Computer Science Architecture question.

Consider a 3- address register-to-register lood (siere ercultecture , which allows addressing only rejises en criture tic goesonens (ie. ADDO), menou addressing is erb. en lood and store instructens Ci.e. Lormand ST com). While the assenbly code that comptes the expressen PxQtRxS and Staps the result on variable y