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[/] [rtf65002/] [trunk/] [rtl/] [verilog/] [byte_irq.v] - Blame information for rev 21

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// ============================================================================
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//        __
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//   \\__/ o\    (C) 2013  Robert Finch, Stratford
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//    \  __ /    All rights reserved.
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//     \/_//     robfinch<remove>@opencores.org
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//       ||
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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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// IRQ processing states for 65C02 emulation mode
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// The high order PC[31:16] is set to zero, forcing the IRQ routine to be in bank zero.
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//
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BYTE_IRQ1:
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        if (ack_i) begin
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                ir <= 64'd0;
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                state <= BYTE_IRQ2;
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                retstate <= BYTE_IRQ2;
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                cyc_o <= 1'b0;
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                stb_o <= 1'b0;
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                we_o <= 1'b0;
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                sel_o <= 4'h0;
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                sp <= sp_dec;
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                if (dhit) begin
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                        wrsel <= sel_o;
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                        wr <= 1'b1;
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                end
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                else if (write_allocate) begin
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                        state <= WAIT_DHIT;
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                        dmiss <= `TRUE;
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                end
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        end
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BYTE_IRQ2:
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        begin
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                radr <= {spage[31:8],sp[7:2]};
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                radr2LSB <= sp[1:0];
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                wadr <= {spage[31:8],sp[7:2]};
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                wadr2LSB <= sp[1:0];
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                wdat <= {4{pc[23:16]}};
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                cyc_o <= 1'b1;
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                stb_o <= 1'b1;
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                we_o <= 1'b1;
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                case(sp[1:0])
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                2'd0:   sel_o <= 4'b0001;
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                2'd1:   sel_o <= 4'b0010;
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                2'd2:   sel_o <= 4'b0100;
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                2'd3:   sel_o <= 4'b1000;
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                endcase
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                adr_o <= {spage[31:8],sp[7:2],2'b00};
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                dat_o <= {4{pc[23:16]}};
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                state <= BYTE_IRQ3;
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        end
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BYTE_IRQ3:
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        if (ack_i) begin
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                state <= BYTE_IRQ4;
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                retstate <= BYTE_IRQ4;
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                cyc_o <= 1'b0;
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                stb_o <= 1'b0;
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                we_o <= 1'b0;
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                sel_o <= 4'h0;
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                sp <= sp_dec;
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                if (dhit) begin
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                        wrsel <= sel_o;
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                        wr <= 1'b1;
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                end
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                else if (write_allocate) begin
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                        state <= WAIT_DHIT;
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                        dmiss <= `TRUE;
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                end
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        end
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BYTE_IRQ4:
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        begin
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                radr <= {spage[31:8],sp[7:2]};
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                radr2LSB <= sp[1:0];
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                wadr <= {spage[31:8],sp[7:2]};
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                wadr2LSB <= sp[1:0];
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                wdat <= {4{pc[15:8]}};
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                cyc_o <= 1'b1;
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                stb_o <= 1'b1;
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                we_o <= 1'b1;
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                case(sp[1:0])
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                2'd0:   sel_o <= 4'b0001;
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                2'd1:   sel_o <= 4'b0010;
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                2'd2:   sel_o <= 4'b0100;
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                2'd3:   sel_o <= 4'b1000;
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                endcase
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                adr_o <= {spage[31:8],sp[7:2],2'b00};
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                dat_o <= {4{pc[15:8]}};
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                state <= BYTE_IRQ5;
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        end
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BYTE_IRQ5:
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        if (ack_i) begin
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                state <= BYTE_IRQ6;
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                retstate <= BYTE_IRQ6;
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                cyc_o <= 1'b0;
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                stb_o <= 1'b0;
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                we_o <= 1'b0;
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                sel_o <= 4'h0;
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                sp <= sp_dec;
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                if (dhit) begin
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                        wrsel <= sel_o;
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                        wr <= 1'b1;
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                end
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                else if (write_allocate) begin
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                        state <= WAIT_DHIT;
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                        dmiss <= `TRUE;
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                end
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        end
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BYTE_IRQ6:
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        begin
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                radr <= {spage[31:8],sp[7:2]};
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                radr2LSB <= sp[1:0];
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                wadr <= {spage[31:8],sp[7:2]};
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                wadr2LSB <= sp[1:0];
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                wdat <= {4{pc[7:0]}};
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                cyc_o <= 1'b1;
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                stb_o <= 1'b1;
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                we_o <= 1'b1;
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                case(sp[1:0])
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                2'd0:   sel_o <= 4'b0001;
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                2'd1:   sel_o <= 4'b0010;
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                2'd2:   sel_o <= 4'b0100;
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                2'd3:   sel_o <= 4'b1000;
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                endcase
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                adr_o <= {spage[31:8],sp[7:2],2'b00};
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                dat_o <= {4{pc[7:0]}};
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                state <= BYTE_IRQ7;
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        end
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BYTE_IRQ7:
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        if (ack_i) begin
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                state <= BYTE_IRQ8;
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                retstate <= BYTE_IRQ8;
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                cyc_o <= 1'b0;
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                stb_o <= 1'b0;
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                we_o <= 1'b0;
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                sel_o <= 4'h0;
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                sp <= sp_dec;
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                if (dhit) begin
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                        wrsel <= sel_o;
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                        wr <= 1'b1;
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                end
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                else if (write_allocate) begin
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                        state <= WAIT_DHIT;
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                        dmiss <= `TRUE;
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                end
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        end
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BYTE_IRQ8:
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        begin
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                radr <= {spage[31:8],sp[7:2]};
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                radr2LSB <= sp[1:0];
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                wadr <= {spage[31:8],sp[7:2]};
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                wadr2LSB <= sp[1:0];
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                wdat <= {4{sr8[7:0]}};
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                cyc_o <= 1'b1;
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                stb_o <= 1'b1;
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                we_o <= 1'b1;
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                case(sp[1:0])
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                2'd0:   sel_o <= 4'b0001;
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                2'd1:   sel_o <= 4'b0010;
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                2'd2:   sel_o <= 4'b0100;
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                2'd3:   sel_o <= 4'b1000;
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                endcase
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                adr_o <= {spage[31:8],sp[7:2],2'b00};
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                dat_o <= {4{sr8[7:0]}};
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                state <= BYTE_IRQ9;
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        end
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BYTE_IRQ9:
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        if (ack_i) begin
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                state <= BYTE_JMP_IND1;
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                retstate <= BYTE_JMP_IND1;
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                cyc_o <= 1'b0;
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                stb_o <= 1'b0;
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                we_o <= 1'b0;
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                sel_o <= 4'h0;
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                sp <= sp_dec;
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                if (dhit) begin
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                        wrsel <= sel_o;
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                        wr <= 1'b1;
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                end
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                else if (write_allocate) begin
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                        state <= WAIT_DHIT;
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                        dmiss <= `TRUE;
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                end
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                pc[31:16] <= 16'h0000;
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                radr <= vect[31:2];
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                radr2LSB <= vect[1:0];
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        end
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