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Line 145... |
begin --architecture
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begin --architecture
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pause_any <= (mem_pause or pause_ctrl) or (pause_mult or pause_pipeline);
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pause_any <= (mem_pause or pause_ctrl) or (pause_mult or pause_pipeline);
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pause_non_ctrl <= (mem_pause or pause_mult) or pause_pipeline;
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pause_non_ctrl <= (mem_pause or pause_mult) or pause_pipeline;
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pause_bank <= (mem_pause or pause_ctrl or pause_mult) and not pause_pipeline;
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pause_bank <= (mem_pause or pause_ctrl or pause_mult) and not pause_pipeline;
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nullify_op <= '1' when pc_source = from_lbranch and take_branch = '0' else '0';
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nullify_op <= '1' when (pc_source = from_lbranch and take_branch = '0')
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or intr_signal = '1'
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else '0';
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c_bus <= c_alu or c_shift or c_mult;
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c_bus <= c_alu or c_shift or c_mult;
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reset <= '1' when reset_in = '1' or reset_reg /= "1111" else '0';
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reset <= '1' when reset_in = '1' or reset_reg /= "1111" else '0';
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--synchronize reset and interrupt pins
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--synchronize reset and interrupt pins
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intr_proc: process(clk, reset_in, reset_reg, intr_in, intr_enable,
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intr_proc: process(clk, reset_in, reset_reg, intr_in, intr_enable,
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pc_source, pc, pause_any)
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pc_source, pc, pause_any)
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begin
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begin
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if reset_in = '1' then
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if reset_in = '1' then
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reset_reg <= "0000";
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reset_reg <= "0000";
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intr_signal <= '0';
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elsif rising_edge(clk) then
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elsif rising_edge(clk) then
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if reset_reg /= "1111" then
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if reset_reg /= "1111" then
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reset_reg <= reset_reg + 1;
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reset_reg <= reset_reg + 1;
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end if;
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end if;
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--don't try to interrupt a multi-cycle instruction
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--don't try to interrupt a multi-cycle instruction
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if pause_any = '0' then
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if intr_in = '1' and intr_enable = '1' and
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if intr_in = '1' and intr_enable = '1' and
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pc_source = from_inc4 and pc(2) = '0' and
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pc_source = from_inc4 and pc(2) = '0' then
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pause_any = '0' then
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--the epc will be backed up one opcode (pc-4)
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--the epc will be backed up one opcode (pc-4)
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intr_signal <= '1';
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intr_signal <= '1';
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else
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else
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intr_signal <= '0';
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intr_signal <= '0';
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end if;
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end if;
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end if;
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end if;
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end if;
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end process;
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end process;
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u1_pc_next: pc_next PORT MAP (
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u1_pc_next: pc_next PORT MAP (
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clk => clk,
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clk => clk,
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reset_in => reset,
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reset_in => reset,
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