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[/] [theia_gpu/] [branches/] [icarus_version/] [rtl/] [Module_BusArbitrer.v] - Rev 192
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`timescale 1ns / 1ps `include "aDefinitions.v" /********************************************************************************** Theia, Ray Cast Programable graphic Processing Unit. Copyright (C) 2010 Diego Valverde (diego.valverde.g@gmail.com) This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This 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 program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. ***********************************************************************************/ module Module_BusArbitrer ( input wire Clock, input wire Reset, input wire [`MAX_CORES-1:0] iRequest, output wire [`MAX_CORES-1:0] oGrant, output wire [`MAX_CORE_BITS-1:0] oBusSelect ); wire[`MAX_CORES-1:0] wCurrentMasterMask; wire[`MAX_CORE_BITS-1:0] wCurrentBusMaster; wire wCurrentRequest; //Just one requester can have the bus at a given //point in time, the mask makes sure this happens genvar i; generate for (i = 0; i < `MAX_CORES; i = i +1) begin : ARB assign oGrant[i] = iRequest[i] & wCurrentMasterMask[i]; end endgenerate //When a requester relinquishes the bus (by negating its [iRequest] signal), //the switch is turned to the next position //So while iRequest == 1 the ciruclar list will not move CIRCULAR_SHIFTLEFT_POSEDGE_EX # (`MAX_CORES) SHL_A ( .Clock( Clock ), .Enable( ~wCurrentRequest ), .Reset( Reset ), .Initial(`MAX_CORES'b1), .O( wCurrentMasterMask ) ); assign oBusSelect = wCurrentBusMaster; //Poll the current request assign wCurrentRequest = iRequest[ wCurrentBusMaster ]; UPCOUNTER_POSEDGE # (`MAX_CORE_BITS ) UP1 ( .Clock( Clock ), .Reset( Reset ), .Initial( `MAX_CORE_BITS'd0 ), .Enable(~wCurrentRequest), .Q(wCurrentBusMaster) ); endmodule
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