mu/shell/README.md

A prototype shell for the Mu computer

Currently runs a tiny subset of Lisp. Steps to run it from the top-level:

1. Build it:

$ ./translate shell/*.mu      # generates code.img

2. Run it:

$ qemu-system-i386 -m 2G code.img

or:

$ bochs -f bochsrc            # _much_ slower

To save typing in a large s-expression, create a secondary disk for data:

$ dd if=/dev/zero of=data.img count=20160

Load an s-expression into it:

$ echo '(+ 1 1)' |dd of=data.img conv=notrunc

You can also try one of the files of definitions in this directory (*.limg).

$ cat iterative-definitions.limg |dd of=data.img conv=notrunc

Now run with both code and data disks:

$ qemu-system-i386 -m 2G -hda code.img -hdb data.img

or:

$ bochs -f bochsrc.2disks

You can type in expressions, hit ctrl-s to see their results, and hit Tab to focus on the ... below and browse how the results were computed. Here's a demo. The bottom of the screen shows context-dependent keyboard shortcuts (there's no mouse in the Mu computer at the moment).

Improvements

If your Qemu installation supports them, one of these commandline arguments may speed up emulation:

• -enable-kvm
• -accel ___ (run with -accel help for a list of available options)

As a complete example, here's the command I typically use on Linux:

$ qemu-system-i386 -m 2G -enable-kvm -hda code.img -hdb data.img

Known issues

• There's no way to save to disk.

• Don't press keys too quickly (such as by holding down a key). The Mu computer will crash (and often Qemu will segfault).