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P32W in a codespace

P32W's tools and emulators on a Linux machine of GitHub's, used from a web browser (a Chromebook will do): VS Code in the browser tab, with a terminal. Nothing to install.

Opening it

  • The first time: github.com/codespaces, New codespace, repository ksr/P32W, branch main, Create. Setting up takes about ten minutes, once: it builds both emulators and P32W Unix's disk (.devcontainer/setup.sh).
  • After that: github.com/codespaces and click it. It picks up where you left off.

Running P32W

In the terminal (Terminal, New Terminal):

tools/p32w

At the monitor's > type b to boot. Log in as ken (password p32) or root (root). halt shuts P32W down cleanly; Ctrl+] stops the emulator at once. tools/p32w -u runs the microcode-level emulator instead (slower, the real control store).

A second user at once: tools/p32w -T 2323, then in a second terminal python3 tools/p32term.py.

The debugger, in the browser

python3 tools/p32dbg

P32W in the emulator with its screen, its console, the registers, the code, memory and breakpoints on one page, which opens in a new tab by itself (GitHub forwards the port, to an address only you can reach; the Ports tab has it again). python3 tools/p32dbg -u runs the microcode-level emulator and shows the CPU's insides cycle by cycle. It starts stopped, at the reset, as debuggers do: press Run and the monitor's > appears on the console. Then click the console, type b and Enter to boot (keys typed while it is stopped wait for Run); click the screen to log in on it too. Like tools/p32w, it uses your disk, software/build/disk.img: halt P32W as root before Quit on the page ends it, to leave the disk clean. tools/p32dbg/README.md says more.

Your work

  • On P32W: the disk, software/build/disk.img, keeps its files between sessions, even after the codespace stops. It is not in git.
  • Getting a file out, to commit it: sync (or halt) in P32W first, then in a terminal 
    python3 tools/p32fs.py cat software/build/disk.img /home/ken/prog.c > prog.c
  • Putting a file in, with P32W halted: 
    python3 tools/p32fs.py put software/build/disk.img prog.c /home/ken/prog.c
  • Careful: make -C software disk builds a fresh disk over this one. Copy your files out first. Nothing else does: rebuilding the container keeps it.
  • After a git pull: make -C emulator builds the emulators again from the new sources (tools/p32w builds them only when they are missing).
  • The host side: edit in VS Code, make -C software builds, cd emulator && make test runs every test (about an hour on this machine; three that need a Mac's own tools print SKIP). Commit and push as usual, and pull on the Macs.

Good to know

  • The codespace stops itself after 30 minutes idle (up to 4 hours: github.com/settings/codespaces). A running P32W stops with it; halt it first, so the disk is clean.
  • GitHub's free monthly allowance covers some 60 hours on this 2-core machine (GitHub Free: 120 core-hours and 15 GB-months; Pro: 180 and 20; github.com/settings/billing). With no payment method on file, use stops there until the next month; with one, a $0 Codespaces budget with "Stop usage when budget limit is reached" keeps it free. A stopped codespace still counts as storage: delete the ones you no longer use.
  • KiCad is not here: the boards stay on the Macs.