armv4t-none-eabi

Tier 3

Bare-metal target for any cpu in the ARMv4T architecture family, supporting ARM/Thumb code interworking (aka a32/t32), with ARM code as the default code generation.

In particular this supports the Gameboy Advance (GBA), but there's nothing GBA specific with this target, so any ARMv4T device should work fine.

Target Maintainers

Requirements

The target is cross-compiled, and uses static linking.

The linker that comes with rustc cannot link for this platform (the platform is too old). You will need the arm-none-eabi-ld linker from a GNU Binutils targeting ARM. This can be obtained for Windows/Mac/Linux from the ARM Developer Website, or possibly from your OS's package manager.

This target doesn't provide a linker script, you'll need to bring your own according to the specific device you want to target. Pass -Clink-arg=-Tyour_script.ld as a rustc argument to make the linker use your_script.ld during linking.

Building Rust Programs

Because it is Tier 3, rust does not yet ship pre-compiled artifacts for this target.

Just use the build-std nightly cargo feature to build the core library. You can pass this as a command line argument to cargo, or your .cargo/config.toml file might include the following lines:

[unstable]
build-std = ["core"]

Most of core should work as expected, with the following notes:

  • the target is "soft float", so f32 and f64 operations are emulated in software.
  • integer division is also emulated in software.
  • the target is old enough that it doesn't have atomic instructions.

Rust programs are output as ELF files.

For running on hardware, you'll generally need to extract the "raw" program code out of the ELF and into a file of its own. The objcopy program provided as part of the GNU Binutils can do this:

arm-none-eabi-objcopy --output-target binary [in_file] [out_file]

Testing

This is a cross-compiled target that you will need to emulate during testing.

Because this is a device-agnostic target, and the exact emulator that you'll need depends on the specific device you want to run your code on.

For example, when programming for the Gameboy Advance, the mgba-test-runner program could be used to make a normal set of rust tests be run within the mgba emulator.