// ========== Copyright Header Begin ========================================== // // OpenSPARC T1 Processor File: lsu_rrobin_picker2.v // Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved. // DO NOT ALTER OR REMOVE COPYRIGHT NOTICES. // // The above named program is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public // License version 2 as published by the Free Software Foundation. // // The above named program is distributed in the hope that it will be // useful, but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // General Public License for more details. // // You should have received a copy of the GNU General Public // License along with this work; if not, write to the Free Software // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. // // ========== Copyright Header End ============================================ //////////////////////////////////////////////////////////////////////// /* // Description: Round-Robin Picker for 4 eventss. // (see description of picker at the end of this file) */ //////////////////////////////////////////////////////////////////////// // Global header file includes //////////////////////////////////////////////////////////////////////// `include "sys.h" // system level definition file which contains the // time scale definition //////////////////////////////////////////////////////////////////////// // Local header file includes / local defines //////////////////////////////////////////////////////////////////////// module lsu_rrobin_picker2 (/*AUTOARG*/ // Outputs so, pick_one_hot, // Inputs rclk, grst_l, arst_l, si, se, events, events_picked, thread_force ); input rclk ; input grst_l; input arst_l; input si; input se; output so; input [3:0] events ; // multi-hot; events that could be chosen input [3:0] events_picked ; // one-hot; events that were picked - same cycle as pick input [3:0] thread_force ; // multi-hot; thread events that have high priority output [3:0] pick_one_hot ; // one-hot wire clk; wire reset,dbb_reset_l ; wire [3:0] thread_force_pe_mask ; wire [3:0] pick_thread_force_1hot ; wire thread_force_events_sel ; wire [3:0] pick_rrobin_1hot, pick_rev_rrobin_1hot, pick_rrobin_1hot_mx ; wire events_pick_dir_d1 ; wire events_pick_dir ; wire [3:0] pick_rrobin_status_or_one_hot ; wire [3:0] pick_rrobin_din ; wire [3:0] pick_rrobin ; wire pick_rrobin_reset ; wire pick_rrobin_dir_upd ; wire [3:0] pick_rrobin_events ; dffrl_async rstff(.din (grst_l), .q (dbb_reset_l), .clk (clk), .se(se), .si(), .so(), .rst_l (arst_l)); assign reset = ~dbb_reset_l; assign clk = rclk; //******************************************************************************************************* //PICK //******************************************************************************************************* //pick for thread force events assign thread_force_events_sel = |(events[3:0] & thread_force[3:0]) ; assign thread_force_pe_mask[3:0] = events[3:0] & thread_force[3:0] ; assign pick_thread_force_1hot[0] = thread_force_pe_mask[0] ; assign pick_thread_force_1hot[1] = thread_force_pe_mask[1] & ~thread_force_pe_mask[0] ; assign pick_thread_force_1hot[2] = thread_force_pe_mask[2] & ~|thread_force_pe_mask[1:0] ; assign pick_thread_force_1hot[3] = thread_force_pe_mask[3] & ~|thread_force_pe_mask[2:0] ; //pick for round robin events assign pick_rrobin_events[3:0] = events[3:0] & ~pick_rrobin[3:0] ; assign pick_rrobin_1hot[0] = ~events_pick_dir_d1 & pick_rrobin_events[0] ; assign pick_rrobin_1hot[1] = ~events_pick_dir_d1 & pick_rrobin_events[1] & ~pick_rrobin_events[0] ; assign pick_rrobin_1hot[2] = ~events_pick_dir_d1 & pick_rrobin_events[2] & ~|pick_rrobin_events[1:0] ; assign pick_rrobin_1hot[3] = ~events_pick_dir_d1 & pick_rrobin_events[3] & ~|pick_rrobin_events[2:0] ; //pick for reverse round robin events assign pick_rev_rrobin_1hot[0] = events_pick_dir_d1 & pick_rrobin_events[0] & ~|pick_rrobin_events[3:1] ; assign pick_rev_rrobin_1hot[1] = events_pick_dir_d1 & pick_rrobin_events[1] & ~|pick_rrobin_events[3:2] ; assign pick_rev_rrobin_1hot[2] = events_pick_dir_d1 & pick_rrobin_events[2] & ~|pick_rrobin_events[3] ; assign pick_rev_rrobin_1hot[3] = events_pick_dir_d1 & pick_rrobin_events[3] ; assign pick_rrobin_1hot_mx[3:0] = pick_rev_rrobin_1hot[3:0] | pick_rrobin_1hot[3:0] ; assign pick_one_hot[3:0] = thread_force_events_sel ? pick_thread_force_1hot[3:0] : pick_rrobin_1hot_mx[3:0] ; //******************************************************************************************************* //******************************************************************************************************* //PICK ROUND ROBIN (bug4814) //******************************************************************************************************* // this is used if there are no requests to be picked based on pick_status[3:0] assign pick_rrobin_status_or_one_hot[3:0] = pick_rrobin[3:0] | events_picked[3:0] ; assign pick_rrobin_reset = reset | ~|(events[3:0] & ~pick_rrobin_status_or_one_hot[3:0]) ; //change direction bit only when events are non-zero assign pick_rrobin_dir_upd = |events[3:0] & (~|(events[3:0] & ~pick_rrobin_status_or_one_hot[3:0])) ; // make reset dominant assign pick_rrobin_din[3:0] = pick_rrobin_status_or_one_hot[3:0] & ~{4{pick_rrobin_reset}}; dff_s #(4) ff_pick_rrobin ( .din (pick_rrobin_din[3:0]), .q (pick_rrobin[3:0] ), .clk (clk), .se (1'b0), .si (), .so () ); //******************************************************************************************************* //******************************************************************************************************* // PICK DIRECTION //******************************************************************************************************* //bug4609 - change direction of pick all events are picked in round robin pick // this is needed when the condition below occurs. assuming misc is less frequent // this should pick load/store in round robin fashion //------------------------------------------------------- // cycle 0 1 2 //------------------------------------------------------- // history{misc,st,ld} 010 011 011 // vld{misc,st,ld} 011 011 011 //------------------------------------------------------- assign events_pick_dir = ~reset & (( ~pick_rrobin_dir_upd & events_pick_dir_d1) | //hold ( pick_rrobin_dir_upd & ~events_pick_dir_d1)) ; //set - invert direction dff_s #(1) ff_events_pick_dir ( .din (events_pick_dir), .q (events_pick_dir_d1), .clk (clk), .se (1'b0), .si (), .so () ); //******************************************************************************************************* endmodule