# Address Resolution Protocol

This unit contains an ivalmap [lib/ival] pointing to [com/ip4]'s active frame
payload.

## API

### ivalmap of an ARP structure

  $00 BE2 HRD
  $02 BE2 PRO
  $04 N1  HLN
  $05 N1  PLN
  $06 BE2 OP
  $08 REF SHA

Because SHA, SPA, THA and TPA are of variable length, the 3 last fields can't
be regular ivalmap fields

### Words

SPA
THA
TPA ( -- a )
  Yield the address of the 3 last fields of the ivalmap, taking HLN and PLN in
  account.
