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?
It's interesting that even the 8-bit 68HC11 have versions with support, albeit minimal, for fractional format. The E variants are perhaps the earliest to provide such support. Nonetheless, the fractional data format might have already been used even in early computers.