# dup to "lo"
netdev test-netdev ingress 
  [ immediate reg 1 0x00000001 ]
  [ dup sreg_dev 1 ]

# dup to meta mark map { 0x00000001 : "lo", 0x00000002 : "lo"}
__map%d test-netdev b
__map%d test-netdev 0
	element 00000001  : 00000001 0 [end]	element 00000002  : 00000001 0 [end]
netdev test-netdev ingress 
  [ meta load mark => reg 1 ]
  [ lookup reg 1 set __map%d dreg 1 ]
  [ dup sreg_dev 1 ]