Texas Instruments TMS320C67X/C67X+ DSP - Manual (Page 237)

Multiply Unsigned 16 LSB x Signed 16 LSB MPYUS
3-177 Instruction Set SPRU733
Example MPYUS .M1 A1,A2,A3
Before instruction 2 cycles after instruction
A1 1234 FFA1h 65441 ‡ A1 1234 FFA1h
A2 1234 FFA1h −95 † A2 1234 FFA1h
A3 xxxx xxxxh A3 FFA1 2341h −6216895
† Signed 16-LSB integer
‡ Unsigned 16-LSB integer