gistfile1.txt

read_tag_val() {

  tag = read_u8();
  
  tag_type = tag & 0b00000111;
  tag_expanded = tag & 0b00001000;
  tag_adv_expanded = tag & 0b00010000;
 
  if tag_expanded == 0 {
    val = tag >> 4;
  } else if tag_adv_expanded == 0 {
    expand_val = read_u8();
    val = (tag >> 5) << 8;
    val |= expand_val;
  } else {
    TODO
  }

  (tag_type, val)
}

read_code() {
  while true {
    opcode = read_u8();
    arity = lookup_arity_from_optab(opcode);
    
    arg_num = 0;
    while arg_num < arity {
      (tag, val) = read_tag_val();
      match tag {
        0 => //val is label
        2 => //val is atom
        3 => //val is x reg
        4 => //val is y reg
        5 => //val is failure label
        7 => {
          val is extended tag
          match val {
            0 => //float literal, not codegen anymore, maybe handle later,
            1 => { //extended arity
              assert arg_num+1 == arity;
              (l_tag, l_val) = read_tag_val();
              assert l_tag == 0;
              arity += l_val;
            }
            4 => { //literal
              (l_tag, l_val) = read_tag_val();
              assert l_tag == 0;
              l_val is literal index
            }
          }
        }
      }
    }
  }
}