An interesting non-free alternative is the SEGGER Runtime Library [1] which works with GCC, but with smaller code size than newlib-nano and significantly faster

An interesting non-free alternative is the SEGGER Runtime Library [1] which works with GCC, but with smaller code size than newlib-nano and significantly faster floating point emulation [2] for processors like the Cortex M3 or RISCV wih no FPU. It would be interesting to see if newlib-nano or picolibc could use these tricks. [1] https://www.segger.com/products/development-tools/runtime-library/ https://www.segger.com/products/development-tools/runtime-li... [2] https://blog.segger.com/floating-point-face-off/ https://blog.segger.com/floating-point-face-off/