Summary

Colin Walls examines the trade-offs between hand-written assembly and C in embedded firmware, showing cases where modern compilers produce equal or better code. Readers will learn why C often yields smaller, faster, or safer binaries for ARM and RISC-V microcontrollers and when assembly is still appropriate.

Key Takeaways

• Measure performance and code size with real benchmarks before deciding to rewrite C in assembly.
• Leverage compiler optimizations (LTO, PGO) and intrinsics to get near-assembly performance without hand-coding instructions.
• Use assembly selectively for proven hotspots, tight interrupt handlers, or hardware init where compilers fall short.
• Apply disciplined testing and review when mixing assembly and C to avoid calling-convention and ABI bugs.
• Prefer modern C with well-chosen compiler flags for maintainability and portability unless a clear, measured benefit exists.

Who Should Read This

Embedded and firmware engineers with some microcontroller experience who need to decide whether to hand-write assembly or rely on C and compiler optimizations for ARM/RISC-V projects.

Still RelevantIntermediate

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