Follow the OS-specific instructions below.

# Linux

Install [**devkitARM**](http://devkitpro.org/wiki/Getting_Started/devkitARM).

Make sure that there is an environment variable called DEVKITARM with the path of the directory before the "bin" directory containing "arm-none-eabi-as", "arm-none-eabi-cpp", "arm-none-eabi-ld" and "arm-none-eabi-objcopy".

Then get the compiler from https://github.com/pret/agbcc and run the following commands.

```
./build.sh
./install.sh PATH_OF_POKEEMERALD_DIRECTORY
```

Then in the pokeemerald directory, build the tools.

```
./build_tools.sh
```

Finally, build the rom.

```
make
```

# Windows

Install [**devkitARM**](http://devkitpro.org/wiki/Getting_Started/devkitARM).

Then get the compiled tools from https://github.com/pret/pokeruby-tools. Copy the `tools/` folder over the `tools/` folder in your pokeemerald directory.

You can then build pokeemerald using `make` in the MSYS environment provided with devkitARM.

# Mac

Installing pokeemerald on a Mac requires macOS >= 10.12 (Sierra or higher).

To get pokeemerald up and running, run the following commands in Terminal:

Make sure you have the right compilers.

```
xcode-select --install
```
   
Download a [devkitPRO pacman](https://github.com/devkitPro/pacman/releases/tag/v1.0.0) package (`.pkg`) and install using the native Installer.

This will install the devkitPRO package in `/opt/devkitpro`.

You must install devkitARM using

```
sudo dkp-pacman -S devkitARM 
```

Then set environment variables 

```
export DEVKITPRO=/opt/devkitpro
echo "export DEVKITPRO=$DEVKITPRO" >> ~/.bashrc
export DEVKITARM=$DEVKITPRO/devkitARM
echo "export DEVKITARM=$DEVKITARM" >> ~/.bashrc
```

Now download and install the game's compiler from <https://github.com/pret/agbcc>. You should download and unpack the `.zip` and move the folder to the same folder holding pokeemerald. 

```
cd /PATH/TO/agbcc/
./build.sh
./install.sh /PATH/TO/pokeemerald 
```

Build the necessary tools
```
cd /PATH/TO/pokeemerald
./build_tools.sh
```
And finally the ROM should be ready to build
```
make
```