register_rule
case register_rule: /* CFA = offset + source_reg */
case register_rule: /* RA = offset + source_reg */
case register_rule: /* target_reg = offset + source_reg */
f_state[val1].rule = register_rule;
f_state[CF_ADDR].rule = register_rule;
f_state[CF_ADDR].rule = register_rule;
enum register_rule rule;