abq$xs (4) --- add an element to the bottom of a queue   06/28/82


            _C_a_l_l_i_n_g _I_n_f_o_r_m_a_t_i_o_n

                 logical function abq$xs (qu, addition)
                 shortcall abq$xs (4)

                 queue_control_block qu
                 untyped addition

                 Library: shortlb
                 Also declared in =incl=/shortlb.r.i


            _F_u_n_c_t_i_o_n

                 This  routine  adds  a  16  bit  quantity  (the  contents of
                 'addition') to the bottom of a circular queue (deque) struc-
                 ture at 'qu'.  The function result is TRUE if  the  addition
                 was done, FALSE if the queue was full (before the call).

                 The   declaration   'queue_control_block'   is   defined  in
                 =incl=/shortlb.r.i; this file should  be  included  if  this
                 routine is used.


            _I_m_p_l_e_m_e_n_t_a_t_i_o_n

                 Implemented  as  a  simple  PMA  routine  entered via a JSXB
                 (shortcall).  The hardware ABQ instruction  is  executed  on
                 the arguments.

                 Note that any routine using this call must be compiled using
                 the "-q" option of 'fc'.


            _A_r_g_u_m_e_n_t_s _M_o_d_i_f_i_e_d

                 qu


            _B_u_g_s

                 The routine makes no attempt to validate the argument passed
                 as a queue control block.

                 Locally supported.


            _S_e_e _A_l_s_o

                 atq$xs  (4),  fc  (1),  mkq$xs  (4), rtq$xs (4), rbq$xs (4),
                 tsq$xs (4), _S_y_s_t_e_m _A_r_c_h_i_t_e_c_t_u_r_e _R_e_f_e_r_e_n_c_e _G_u_i_d_e  (Prime  PDR
                 3060)






            abq$xs (4)                    - 1 -                    abq$xs (4)