The Zimop extension defines 8 MOP instructions named MOP.RR.n, where n is an integer between 0 and 7, inclusive. Unless redefined by another extension, this instruction simply writes 0 to X[xd]. Its encoding allows future extensions to define it to read X[xs1] and X[xs2], as well as write X[xd]. This is mop.rr.3 from the MOP.RR instruction family (n=3).
mop.rr.3 xd, xs1, xs2Type: R