REG_Z28,
		REG_Z29,
		REG_Z30,
		REG_Z31:
		if ctxt.Arch.Family == sys.I386 {
			goto bad
		}
		fallthrough

	case REG_AX,
		REG_CX,
		REG_DX,
		REG_BX,
		REG_BP,
		REG_SI,
		REG_DI,
		REG_X0,
		REG_X1,
		REG_X2,
		REG_X3,
		REG_X4,
		REG_X5,
		REG_X6,
		REG_X7,
		REG_Y0,
		REG_Y1,
		REG_Y2,
		REG_Y3,
		REG_Y4,