5. Emacs

Emacs is a powerful editor and much more. Being a GNU project it also comes with a GDB integration that also works with the Calypsi debugger.

You will need to use the GDB-MI mode for Emacs which is based on the MI (Machine Interface) protocol. Old GDB integrations for Emacs will not work with Calypsi debugger.

5.1. Starting

It is easy to start the Calypsi debugger on a recent Emacs, simply use the M-x gdb command. Emacs will then prompt for the command line to use. Enter something like:

dbnut -i mi --load-module /path-to/41cx.mod mybinary

Replace /path-to/ with the path to your HP-41 operating system image. Here we are using an image for the HP-41CX.

We also need to provide the path to the ELF/DWARF binary you have built with the Calypsi tool chain, which is the image to debug. In order to have proper debugging information you need to build with the -g option.

5.2. Stopping

Simply issue the quit command on the debugger command line inside Emacs.

5.3. Many windows mode

Out of the box Emacs/GDB is typically used with a command line window 1 and a source window.

With GDB-MI it may be a good idea to issue the command M-x gdb-many-windows which configures Emacs with a set of useful windows for debugging. Here you will find a command line window that works like the usual console mode (with command completion and everything). A register window that updates as you step around is also available. To top it off, your source buffer now shows the line you are at with a solid arrow. You can set breakpoints by clicking in the fringe of the source buffer.

More information

The official documentation can be opened inside Emacs using the M-x info command.

Select Gdb (takes you to Debugging with GDB), then select Emacs (takes you to Using GDB under GNU Emacs). Here you should also find a link to GDB Graphical Interface which describes the Many Windows mode in detail.

Footnotes

1

A window in Emacs is a view to a buffer. (A buffer often corresponds to an open file, but it does not have to be tied to a file.)