Floating Point Fun on Cortex-M Processors

In my recent post on the PSA Crypto API, I demonstrated the use of the API on two different MCUs: the nRF52840 and the ESP32-S3. In the case of the former, the ECDSA signature operation was eventually executed in a closed source library that manages communication between the Arm Cortex-M4 processor and the Arm TrustZone CryptoCell 310 security subsytem. Readers that ventured down the rabbit hole…