wantImmI(ctxt, ins, ins.imm, 21)
	wantIntReg(ctxt, ins, "rd", ins.rd)
	wantNoneReg(ctxt, ins, "rs1", ins.rs1)
	wantNoneReg(ctxt, ins, "rs2", ins.rs2)
	wantNoneReg(ctxt, ins, "rs3", ins.rs3)
}

func validateRaw(ctxt *obj.Link, ins *instruction) {
	// Treat the raw value specially as a 32-bit unsigned integer.
	// Nobody wants to enter negative machine code.
	if ins.imm < 0 || 1<<32 <= ins.imm {