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Line 1... |
-------------------------------------------------------------------------------
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-------------------------------------------------------------------------------
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--
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--
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-- The Decoder unit.
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-- The Decoder unit.
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-- It decodes the instruction opcodes and executes them.
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-- It decodes the instruction opcodes and executes them.
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--
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--
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-- $Id: decoder.vhd,v 1.12 2004-05-17 14:40:09 arniml Exp $
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-- $Id: decoder.vhd,v 1.13 2004-05-20 21:51:40 arniml Exp $
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--
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--
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-- Copyright (c) 2004, Arnim Laeuger (arniml@opencores.org)
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-- Copyright (c) 2004, Arnim Laeuger (arniml@opencores.org)
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--
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--
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-- All rights reserved
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-- All rights reserved
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--
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--
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| Line 345... |
Line 345... |
pm_inc_pc_s <= true;
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pm_inc_pc_s <= true;
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end if;
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end if;
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when MSTATE3 =>
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when MSTATE3 =>
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if need_address_v then
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if need_address_v then
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-- Theory of operation:
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-- Program Memory address is updated at end of State 3 (or end of
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-- State 2 in case of a RET). Address information is thus available
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-- latest with State 4.
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-- This is the time where we need information about access target
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-- (internal or external = EA). EA information needs to be stable
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-- until end of State 1.
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pm_write_pmem_addr_s <= true;
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pm_write_pmem_addr_s <= true;
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end if;
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end if;
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if ea_i = '1' and
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(need_address_v and last_cycle_s) then
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bus_output_pcl_o <= true;
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end if;
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when MSTATE4 =>
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when MSTATE4 =>
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if ea_i = '1' and
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if ea_i = '1' and
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(need_address_v or last_cycle_s) then
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(need_address_v or last_cycle_s) then
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clk_assert_psen_o <= true;
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clk_assert_psen_o <= true;
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p2_output_pch_o <= true;
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p2_output_pch_o <= true;
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bus_output_pcl_o <= true;
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bus_output_pcl_o <= true;
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end if;
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end if;
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when MSTATE5 =>
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when MSTATE5 =>
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if ea_i = '1' and
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if ea_i = '1' and
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(need_address_v and last_cycle_s) then
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(need_address_v or last_cycle_s) then
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clk_assert_psen_o <= true;
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p2_output_pch_o <= true;
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p2_output_pch_o <= true;
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end if;
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end if;
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when others =>
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when others =>
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-- pragma translate_off
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-- pragma translate_off
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| Line 1930... |
Line 1931... |
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-------------------------------------------------------------------------------
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-------------------------------------------------------------------------------
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-- File History:
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-- File History:
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--
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--
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-- $Log: not supported by cvs2svn $
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-- $Log: not supported by cvs2svn $
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-- Revision 1.12 2004/05/17 14:40:09 arniml
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-- assert p2_read_p2_o when expander port is read
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--
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-- Revision 1.11 2004/05/16 15:33:39 arniml
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-- Revision 1.11 2004/05/16 15:33:39 arniml
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-- work around bug in Quartus II 4.0
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-- work around bug in Quartus II 4.0
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--
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--
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-- Revision 1.10 2004/04/25 16:22:03 arniml
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-- Revision 1.10 2004/04/25 16:22:03 arniml
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-- adjust external timing of BUS
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-- adjust external timing of BUS
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