Why the Cortex M4 instruction SMMUL (32 = 32 x 32b) preserves a redundant sign bit and discards one useful bit of information? What could possibly be the justification for such blatant disregard of the ISO/IEC TR 18037 standard Fract format?
daith, sorry if I posted that. I didn't have much time and about to log-out then but there was a young engineer (I've recently convinced to also study ARM instead of being too dedicated to AVR and PICmicro) who read your reply pertaining to SMULL/SMMUL and wondered if SMULL was excluded in Cortex-M4. I then decided to post such response, hoping that would help prevent some other readers, especially new users of Cortex-M, from also misinterpreting the info.
I was agreeing with you. Misinterpreting happens all the time and is very hard to guard against.