Name		Name	Last commit message	Last commit date
parent directory ..
rust		rust
sdk_app_rust		sdk_app_rust
Makefile		Makefile
README.md		README.md
gen-bindings.sh		gen-bindings.sh
genromap		genromap
proj_config.mk		proj_config.mk
riscv32imac-unknown-none-elf.json		riscv32imac-unknown-none-elf.json
riscv32imacf-unknown-none-elf.json		riscv32imacf-unknown-none-elf.json
riscv64gc-unknown-none-elf.json		riscv64gc-unknown-none-elf.json
run.sh		run.sh

README.md

Rust Firmware for BL602 IoT SDK

This BL602 firmware shows how we may create Rust firmware with the BL602 IoT SDK. Read the article...

Rust source code for the BL602 firmware is here...

Run this script to build, flash and run the BL602 Rust firmware...

This script links the compiled Rust code into the BL602 firmware by overwriting the compiled rust_app Stub Library...

The script uses a Custom Rust Target riscv32imacf-unknown-none-elf...

This Custom Rust Target is a minor tweak of the standard Rust target riscv32imac-unknown-none-elf...

We set features to +m,+a,+c,+f to generate RISC-V binaries with Single-Precision Hardware Floating-Point (+f)
We set llvm-abiname to ilp32f to support Single-Precision Hardware Floating-Point for the Application Binary Interface

We can't use the standard target riscv32imac-unknown-none-elf because...

BL602 IoT SDK was compiled with gcc -march=rv32imfc -mabi=ilp32f

(Single-Precision Hardware Floating-Point)
Linker fails with error can't link soft-float modules with single-float modules

How did we figure out the tweaks for the Custom Rust Target?

By comparing the Rust Target Specs for riscv32imac-unknown-none-elf vs riscv64gc-unknown-none-elf...

Generated by...

rustc +nightly -Z unstable-options --print target-spec-json --target riscv32imac-unknown-none-elf

Read the Twitter Thread...