Day 38: Install the riscv-gnu-toolchain; compile your first binary
The RISC-V toolchain
The riscv-gnu-toolchain gives you a cross-compiler (riscv32-unknown-elf-gcc), assembler, linker, and the binutils (objdump, readelf) that turn C and assembly into RV32I ELF binaries — and let you *see* the machine code. This is the toolchain your ISS will consume today and ChipX will boot in Stage 4, so setting it up now pays off for the rest of the roadmap.
# compile to RV32I (no OS, no standard startup)
riscv32-unknown-elf-gcc -march=rv32i -mabi=ilp32 \
-nostdlib -O2 -c hello.c -o hello.o
# see the machine code — your hand-assembly, verified
riscv32-unknown-elf-objdump -d hello.o
# a tiny program to try:
# int main(void){ int s=0; for(int i=0;i<10;i++) s+=i; return s; }Bare-metal from the start
Compile with -nostdlib/-march=rv32i: ChipX has no operating system and only the base integer instructions. Getting comfortable with bare-metal builds now (no printf, no libc assumptions) is exactly the mindset Stage 4 firmware needs — and it keeps your test binaries small enough to trace instruction-by-instruction.
Key terms
- Cross-compiler
- A compiler that runs on your machine but emits code for a different target (here RV32I).
- ELF
- The executable/object file format holding machine code, symbols, and section layout.
- objdump
- A binutils tool that disassembles a binary back to human-readable assembly.
- Bare-metal
- Code that runs with no operating system or standard library beneath it.
Ship for Day 38
Why compile ChipX test programs with -march=rv32i -nostdlib?
