code: def p_jr(p):
      
      p[4] = Expr.makenode(Container('-', p.lineno(3)), p[4], Expr.makenode(Container(MEMORY.org + 2, p.lineno(1))))
      p[0] = Asm(p.lineno(1), 'JR %s,N' % p[2], p[4])
docs: asm : JR jr_flags COMMA expr
              | JR jr_flags COMMA pexpr