# AdaCasio

Building and developing Ada applications for the **Casio fx-CG50**

---

The Casio fx-CG50 (from here on only called CG50) uses the SuperH architecture. Specifically a custom SH4-A chip. To be able to develope Add-ons, we first need to compile gcc with Ada and SuperH support.

> [!NOTE]
> This guide is mostly based on [Lephenixnoir](https://git.planet-casio.com/Lephenixnoir) guides for building fxSDK manually.
> I have changed a few parts to add Ada support _without_ an Ada Runtime (Later project)

## Building a GNAT cross compiler 

We start by downloading the `binutils` and `gcc` source code.

```bash
wget -O binutils.tar.gz "https://ftp.gnu.org/gnu/binutils/binutils-2.46.0.tar.gz"
wget -O gcc.tar.gz "https://ftp.gnu.org/gnu/gcc/gcc-15.2.0/gcc-15.2.0.tar.gz"
tar -xf binutils.tar.gz
tar -xf gcc.tar.gz
```

> [!NOTE]
> You need a working ada compiler to compile ada. If you don't have gnat available in your repo, you can compile a stage1 gcc compiler.
> For my own sanity sake, I'll just assume that you already have gnat installed on your system.

Prepare the build environment to configure the tools.

```bash
mkdir build-binutils build-gcc sysroot
```

`sysroot` is where _gcc_ and _binutils_ is going to be installed at. The `build-*` directories is where the tools are going to be build at. But before we do that we first have to configure them.

### Configuring binutils

```bash
cd build-binutils
../binutils-*/configure                 \
  --prefix="$(pwd)/../sysroot"          \
  --target="sh3eb-elf"                  \
  --with-multilib-list="m3,m4-nofpu"    \
  --program-prefix="sh-elf-"            \
  --enable-libssp                       \
  --enable-lto
```

You might ask yourself now why we chose these flags. Here I have tried to lay out _why_ we use some of these flags.

| Flag                   | Meaning                                               |
|----------------------- | ----------------------------------------------------- |
| --prefix               | The install path. In our case it's `sysroot`          |
| --target               | What our target architecture is. The CG50 uses SuperH |
| --with-multilib-list   | TODO: for what is that?                               |
| --program-prefix       | prefix of the binuitls tools                          |
| --enable-libssp        | No Idea                                               |
| --enable-lto           | Link Time Optimization. Glue code faster together     |

### Compiling binutils

We now compile `binutils` with our custom configuration using 

```bash
make -j$(nproc)
make install-strip
```

We now configure and install `gcc` using the same steps but with different flags.

### Configuring GCC (Part 1)

We will first compile a working C cross compiler without a libc and add it later on to compile gcc with C++ and Ada support.

```bash
cd ../build-gcc
../gcc-*/configure                        \
  --prefix="$(pwd)/../sysroot"            \
  --target="sh3eb-elf"                    \
  --with-multilib-list="m3,m4-nofpu"      \
  --enable-languages="c,c++,ada"          \
  --without-libada                        \
  --without-headers                       \
  --program-prefix="sh-elf-"              \
  --enable-libssp                         \
  --enable-lto                            \
  --enable-clocale="generic"              \
  --enable-libstdcxx-allocator            \
  --disable-threads                       \
  --disable-libstdcxx-verbose             \
  --enable-cxx-flags="-fno-exceptions"
```

TODO: Da fuck all these flags for?
| Column1   | Column2    |
|--------------- | --------------- |
| --disable-libada | We will be adding our own runtime |
| Item1.2   | Item2.2   |
| Item1.3   | Item2.3   |
| Item1.4   | Item2.4   |


### Compiling GCC

We now compile `gcc` the same way we did `binutils`.

```bash
make -j$(nproc) all-gcc all-target-libgcc
make install-strip-gcc install-strip-target-libgcc # TODO: may need to add Ada stuff?
```

We now have successfully cross compiled gcc. However we still need to add a libc and compile gnat. 
For that we will have to install the required headers into the correct coresponding direcotry

```bash
cd ..
export PATH="$PATH:$(pwd)/sysroot/bin"
PREFIX="$(sh-elf-gcc --print-file-name=.)"
```

The `PREFIX` directory is where gcc is going to look for all the system headers. 

### Adding libc

We will now install a libc implementation that works on the CG50. For that we will use [OpenLibm](https://git.planet-casio.com/Lephenixnoir/OpenLibm) and [libfxcg](https://github.com/Jonimoose/libfxcg.git)

```bash
git clone https://github.com/Jonimoose/libfxcg.git
cd libfxcg/libc
```
replace all the `sh3eb-` with `sh-elf` 
```bash
make
cp lib/* ../sysroot/lib/
cp -r include/* ../sysroot/lib/gcc/sh3eb-elf/15.2.0/include/
```

Go back to build-gcc and run

```bash
make -C gcc cross-gnattools
make install-strip
```

> [!NOTE]
> There is also gint and vhex form the repo but those target also other calculators that I don't have access to.
> For my own sanity sake I'll just stick with the casiowin-cg

## Compiling GCC (Part 2)

> [!WARNING]
> Building gcc with c++ does not work

Build now the c++ support with 

```bash
make -j$(nproc) all-target-libstdc++-v3
make install-strip-target-libstdc++-v3
```

---

## packaging the binary

We will need to build `mkg3a` to package the binary. 

```bash
git clone https://gitlab.com/taricorp/mkg3a.git
mkdir build
cd build
cmake ..
make
make install/local # do not want to install it to the system but to 
```

## Adding our custom compiler to GPRBuild 

TODO: look into ironclad gprbuild integration


Sources used:
 - https://osdev.wiki/wiki/GNAT_Cross-Compiler
 - https://www.planet-casio.com/Fr/forums/topic12970-1-tutoriel-installation-manuelle-de-gcc-et-du-fxsdk.html
 - https://gcc.gnu.org/install/configure.html
 - https://git.planet-casio.com/Lephenixnoir/fxsdk
 - https://prizm.cemetech.net/Mkg3a/

---
Copyright (c) 2026 Ada Orbit. All Rights Reserved.