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[/] [klc32/] [trunk/] [rtl/] [verilog/] [RTI.v] - Blame information for rev 6

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Line No. Rev Author Line
1 2 robfinch
// ============================================================================
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// (C) 2011 Robert Finch
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// All Rights Reserved.
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// robfinch<remove>@opencores.org
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//
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// KLC32 - 32 bit CPU
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// RTI.v - return from interrupt / trap
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//
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// This source file is free software: you can redistribute it and/or modify 
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// it under the terms of the GNU Lesser General Public License as published 
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// by the Free Software Foundation, either version 3 of the License, or     
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// (at your option) any later version.                                      
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//                                                                          
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// This source file is distributed in the hope that it will be useful,      
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// but WITHOUT ANY WARRANTY; without even the implied warranty of           
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            
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// GNU General Public License for more details.                             
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//                                                                          
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// You should have received a copy of the GNU General Public License        
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// along with this program.  If not, see <http://www.gnu.org/licenses/>.    
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//                                                                          
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// ============================================================================
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//
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RTI1:
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        if (!cyc_o) begin
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                fc_o <= {3'b101};
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                cyc_o <= 1'b1;
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                stb_o <= 1'b1;
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                sel_o <= 4'b1111;
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                adr_o <= ssp;
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        end
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        else if (ack_i) begin
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                stb_o <= 1'b0;
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                sel_o <= 4'b0000;
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                im <= dat_i[18:16];
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                sf <= dat_i[21];
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                tf <= dat_i[23];
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                ssp <= ssp + 32'd4;
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                state <= RTI2;
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        end
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RTI2:
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        if (!stb_o) begin
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                fc_o <= {3'b101};
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                stb_o <= 1'b1;
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                sel_o <= 4'b1111;
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                adr_o <= ssp;
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        end
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        else if (ack_i) begin
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                stb_o <= 1'b0;
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                sel_o <= 4'b0000;
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                cr0 <= dat_i[3:0];
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                cr1 <= dat_i[7:4];
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                cr2 <= dat_i[11:8];
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                cr3 <= dat_i[15:12];
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                cr4 <= dat_i[19:16];
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                cr5 <= dat_i[23:20];
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                cr6 <= dat_i[27:24];
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                cr7 <= dat_i[31:28];
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                ssp <= ssp + 32'd4;
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                state <= RTI3;
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        end
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RTI3:
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        if (!stb_o) begin
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                fc_o <= {3'b101};
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                stb_o <= 1'b1;
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                sel_o <= 4'b1111;
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                adr_o <= ssp;
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        end
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        else if (ack_i) begin
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                cyc_o <= 1'b0;
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                stb_o <= 1'b0;
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                sel_o <= 4'b0000;
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                pc <= dat_i;
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                ssp <= ssp + 32'd4;
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                state <= IFETCH;
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        end

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