redoste/fx-CG50_Manager_PLUS-gdbserver

A GDB Remote Serial Protocol implementation that hooks to fx-CG50 Manager PLUS allowing to debug code running on the emulated calculator

fx-CG50 Manager PLUS - gdbserver

A GDB Remote Serial Protocol implementation that hooks to fx-CG50 Manager PLUS allowing to debug code running on the emulated calculator.

• Demo (new at 33e6ab4) : https://youtu.be/3ucQ3VpzQxI : This demo features the debugging of an add-in compiled with GCC and demonstrates the usage of software and hardware breakpoints.
• Demo (old at 7a848ec) : https://youtu.be/wGWVSqz2svo : This demo features the debugging of an add-in written in assembler and demonstrates the modification of general purpose registers.

Build :

Binaires are built by GitHub Actions and avaliable in releases if you don't want to do it yourself.

Using MSVC on Windows

• Install NASM and Visual Studio with its C compiler
• From the Start menu open the x86 Native Tools Command Prompt

> cd C:\path\to\git\repo
> set PATH=%PATH%;"C:\Program Files\NASM"
> msbuild

• The binary will be available in Release\CPU73050.dll

Using MinGW-w64 on Windows with Cygwin

• Install Cygwin and in the graphical installer make sure to check ninja, nasm and mingw64-i686-gcc-core
• Open a new Cygwin terminal

$ cd /cygdrive/c/path/to/git/repo
$ ninja

• The binary will be available in obj/CPU73050.dll

Using MinGW-w64 on Windows with MSYS2

• Install MSYS2
• Open a new MSYS2 terminal

$ pacman -S ninja nasm mingw-w64-i686-gcc
$ cd /c/path/to/git/repo
$ PATH=$PATH:/mingw32/bin/ ninja

• The binary will be available in obj/CPU73050.dll

Using MinGW-w64 on Linux

• Install NASM, ninja and an i686 build of MinGW-w64.
• NASM and ninja will probably be called as is in your package manager but MinGW-w64 will be harder to find, try searching for mingw and i686 (e.g. on Arch Linux it's mingw-w64-gcc, on Debian gcc-mingw-w64-i686 or on Void Linux cross-i686-w64-mingw32).
• Open a terminal

$ cd /path/ro/git/repo
$ $EDITOR build.ninja # Depending on your distribution you may want to update $cc and $cross-prefix
$ ninja

• The binary will be available in obj/CPU73050.dll

Usage :

• Rename CPU73050.dll to CPU73050.real.dll in fx-CG50 Manager PLUS installation folder
• Copy the new CPU73050.dll in the same folder
• When starting fx-CG50 Manager PLUS, connect with GDB via your interface of choice

GDB Interfaces :

fx-CG50 Manager PLUS - gdbserver provides 3 ways to connect to the debugger. You can select one by adding the following argument to fx-CG_Manager_PLUS_Subscription_for_fx-CG50series.exe command line : /gdb:[interface name]:[interface options].

Name	Option	Description
tcp	port	TCP socket listening on IPv4 0.0.0.0 with the specified port
com	COMn	Serial port COMn
wine	path	Unix socket when fxCG50gdb is running through Wine on */Linux

For some reason the tcp interface seems to be pretty slow. We recommand using com or wine when possible.

Major Issues :

This software is still in development, many problems remain.

• The server waits for a continue command from GDB before starting. If this command takes too long to arrive, fx-CG50 Manager PLUS freaks out and thinks the installation is corrupted and will refuse to start.
• Writing to memory and by extension putting breakpoints and single stepping are still not implemented. You must use the BRK (0x003B) instruction to trigger the debugger. This instruction is documented here but most assemblers/disassemblers/debuggers/emulators/CPUs seems to not implement it. It might just not exist.
• The offsets of important values in memory are hard-coded, you should check include/fxCG50gdb/emulator_offsets.h to make sure you have the correct version of CPU73050.dll.
• Reading to some weird addresses might segfault.
• It has only been tested with the GRAPH90+ E mode, other modes might have other issues or be completely broken.
• It is slow.