if (a[0].Type != obj.TYPE_REGREG) || (a[2].Type != obj.TYPE_REGREG) {
					p.errorf("invalid addressing modes for 1st or 3rd operand to %s instruction, must be register pair", op)
					return
				}
				// For ARM64 CASP-like instructions, its 2nd destination operand is register pair(Rt, Rt+1) that can
				// not fit into prog.RegTo2, so save it to the prog.RestArgs.
				prog.AddRestDest(a[2])
			default:
				prog.From = a[0]