

If this advice helped you, let me know.

TIM-011 was an 8-bit teaching computer that was ostensibly developed by IMP in what is now Serbia.

TIM-011 was an 8-bit teaching computer that was ostensibly developed by IMP in what is now Serbia.

https://github.com/filmil/bazoekt

Entire BUILD.bazel:

TIM-011 was an 8-bit teaching computer that was ostensibly developed by IMP in what is now Serbia.

I was a bit hard pressed to find all the proper work attribution. Please let me know if you have data to contribute.

A while back I wanted to make a hermetic environment for repeatably running Docker tooling.

This is my cheat sheet for migrating VimScript into Lua. Things I often forget. There are places to learn about Lua use in Neovim . But, for some reason, I could not find side-by-side examples of VimScript vs Lua for quick migration. So I decided to start my own.

Often needed little bits of git knowledge that I tend to forget.

Often needed little bits of bazel knowledge that I tend to forget.

Here is an example python Flask app built with Bazel. See README.md for instructions.

We recently became Tesla owners, as our old car unexpectedly gave out. We were expecting to get at least 1 more year out of it. But it was not meant to be.

Adapted from the bazel-discuss mailing list.

The bazel build system has rules available to build C or C++ code from external repositories that use other more “conventional” build tools. By this I mean the usual suspects: GNU autotools, GNU make and cmake.